U.S. patent application number 14/512729 was filed with the patent office on 2015-06-11 for wayside monitoring system and method.
The applicant listed for this patent is General Electric Company. Invention is credited to Jeffrey Michael Fries, Richard Lee Lawson, Curtis Doyle Mechling, Aaron Richard Mitti, Joseph Forrest Noffsinger, Martin Paget, William David Shields, Aric Albert Weingartner.
Application Number | 20150158510 14/512729 |
Document ID | / |
Family ID | 53270358 |
Filed Date | 2015-06-11 |
United States Patent
Application |
20150158510 |
Kind Code |
A1 |
Fries; Jeffrey Michael ; et
al. |
June 11, 2015 |
WAYSIDE MONITORING SYSTEM AND METHOD
Abstract
A wayside monitoring method and system monitor a transmitted
current that is injected into conductive components of a route
traveled by vehicle systems, monitor a received current that
represents a portion of the transmitted current that is conducted
through the conductive components of the route, examine changes in
the transmitted and/or received current over time to determine when
the vehicle systems are on the route between a first location where
the transmitted current is injected into the conductive components
and a second location where the received current is monitored, and
examine the changes in the transmitted and/or received currents.
The changes are examined to identify (a) a contaminated portion of
a surface on which the route is disposed, (b) a foreign object
other than the vehicle systems that is contacting the route, and/or
(c) a damaged or broken portion of at least one of the conductive
components of the route.
Inventors: |
Fries; Jeffrey Michael;
(Grain Valley, MO) ; Noffsinger; Joseph Forrest;
(Grain Valley, MO) ; Lawson; Richard Lee;
(Melbourne, FL) ; Weingartner; Aric Albert; (Lee's
Summit, MO) ; Mechling; Curtis Doyle; (Jacksonville,
FL) ; Mitti; Aaron Richard; (Atlanta, GA) ;
Paget; Martin; (Saint Johns, FL) ; Shields; William
David; (Grain Valley, MO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
53270358 |
Appl. No.: |
14/512729 |
Filed: |
October 13, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61912069 |
Dec 5, 2013 |
|
|
|
Current U.S.
Class: |
701/19 |
Current CPC
Class: |
B61L 1/20 20130101; B61L
23/044 20130101; B61L 15/0036 20130101; G01N 27/041 20130101; B61L
23/041 20130101; B61L 23/047 20130101; B61L 3/10 20130101; G01N
27/20 20130101; B61L 1/181 20130101; G01V 3/02 20130101; B61L
15/0081 20130101 |
International
Class: |
B61L 1/18 20060101
B61L001/18; B61L 1/20 20060101 B61L001/20 |
Claims
1. A method comprising: monitoring a transmitted current that is
injected into conductive components of a route that is traveled by
one or more vehicle systems; monitoring a received current that
represents at least a portion of the transmitted current that is
conducted through the conductive components of the route; examining
changes in one or more of the transmitted current or the received
current over time to determine when at least one of the vehicle
systems is disposed on the route between a first location along the
route where the transmitted current is injected into the conductive
components and a different, second location along the route where
the received current is monitored; and examining the same changes
in the one or more of the transmitted current or the received
current to identify one or more of a contaminated portion of a
surface on which the conductive components of the route are
disposed, to identify a foreign object other than the one or more
vehicle systems that is contacting the conductive components of the
route, or to identify a damaged or broken portion of at least one
of the conductive components of the route.
2. The method of claim 1, wherein the changes that are examined to
both determine when at least one of the vehicle systems is disposed
on the route and to identify the at least one of the contaminated
portion, the foreign object, or the damaged or broken portion of
the at least one of the conductive components of the route include
increases or decreases in the transmitted current and the received
current and time periods over which the increases or decreases in
the transmitted current and the received current occur.
3. The method of claim 1, wherein the contaminated portion of the
surface includes a portion of ballast material disposed beneath the
conductive components of the route that at least partially conducts
the transmitted current between the conductive components of the
route through the contaminated portion of the surface.
4. The method of claim 1, wherein the foreign object that is
identified is one or more conductive bodies forming a short between
the conductive components of the route.
5. The method of claim 1, wherein the damaged or broken portion of
the at least one of the conductive components of the route includes
a portion of the at least one of the conductive components that is
separated through an entire cross-sectional area of the at least
one of the conductive components.
6. The method of claim 1, wherein the contaminated portion of the
surface on which the conductive components of the route are
disposed is identified when the changes in the transmitted current
and in the received current include an increasing trend in the
transmitted current over an extended period of time that
concurrently occurs with a decreasing trend in the received current
over the extended period of time.
7. The method of claim 1, wherein the foreign object is identified
when the changes in the received current include a decrease in the
received current to zero current or approximately zero current and
temporary changes in the received current that are temporally
correlated with temporary changes in the transmitted current.
8. The method of claim 1, wherein the damaged or broken portion of
the at least one of the conductive components of the route is
identified when the changes in the transmitted current and in the
received current include a decrease in the transmitted current that
occurs concurrently with an elimination of the received
current.
9. A wayside monitoring system comprising: a transmit monitor
including one or more processors configured to measure a
transmitted current that is injected into conductive components of
a route that is traveled by one or more vehicle systems; and a
receive monitor including one or more processors configured to
measure a received current that represents at least a portion of
the transmitted current that is conducted through the conductive
components of the route; wherein at least one of the transmit
monitor or the receive monitor is configured to examine changes in
one or more of the transmitted current or the received current over
time to determine when at least one of the vehicle systems is
disposed on the route between a first location along the route
where the transmitted current is injected into the conductive
components and a different, second location along the route where
the received current is monitored, and wherein at least one of the
transmit monitor or the receive monitor is configured to examine
the same changes in the one or more of the transmitted current or
the received current to identify at least one of a contaminated
portion of a surface on which the conductive components of the
route are disposed, to identify a foreign object other than the one
or more vehicle systems that is contacting the conductive
components of the route, or to identify a damaged or broken portion
of at least one of the conductive components of the route.
10. The system of claim 9, wherein the at least one of the transmit
monitor or the receive monitor is configured to examine the changes
in the transmitted current and in the received current to both
determine when at least one of the vehicle systems is disposed on
the route and to identify the at least one of the contaminated
portion, the foreign object, or the damaged or broken portion by
identifying: increases or decreases in the transmitted current and
the received current, and time periods over which the increases or
decreases in the transmitted current and the received current
occur.
11. The system of claim 9, wherein the at least one of the transmit
monitor or the receive monitor is configured to identify the
contaminated portion of the surface as a portion of ballast
material disposed beneath the conductive components of the route
that at least partially conducts the transmitted current between
the conductive components of the route through the contaminated
portion of the surface.
12. The system of claim 9, wherein the at least one of the transmit
monitor or the receive monitor is configured to identify the
foreign object as one or more conductive bodies forming a short
between the conductive components of the route.
13. The system of claim 9, wherein the at least one of the transmit
monitor or the receive monitor is configured to identify the
damaged or broken portion of the at least one of the conductive
components of the route as a portion of the at least one of the
conductive components that is separated through an entire
cross-sectional area of the at least one of the conductive
components.
14. The system of claim 9, wherein the at least one of the transmit
monitor or the receive monitor is configured to identify the
contaminated portion of the surface responsive to the changes in
the transmitted current and in the received current including an
increasing trend in the transmitted current over an extended period
of time that concurrently occurs with a decreasing trend in the
received current over the extended period of time.
15. The system of claim 9, wherein the at least one of the transmit
monitor or the receive monitor is configured to identify the
foreign object responsive to the changes in the received current
including a decrease in the received current to zero current or
approximately zero current and temporary changes in the received
current being temporally correlated with temporary changes in the
transmitted current.
16. The system of claim 9, wherein the at least one of the transmit
monitor or the receive monitor is configured to identify the
damaged or broken portion of the at least one of the conductive
components of the route is identified responsive to the changes in
the transmitted current and in the received current including a
decrease in the transmitted current that occurs concurrently with
an elimination of the received current.
17. A method comprising: measuring a transmitted current that is
applied to a conductive rail of a track over which one or more rail
vehicles travel at a first location; measuring a received current
at a different, second location to the conductive rails of the
track, the received current including at least a portion of the
transmitted current that is conducted through one or more of the
conductive rails from the first location to the second location;
and identifying changes in the transmitted current and in the
received current over time in order to both identify when the one
or more of the rail vehicles travel between the first location and
the second location and when at least one of: ballast material
disposed between the conductive rails becomes contaminated to at
least partially form a short between the conductive rails, a
foreign object other than the one or more rail vehicles forms the
short between the conductive rails, or one or more of the
conductive rails is damaged or broken between the first location
and the second location.
18. The method of claim 17, wherein the changes in the transmitted
current and the changes in the received current indicate that the
ballast material is contaminated when the transmitted current
increases and the received current decreases over an extended
period of time that is longer than a time period during which the
one or more rail vehicles travel over the conductive rails between
the first location and the second location at a track speed of the
conductive rails.
19. The method of claim 17, wherein the changes in the transmitted
current and the changes in the received current indicate that the
foreign object is forming the short between the conductive rails
responsive to the transmitted current increasing and the received
current concurrently decreasing, followed by one or more temporary
changes in the transmitted current and one or more temporary
changes in the received current occurring during common time
periods.
20. The method of claim 17, wherein the changes in the transmitted
current and the changes in the received current indicate that one
or more of the conductive rails is damaged or broken when the
transmitted current decreases and the received current is
concurrently eliminated.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 61/912,069, which was filed on 5 Dec. 2013, and the
entire disclosure of which is incorporated herein by reference.
FIELD
[0002] Embodiments of the inventive subject matter described herein
relate to electrically monitoring a route traveled by one or more
vehicle systems.
BACKGROUND
[0003] Some wayside monitoring systems monitor electric current
that is conducted in rails of a track to determine when rail
vehicles travel on certain segments of the track. When a rail
vehicle travels on the segment of the track through which current
is being conducted, the rail vehicle can short out a circuit that
includes the rails of the track. This shorting of the circuit can
be detected so that the presence of the rail vehicle on the track
can be automatically detected.
[0004] These systems rely on assumptions that no external factors
otherwise impact the conduction of current through the rails of the
track. For example, if another foreign object or body creates or
forms a short or shunt in the circuit that includes the rails of
the track, the wayside monitoring system that is monitoring that
segment of the track may incorrectly determine that a rail vehicle
is on the segment of the track. This incorrect determination can
result in disruption of the flow of traffic in a transportation
network that includes the track.
[0005] For example, after incorrectly identifying a segment of the
track as being occupied by a rail vehicle, the wayside monitoring
system may automatically change a traffic or warning signal to
erroneously indicate to other rail vehicles that the segment of the
track is occupied. Additionally or alternatively, the wayside
monitoring system may incorrectly notify a dispatch center that the
segment of the track is occupied, which can prevent the dispatch
center from using that segment of the track to route rail
vehicles.
[0006] The erroneous identification of a rail vehicle on the
segment of track may only be identified by an operator after an
extended period of time. Then, one or more persons may be required
to travel to the route segment and visually inspect the segment of
track to identify the cause of the errors by the wayside monitoring
system. The wayside monitoring system may be unable to identify any
potential cause for the errors to the persons seeking to repair the
problem with the track.
BRIEF DESCRIPTION
[0007] In one embodiment, a wayside monitoring method includes
monitoring a transmitted current that is injected into conductive
components of a route that is traveled by one or more vehicle
systems, monitoring a received current that represents at least a
portion of the transmitted current that is conducted through the
conductive components of the route, examining changes in one or
more of the transmitted current or the received current over time
to determine when at least one of the vehicle systems is disposed
on the route between a first location along the route where the
transmitted current is injected into the conductive components and
a different, second location along the route where the received
current is monitored, and examining the same changes in the one or
more of the transmitted current or the received current to identify
at least one of a contaminated portion of a surface on which the
conductive components of the route are disposed, to identify a
foreign object other than the one or more vehicle systems that is
contacting the conductive components of the route, or to identify a
damaged or broken portion of at least one of the conductive
components of the route.
[0008] In another embodiment, a wayside monitoring system includes
a transmit monitor and a receive monitor. The transmit monitor
includes one or more processors configured to measure a transmitted
current that is injected into conductive components of a route that
is traveled by one or more vehicle systems. The receive monitor
includes one or more processors (which may be one or more of the
same processors as the transmit monitor or different processors
than the transmit monitor) that are configured to measure a
received current that represents at least a portion of the
transmitted current that is conducted through the conductive
components of the route. At least one of the transmit monitor or
the receive monitor also is configured to examine changes in one or
more of the transmitted current or the received current over time
to determine when at least one of the vehicle systems is disposed
on the route between a first location along the route where the
transmitted current is injected into the conductive components and
a different, second location along the route where the received
current is monitored. At least one of the transmit monitor or the
receive monitor is configured to examine the same changes in the
one or more of the transmitted current or the received current to
identify at least one of a contaminated portion of a surface on
which the conductive components of the route are disposed, to
identify a foreign object other than the one or more vehicle
systems that is contacting the conductive components of the route,
or to identify a damaged or broken portion of at least one of the
conductive components of the route.
[0009] In another embodiment, a wayside monitoring method includes
measuring a transmitted current that is applied at a first location
to conductive rails of a track over which one or more rail vehicles
travel and measuring a received current at a different, second
location to the conductive rails of the track. The received current
includes at least a portion of the transmitted current that is
conducted through one or more of the conductive rails from the
first location to the second location. The method also can include
identifying changes in the transmitted current and in the received
current over time in order to both identify when the one or more of
the rail vehicles travel between the first location and the second
location and when at least one of: ballast material disposed
between the conductive rails becomes contaminated to at least
partially form a short between the conductive rails, a foreign
object other than the one or more rail vehicles forms the short
between the conductive rails, or one or more of the conductive
rails is damaged or broken between the first location and the
second location.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Reference is now made briefly to the accompanying drawings,
in which:
[0011] FIG. 1 is a schematic diagram of a wayside monitoring system
in accordance with one aspect of the inventive subject matter
described herein;
[0012] FIG. 2 illustrates another schematic diagram of the wayside
monitoring system shown in FIG. 1;
[0013] FIG. 3 illustrates changes in a transmitted current that is
injected into conductive components of a route shown in FIG. 1 and
changes in a received current that is conducted by the conductive
components of the route when a vehicle system travels along the
route;
[0014] FIG. 4 illustrates examples of changes in the transmitted
current and changes in the received current when ballast material
on which the route is positioned becomes contaminated;
[0015] FIG. 5 illustrates examples of changes in the transmitted
current and in the received current when a foreign object extends
across the conductive components of the route;
[0016] FIG. 6 illustrates examples of changes in the transmitted
current and in the received current when one or more of the
conductive components of the route are damaged or broken;
[0017] FIG. 7 is another schematic illustration of the monitoring
system shown in FIG. 1;
[0018] FIG. 8 illustrates transmitted and received currents that
are measured by several monitoring systems connected with different
segments of the same route in accordance with one embodiment;
and
[0019] FIGS. 9A and 9B illustrate a flowchart of a method for
monitoring a segment of a route in accordance with one embodiment
of the inventive subject matter.
DETAILED DESCRIPTION
[0020] One or more embodiments of the inventive subject matter
described herein provide wayside monitoring systems and methods
that monitor electrical characteristics of a segment of a route on
which one or more vehicles may travel. The electrical
characteristics are monitored in order to detect the presence of a
vehicle system (e.g., a single vehicle, or two or more vehicles
mechanically coupled together to travel together along the route,
such as in a consist) on the route segment. For example, the route
may include plural conductive components (e.g., rails) and the
vehicle system may include wheels connected by axles that, when the
wheels contact the conductive components of the route, form a
conductive pathway or bridge between the conductive components of
the route. The systems and methods described herein can monitor
changes in electrical characteristics of the conductive components
of the route (e.g., changes in an electric current transmitted and
received along the conductive components of the route) in order to
detect the presence (or absence) of the vehicle system on the
route.
[0021] Additionally, the systems and methods can examine the
electric characteristics over time to identify trends or other
changes in the characteristics that may be emblematic of one or
more problems with the route. For example, significant increases in
an electric current that is injected into the conductive components
of the route (which also can be referred to as a transmitted
current) and/or significant decreases in an electric current that
is received from the conductive components of the route (which also
can be referred to as a received current) over an extended period
of time can signify that the surface or materials on which the
conductive components of the route are positioned (e.g., ballast
material) has become contaminated or otherwise damaged (and may
need cleaning or replacing). Additionally or alternatively, the
systems and methods can determine that the conductive components of
the route have been shorted out (e.g., coupled by a conductive
pathway other than a vehicle system) based on rapid and significant
changes in the transmitted current, the received current, or both
the transmitted current and the received current. Optionally, the
systems and methods can determine that one or more of the
conductive components of the route are damaged (e.g., broken) based
on rapid and significant changes in the transmitted current, the
received current, or both the transmitted current and the received
current.
[0022] Once the systems and methods have identified the problems
with the surface on which the conductive components of the route
are positioned and/or with the conductive components themselves,
the systems and methods can take one or more remedial actions. For
example, signals can be communicated to one or more locations to
request servicing or repair of the surface and/or conductive
components of the route, to request modification of an electronic
circuit that includes the conductive components of the route, to
automatically warn approaching vehicle systems of problems with the
surface and/or conductive components of the route, and the
like.
[0023] One embodiment provides a system and method that measure
track circuit parameters at transmit and receive ends of a track
circuit that includes conductive rails of a track. The system and
method analyze short term and long term trends of the parameters
(e.g., current, resistance, voltage, or the like) in order to
predict imminent failures of the track circuit so that maintenance
is forced or automatically requested to intervene prior to the
failure and, when there is a failure, the system and method can
identify a type of failure to optimize (e.g., reduce) the cost and
timeliness of the response of maintenance to repair the
failure.
[0024] The system and method can monitor and sample electrical
current on the track circuit at each end of the circuit. The
sampled values are periodically transmitted to an analysis
subsystem (e.g., a transmit monitor, a receive monitor, or both),
either wayside on the railway or communicated to a central office.
The analysis subsystem identifies trends in the parameters and
yields decisions on whether the circuit is performing within bounds
or needs maintenance. In an example embodiment, receive current
parameters may trend downward during rain, as the track ballast
becomes wet and more electrically conductive. Over time, typically
in months or years, as ballast stone becomes contaminated with
dirt, the dip in receive current when wet becomes more pronounced.
When the sampled current meets an alarm threshold (e.g., determined
by a learning algorithm or calculated), the risk of a false
occupancy of the track circuit increases. The alarm threshold can
be set to allow a maintainer to intervene and adjust the circuit
before the failure occurs. For example, instead of setting a
threshold at a value at which the circuit would incorrectly
identify a segment of the track as being occupied, the threshold
may be moved downward or upward (as appropriate) so that the
contaminated ballast may be identified before the track circuit
begins incorrectly determining that the track circuit is occupied
by a vehicle system. Over more time, this margin for adjustment
will be depleted, and the system or method will determine that the
ballast stone needs to be cleaned or refreshed.
[0025] In another example, an actual track circuit failure can
occur, and the system and method can identify the type of failure,
such as a short circuit on the track (e.g., due to scrap metal,
failed switch rod insulation, or the like) or a load on the track
due to fouled and or wet ballast conditions outside of a current
adjustment range (e.g., additional resistive elements cannot be
added to the track circuit to reduce the trends in the current, as
described below). Depending on the type of failure, the appropriate
number of maintainers can be automatically requested or dispatched
more efficiently correct the problem.
[0026] The erroneous identification of track occupancies can cause
railway signals to go red (e.g., stop), which disrupts traffic
flow, as well as cause unplanned maintenance expenses. One or more
embodiments of the systems and methods described herein predict
necessary maintenance for low ballast condition failures, allowing
adjustment of the track circuit before failures. If the cause of a
failure is determined to be a short circuit, multiple maintainers
can be dispatched to walk the track circuit to clear the cause of
the failure (e.g., remove scrap metal from a train from the track).
If the system or method determines a failure to be due to fouled
ballast, only one maintainer may need to be dispatched to make
adjustments to the track circuit.
[0027] FIG. 1 is a schematic diagram of a wayside monitoring system
100 in accordance with one aspect of the inventive subject matter
described herein. The monitoring system includes or represents one
or more hardware circuits or circuitry that includes and/or is
coupled with one or more processors, controllers, or other
electronic logic-based devices that operate to perform various
operations described herein. The monitoring system is coupled with
a route 102 on which vehicle systems 104 travel along. The route
102 is positioned on a surface 110 formed from one or more
materials 112. These materials can be referred to as ballast
material, and can include (by way of example only), rock, dirt, or
other types of materials. Optionally, the surface and materials may
represent another surface that does not include ballast material.
Although only a single vehicle system is shown, multiple vehicle
systems may concurrently travel along the route. Additionally, the
vehicle system 104 is shown as including a single vehicle, but
optionally may include multiple vehicles mechanically coupled with
each other to travel together along the route, such as in a
consist. For example, one or more embodiments of the monitoring
system and method described herein may be used in conjunction with
a rail vehicle (e.g., rail vehicle consist, train, or the like)
that travels along a track (e.g., the route). Optionally, the
monitoring system and/or method may be used in conjunction with one
or more other types of vehicles and/or routes.
[0028] The monitoring system 100 is coupled with the route 102 at
two or more spaced apart locations 106, 108. In the illustrated
example, one location may be referred to as a transmitting location
while the other location may be referred to as a receiving
location. The monitoring system may be coupled with the route so
that the monitoring system can inject electric signals (e.g.,
electric currents that are controlled by the monitoring system)
into the route at the transmitting location. The monitoring system
also may be coupled with the route so that the monitoring system
can receive electric signals (e.g., the electric current that is
injected into the route at the transmitting location and that is
conducted along the route) at the receiving location. For example,
the monitoring system may be conductively and/or inductively
coupled with the route at the transmitting and receiving
locations.
[0029] The monitoring system 100 injects the electric signals into
the route 102 at the transmitting location 106 or 108 by applying
an electric current that is controlled by the monitoring system
(e.g., the phase, amplitude, frequency, and the like, is controlled
by the monitoring system) to route, such as to the rails of a
track. This current can be referred to as a transmitting or
transmitted current. The monitoring system can measure the electric
current that is conducted along the route at the receiving location
108 or 106. This current can be referred to as a receiving,
received, sensed, or measured current. Based on changes in the
transmitted current, changes in the received current, and/or
differences between the transmitted and received currents, the
monitoring system can determine if the vehicle system 104 is
traveling along the route between the transmitting and receiving
locations along the route. Additionally, the monitoring system can
track changes in the transmitted current and/or changes in the
received current over time in order to identify and/or predict
damage to the route, as described below.
[0030] FIG. 2 illustrates another schematic diagram of the wayside
monitoring system 100 shown in FIG. 1. In the illustration shown in
FIG. 2, the route 102 is shown from a top view so plural conductive
components 200, 202 (e.g., rails) of the route 102 are visible.
Additionally, the vehicle system 104 is shown in phantom view so
that wheels 204 and axles 206 of the vehicle system are visible.
The wayside monitoring system can be coupled with the conductive
components in the transmitting and receiving locations 106, 108.
The wayside monitoring system can be coupled with or include a
source of electric energy (e.g., a power source) that applies
current to the conductive components at the transmitting location
106. For example, the power source and/or monitoring system can be
conductively coupled with the conductive component 200 of the route
at a positive terminal 208 and with the conductive component 202 of
the route at a negative terminal 210. The transmitted current can
be applied to the conductive components across the positive and
negative terminal. The monitoring system similarly can be
conductively coupled with the conductive components in the
receiving location 108 at corresponding first and second terminals
212, 214.
[0031] With continued reference to the wayside monitoring system
100 shown in FIGS. 1 and 2, FIG. 3 illustrates changes in a
transmitted current 300 that is injected into the conductive
components of the route at the transmitting location 106 along the
route 102 and changes in a received current 302 that is sensed by
the monitoring system at the receiving location 108 along the route
when the vehicle system 104 travels across the route. The
transmitted and received currents are shown alongside a horizontal
axis 304 representative of time (e.g., in terms of minutes or
hours) and a vertical axis 306 representative of a magnitude of the
transmitted and received currents. For example, the vertical axis
can represent different amps of the transmitted and received
currents, voltages of the transmitted and received currents (e.g.,
where the currents are direct currents), or other measurements of
the transmitted and received currents.
[0032] Prior to entry of the vehicle system 104 onto a segment 216
of the route 102 that is between the transmitting and receiving
locations 106, 108 (referred to herein as a route segment under
examination or a monitored route segment), the monitoring system
100 may apply the transmitting current 300 to the conductive
components 200, 202 of the route in the transmitting location at a
first magnitude 308. Due to resistance of the conductive components
between the transmitting location and the receiving location, the
received current 302 may be sensed by the monitoring location at a
smaller, second magnitude 310.
[0033] When the vehicle system 104 enters into the examined segment
216 of the route 102 at a time of entry 316, the vehicle system may
change one or more of the transmitted and/or received currents 300,
302. For example, the wheels 204 connected to an axle 206 may form
a conductive pathway between the conductive components 200, 202 of
the route between the transmitting and receiving locations 106,
108. This conductive pathway can form a lower resistance pathway
for the transmitted current 300 to travel along in an electronic
circuit that includes the conductive components. For example, the
wheels and axles can short out the electronic circuit that includes
the power source that supplies the transmitted current, the
conductive components of the route, and the monitoring system. The
short or shunt created by the wheels and axles can result in the
transmitted current increasing to a larger, third magnitude 312 due
to the decrease in resistance in the circuit caused by the short.
For example, the power supply may supply approximately the same
voltage (e.g., by direct current or a time-varying voltage that is
an alternating current) to the conductive components at the
transmitting location, and the lower resistance of the circuit
causes the transmitting current to increase while the applied
voltage remains the same or substantially the same. The short or
shunt created by the wheels and axles can result in the received
current 302 decreasing to a smaller, fourth magnitude 314 due to
the decrease in transmitted current that is conducted in the
circuit to the receiving location. For example, more of the
transmitted current may not reach the receiving location due to the
short created by the vehicle system.
[0034] When the vehicle system 104 exits the examined segment 216
of the route 102 at a time of exit 318, the short created by the
vehicle system is no longer present in the circuit that includes
the conductive components 200, 202 of the route. As a result, the
transmitted current 300 may decrease back to the first magnitude
308 (e.g., due to the increased resistance of the circuit without
the short) and the received current 302 may increase back to the
second magnitude 310 (e.g., due to more of the transmitted current
being conducted to the receiving location 108 when the short is no
longer present). The monitoring system 100 can examine the
transmitted and/or received currents in order to determine when the
examined segment is occupied by the vehicle system.
[0035] The time period over which the vehicle system 104 travels
over the examined segment 216 of the route 102 (e.g., the time
between the time of entry 316 and time of exit 318) can be
relatively short, such as on the order of a few minutes or hours.
In accordance with one or more aspects of the inventive subject
matter described herein, the monitoring system 100 may additionally
or alternatively monitor the transmitted and/or received currents
300, 302 over longer periods of time in order to identify and/or
predict potential contamination or damage to the route and/or the
surface 110 on which the route is positioned. For example, changes
in the transmitted and/or received currents over extended periods
of time may indicate that the ballast material on which the route
is disposed may need to be cleaned and/or replaced, that the route
is damaged (e.g., one or more of the conductive components is
broken), that a foreign object is on the route, and the like.
[0036] As one example, the ballast material 112 on which the
conductive components 200, 202 of the route 102 are disposed may
become contaminated, such as with materials carried by the vehicle
systems that drip or fall onto the ballast material, the ballast
material corroding, the ballast material freezing or becoming at
least partially submerged in water, or the like. This contamination
may cause at least a contaminated portion 218 of the ballast
material to increase in conductivity (or otherwise decrease in
resistance). For example, the portion of the ballast material that
is contaminated may be coupled with the conductive components such
that this portion of the ballast material forms a pathway between
the conductive components that has a lower resistance that other
portions of the ballast material. As a result, at least some of the
transmitted current 300 that is injected into the conductive
components may be conducted between the conductive components by
the contaminated portion of the ballast material and not be sensed
as part of the receiving current 302 at the receiving location 108.
If enough current is conducted by the contaminated portion of the
ballast material, the monitoring system 100 may erroneously
determine that a vehicle system is present in the examined segment
216 of the route.
[0037] As another example, a portion 220 of one or more of the
conductive components 200, 202 of the route 102 may become damaged
(e.g., broken through an entire cross-sectional area of the
component or through a significant portion of the cross-sectional
area). This damage can reduce the amount of transmitted current 300
that is sensed at the receiving location 108 of the route as the
receiving current 302. If enough current is unable to be conducted
through the damaged portion 220 of the route, then the monitoring
system 100 may be unable to determine that a vehicle system 104 is
located within the examined section 216 of the route when the
vehicle system is present in the examined section of the route.
[0038] As another example, a foreign object may be positioned on
the route 102 between the conductive components 200, 202 of the
route. For example, a chain, bar, pipe, bicycle, or other at least
partially conductive object may fall onto the route so that the
object engages both of the conductive components of the route
within the examined section 216 of the route. The contaminated
portion 218 of the ballast material 212 shown in FIG. 2
alternatively may represent such an object. If this object has
sufficient conductivity, the object can form a pathway between the
conductive components that has a lower resistance than the
conductive components between the transmitting and receiving
locations 106, 108. As a result, at least some of the transmitted
current 300 that is injected into the conductive components may be
conducted between the conductive components by the foreign object
and not be sensed as part of the receiving current 302 at the
receiving location 108. If enough current is conducted by the
foreign object, the monitoring system 100 may erroneously determine
that a vehicle system is present in the examined segment 216 of the
route.
[0039] The above are just a few non-limiting examples of external
factors (e.g., causes other than the presence of the vehicle system
104 in the examined segment 216 of the route 102) that can change
the conductivity of a circuit that includes the conductive
components 200, 202 of the route between the transmitting and
receiving locations 106, 108. In order to prevent any such change
in the conductivity of the circuit from erroneously causing the
monitoring system 100 from correctly identifying the presence or
absence of the vehicle system in the examined segment of the route,
the monitoring system may examine changes in the transmitted and/or
received currents 300, 302 over time in order to predict or
identify these external factors modifying the transmitted and/or
received currents.
[0040] FIG. 4 illustrates examples of changes in the transmitted
current 300 that is injected into the conductive components of the
route at the transmitting location 106 along the route 102 and
changes in the received current 302 that is sensed by the
monitoring system at the receiving location 108 along the route
when the ballast material 112 on which the route is positioned
becomes contaminated. The transmitted and received currents are
shown alongside a horizontal axis 400 representative of time and a
vertical axis 402 representative of magnitudes of the transmitted
and received currents 302, 304. The horizontal axis shown in FIG. 4
differs from the horizontal axis 304 shown in FIG. 3 in that the
horizontal axis of FIG. 4 represents a much longer time period. For
example, the horizontal axis in FIG. 3 may represent time periods
of several minutes to few hours, while the horizontal axis in FIG.
4 can represent time periods extending over several days, weeks,
months, or years. The vertical axis shown in FIG. 4 may be
different from the vertical axis 306 shown in FIG. 3 in that the
vertical axis of FIG. 4 may encompass much smaller and larger
magnitudes of the transmitting and/or receiving currents.
[0041] The transmitted and received currents 300, 302 shown in FIG.
4 may be sampled by the monitoring system 100 at various times. For
example, instead of continuously measuring the transmitted and
received currents, the monitoring system may measure the
transmitted and/or received currents periodically (e.g., once every
second, every few seconds, every few minutes, every few hours,
every few days, or the like) or when directed by an operator or
other external event (e.g., a vehicle system leaving the examined
segment of the route). Alternatively, the transmitted and/or
received currents may be continuously measured by the monitoring
system.
[0042] As shown in FIG. 4, the transmitted current 300 gradually
increases over time from a first magnitude 404 and the received
current 302 gradually decreases over time from a second magnitude
406. The first and second magnitudes shown in FIG. 4 may correspond
to the corresponding first and second magnitudes 308, 310 shown in
FIG. 3. The increases in the transmitted current and/or the
decreases in the received current over the extended time period
shown in FIG. 4 can be identified by the monitoring system 100
(shown in FIG. 1) as being caused by an external factor other than
the presence of a vehicle system 104 (shown in FIG. 1).
[0043] The monitoring system 100 can distinguish between relatively
rapid rates of change in the transmitting and/or receiving currents
300, 302 and more gradual (e.g., slower) rates of change in the
transmitting and/or receiving currents. As shown in FIG. 4, both
the transmitting current and the receiving current exhibit faster
rates of change (e.g., corresponding increases or decreases) during
three corresponding time periods 408, 410, 412, but slower overall
rates of change between these time periods. The transmitting
current increases from the initial first magnitude 404 to an upper
threshold magnitude 414 while the receiving current decreases from
the initial second magnitude 406 to a lower threshold magnitude
416.
[0044] The monitoring system 100 can ignore the faster rates of
change during the time periods 408, 410, 412 but identify the
larger changes in the transmitting and receiving currents 300, 302
to the corresponding threshold magnitudes 414, 416 as indicative of
the ballast material 112 (shown in FIG. 1) becoming contaminated.
For example, if the monitoring system identifies an increase in the
transmitting current to the upper threshold magnitude 414 and/or a
decrease in the receiving current to the lower threshold magnitude
416, and this increase or decrease occurs over a relatively long
threshold time period (e.g., a time period that is longer than the
time period of inclement weather, a vehicle system traveling over
the examined segment of the route, or the like, such as several
days, weeks, or months), then the monitoring system can identify
the increase or decrease as being indicative of a contaminated
portion 218 of the ballast material, as shown in FIG. 2. The
smaller and/or more rapid rates of change in the transmitting
and/or receiving currents can be caused by a variety of temporary
external factors, such as wet weather conditions (e.g., the ballast
material 112 becomes wet or frozen between the conductive
components 200, 202 of the route 102). But, because these temporary
factors generally do not extend or continue on for the length of
time period over which the monitoring system monitors the
transmitting and/or receiving currents, the monitoring system can
distinguish between temporary changes in the transmitting and/or
receiving currents and longer term changes in the transmitting
and/or receiving currents.
[0045] In one aspect, a temporary change may occur when the
transmitting and/or receiving currents vary in value (e.g.,
magnitude, frequency, or the like) for a time period that is no
greater than a designated time period (e.g., one second, five
seconds, ten seconds, one minute, five minutes, ten minutes, or
another value). Changes in the currents that last at least as long
as this designated time period may not be temporary changes in the
currents. The length of the designated time period may be adjusted
to control the sensitivity of the monitoring system.
[0046] The upper and/or lower thresholds may be learned over time.
For example, when one examined segment of the route is later
identified as having contaminated ballast that is conducting
current between the conductive components of the route, the
transmitted and/or received currents at which the ballast material
is identified as being contaminated may be recorded. This same
procedure may be repeated for several segments of one or more
routes. The recorded values may be referred to as failure values.
An average, median, or other calculation of these values may be
used as one or more of the upper and/or lower thresholds. As
additional segments have ballast material that becomes
contaminated, these thresholds may be updated.
[0047] Additionally or alternatively, the weather conditions at or
near the monitoring system 100 may be taken into account when
examining the transmitted and/or received currents. For example,
during wet weather (e.g., rain, snow, sleet, or the like), the
resistance of the circuit that includes the conductive components
200, 202 of the route 102 may decrease and/or one or more shorts
may form in the ballast material 112 between these conductive
components 200, 202 (e.g., by pools of moisture in the ballast
material). The system 100 may ignore changes in the transmitted
current and/or received current during such weather conditions, as
these changes may not be indicative of longer term changes or
contamination of the ballast material 112.
[0048] The monitoring system 100 can determine that at least a
portion of the ballast material 112 that contacts the conductive
components 200, 202 of the route 102 is at least partially
conducting the transmitted current 300 between the conductive
components when the transmitted current increases and/or the
received current decreases over a time period that is longer than a
time period during which a vehicle system 104 travels or would
travel over the route 102 from the transmitting location 106 to the
receiving location 108 (or from the receiving location to the
transmitting location). The time period during which the vehicle
system travels or would travel over this length of the route can be
calculated based on the distance between the transmitting and
receiving locations and a designated speed of the vehicle system.
The designated speed can be a lower speed limit of the route in the
examined section 216, such as a minimum speed that the vehicle
system is required to travel according to rule, regulation, law, or
otherwise.
[0049] For example, if the distance between the transmitting
location and the receiving location is two miles (e.g., 3.2
kilometers) and the lower speed limit of the route in this segment
is twenty miles per hour (e.g., 32 kilometers per hour), then the
time period over which a vehicle system should travel over this
examined segment or is expected to travel over the examined segment
is six minutes. If the monitoring system determines that the
transmitted current continues to increase over a longer time period
and/or that the received current continues to decrease over a
longer time period, then the monitoring system can determine that a
portion of the ballast material between the conductive components
of the route is at least partially conducting electric current
between the conductive components (e.g., is forming a short or a
shunt).
[0050] The monitoring system can ignore temporary smaller and/or
more rapid rates of change in the currents 300, 302, such as the
increases or decreases during the time periods 408, 410, 412. These
changes can be ignored by the monitoring system because the
corresponding increase or decrease in magnitude of the transmitting
and/or receiving current is not sufficiently large to exceed the
corresponding upper or lower threshold 414, 416, and/or because the
rate of change in the currents is faster than a threshold rate of
change. For example, even if the transmitting current increases
above the upper threshold magnitude and/or the receiving current
falls below the lower threshold magnitude, if the increase or
decrease in the corresponding current occurs over too short of a
time period (e.g., less than a threshold time period), then the
monitoring system can disregard the change as being caused by a
temporary condition, such as the weather. Increases and/or
decreases in the transmitting and/or receiving currents above or
below the threshold magnitudes 414, 416 can be identified by the
monitoring system as being caused by a contaminated portion 218
(shown in FIG. 2) of the ballast material 112 (also shown in FIG.
2) when the increases and/or decreases occur over a longer period
of time, such as a threshold period of time 418. Additionally or
alternatively, the weather conditions at the monitoring system 100
can be monitored to determine if the temporary changes in the
transmitted and/or received currents are at least partially caused
by shorts formed from rain, snow, sleet, or the like, between the
conductive components of the route.
[0051] FIG. 5 illustrates examples of changes in the transmitted
current 300 that is injected into the conductive components of the
route at the transmitting location 106 along the route 102 and
changes in the received current 302 that is sensed by the
monitoring system at the receiving location 108 along the route
when a foreign object extends across the conductive components 200,
202 of the route. The transmitted and received currents are shown
alongside the horizontal axis 304 and the vertical axis 306
described above. The transmitted and received currents may be
sampled by the monitoring system at various times, similar to as
described above. Alternatively, the transmitted and/or received
currents may be continuously measured by the monitoring system.
[0052] As shown in FIG. 5, the transmitted current 300 abruptly
increases from the initial first magnitude 308 (e.g., the current
applied to the conductive components 200, 202 of the route 102, as
described above) to a larger second magnitude 500 at a first time
502 within a relatively short time period, such as within a few
seconds or less than one second. The received current 302 similarly
decreases from the initial second magnitude 310 (e.g., as described
above) to zero current or approximately zero current within the
same relatively short time period and/or at the same time 502 that
the transmitted current abruptly increases to the second magnitude
500.
[0053] Following the abrupt changes in the transmitted and/or
received currents 300, 302, the transmitted and received currents
remain at or approximately at the same magnitudes for an extended
period of time, such as several minutes, hours, or days. This
extended period of time can be much longer than the time period
over which the transmitted and/or received currents increased to
the magnitude 400 or decreased to zero (or approximately zero)
current. For example, the transmitted and received currents can
maintain constant or approximately constant values for a time
period that is several orders of magnitude longer than the time
period over which the transmitted and/or received currents abruptly
changed. The transmitted and received currents may be
"approximately" constant when changes in the currents occur over
relatively short time periods and are more indicative of noise in
the sampling or measurements of the currents than other causes.
[0054] The monitoring system 100 can determine that a foreign
object is connecting the conductive components 200, 202 of the
route 102 (as described above) responsive to identifying the abrupt
increase in the transmitted current 300 and/or the abrupt decrease
or elimination of the received current 302. Additionally or
alternatively, the monitoring system 100 can determine that the
foreign object is connecting the conductive components of the route
responsive to (a) identifying the abrupt increase in the
transmitted current and/or the abrupt decrease or elimination of
the received current, and (b) determining that the transmitted
current remains constant or approximately constant for at least a
threshold, non-zero period of time following the abrupt increase
and/or determining that the received current remains at or
approximately at zero current for at least the threshold, non-zero
period of time following the abrupt decrease. The monitoring system
can determine that the transmitted and/or receive currents remain
constant or approximately constant for at least the threshold,
non-zero period of time when the changes in the currents last for
relatively short periods of time and/or occur at approximately the
same or the same time, as is the case for the changes 504, 506 and
the changes 508, 510 shown in FIG. 5.
[0055] In one aspect, the monitoring system 100 may detect
temporary fluctuations or changes 504, 506, 508, 510 in the
transmitted and received currents 300, 302 following the abrupt
increase and/or decrease in the transmitted and/or received
currents. These changes may be larger than noise in the currents
that are sensed, and may occur over a relatively smaller period of
time. For example, the changes may have magnitudes that are larger
than the standard deviation (or another statistical measure or
calculation) of the measured current during time periods that
follow the abrupt increase or decrease in the current.
[0056] The monitoring system can determine whether the temporary
changes occur at the same or approximately same time. For example,
the monitoring system can determine that the changes 504, 506 in
the transmitted and received currents occur at the same or
approximately the same time and that the changes 508, 510 in the
transmitted and received currents occur at the same or
approximately the same time. When the changes 504, 506 and 508, 510
in the transmitted and received currents occur at the same or
approximately same time (e.g., the temporary change in the
transmitted current occurs during a time period that is the same as
or overlaps with a time period during which the temporary change in
the received current occurs), the monitoring system may confirm
that a foreign object is connecting (e.g., shorting out) the
conductive components 200, 202 of the route 102. For example, the
temporary changes occurring in the same current may be caused by
relatively small movements of the foreign object (e.g., vibration
of a conductive body on the tracks due to wind or movement of
another nearby vehicle system). Because the same foreign object
engages both conductive components to cause the abrupt changes in
the transmitted and received currents shown in the example of FIG.
5, temporary movements of the foreign object may be represented by
the temporary changes occurring at the same time or approximately
the same time in the transmitted and received currents.
[0057] FIG. 6 illustrates examples of changes in the transmitted
current 300 that is injected into the conductive components of the
route at the transmitting location 106 along the route 102 and
changes in the received current 302 that is sensed by the
monitoring system at the receiving location 108 along the route
when one or more of the conductive components 200, 202 of the route
are damaged or broken. One or more of these conductive components
can be broken when the conductive component is cut or separated
through an entire cross-sectional area of the conductive component.
For example, a rail of a track is completely broken when a segment
of the rail that previously was a continuous or contiguous section
of the rail is separated into two separate sections spaced apart by
a gap. A conductive component of the route can be damaged when the
conductive component is cut or separated through part, but less
than all, of the entire cross-sectional area of the conductive
component. For example, a rail of a track is damaged but not broken
when a segment of the rail is partially separated into two separate
sections, but is still at least partially connected.
[0058] The transmitted and received currents 300, 302 are shown in
FIG. 6 alongside the horizontal axis 304 and the vertical axis 306
described above. The transmitted and received currents may be
sampled by the monitoring system at various times, similar to as
described above. Alternatively, the transmitted and/or received
currents may be continuously measured by the monitoring system.
[0059] As shown in FIG. 6, both of the transmitted and received
currents 300, 302 abruptly decrease at a time 600. The transmitted
current may decrease from the initial first magnitude 308 (e.g.,
the current applied to the conductive components 200, 202 of the
route 102, as described above) to a smaller second magnitude 602
within a relatively short time period, such as within a few seconds
or less than one second. The received current 302 also abruptly
decreases from the initial second magnitude 310 (e.g., as described
above) to zero current or approximately zero current within the
same relatively short time period and/or at the same time 600. In
the illustrated example, the transmitted current decreases to the
second magnitude 602 which is larger than the initial magnitude 310
of the received current, but alternatively may decrease to a second
magnitude that is smaller than the initial magnitude of the
received current. The time 600 may indicate when one or more of the
conductive components were damaged or broken.
[0060] Following the abrupt changes in the transmitted and/or
received currents 300, 302, the transmitted and received currents
remain at or approximately at the same magnitudes for an extended
period of time, such as several minutes, hours, or days. This
extended period of time can be much longer than the time period
over which the transmitted and/or received currents decreased at
the time 600. For example, the transmitted and received currents
can maintain constant or approximately constant values for a time
period that is several orders of magnitude longer than the time
period over which the transmitted and/or received currents abruptly
decreased. The transmitted and received currents may be
"approximately" constant when changes in the currents occur over
relatively short time periods and are more indicative of noise in
the sampling or measurements of the currents than other causes.
[0061] In the illustrated example, the received current 302 is
eliminated or substantially eliminated at the time 600. For
example, following the time 600, the monitoring system 100 may no
longer detect or sense any received current at the receiving
location 108 along the route 102 (as shown in FIG. 1). While the
monitoring system may detect or sense some current at the receiving
location due to noise or hysteresis, the monitoring system may not
detect or sense a measurable received current. This lack of
detection of the received current following the time 600 can
indicate that one or more of the conductive components 200, 202 in
the route was damaged or broken at the time 600. For example, the
monitoring system may no longer be able to detect the received
current because a break in a rail or significant damage to the rail
may prevent the received current from being detected in the
receiving location 108 of the route. Although the monitoring system
may be monitoring the route at plural terminals 212, 214 (shown in
FIG. 2), the received current that is measured may be a difference
between the currents sensed at these terminals 212, 214 or
otherwise indicative of the electric energy sensed at these
terminals 212, 214 such that the break or damage in one of the
conductive components 200 or 202 causes the received current to be
eliminated, as shown in FIG. 6.
[0062] The monitoring system 100 can determine that one or more of
the conductive components 200, 202 is broken or damaged responsive
to identifying the abrupt decrease in the transmitted current 300
and/or the abrupt decrease or elimination in the received current
302 at the same time 600 or at approximately the same time.
Additionally or alternatively, the monitoring system can determine
that one or more of the conductive components 200, 202 is broken or
damaged responsive to identifying the elimination in the received
current 302, regardless of changes in the transmitted current
300.
[0063] In one aspect, the monitoring system 100 may distinguish
between a foreign object being on the route 102 (e.g., described
above in connection with the example shown in FIG. 5) from a break
or damage to the conductive component 200 and/or 202 in the route
based on the presence or absence in the intermittent temporary
changes 504, 506, 508, 510 in the transmitted and/or received
currents 300, 302. For example, if no intermittent and temporary
changes are sensed in the transmitted and/or received currents 300,
302, then the monitoring system can determine that the route has
been broken or damaged. If intermittent and temporary changes
occurring at the same or approximately same time in the transmitted
and received currents are sensed, then the monitoring system may
determine that there is a foreign object on the route. Additionally
or alternatively, the monitoring system may distinguish between a
foreign object on the route and damage or a break in the route
based on whether the transmitted current increases or decreases
when the received current decreases. If both the transmitted and
received currents decrease at the same time or approximately the
same time, then the monitoring system may determine that the route
is broken or damaged. If the transmitted current increases while
the received current decreases, the monitoring system may determine
that a foreign object is on the route.
[0064] The monitoring system 100 may distinguish between (a)
contamination of the ballast material 112 (shown in FIG. 1 and
described above in connection with the example shown in FIG. 4) and
(b) a foreign object on the route 102 (e.g., described above in
connection with the example of FIG. 5) or damage or a break in the
route (e.g., described above in connection with FIG. 6) based on
the trends in the transmitted and/or received currents 300, 302.
For example, the increases in the transmitted current and/or the
decreases in the received current that can occur when the ballast
material is contaminated may occur over much longer time periods
(e.g., days, weeks, months, or years) than the increases or
decreases in the transmitted and/or received currents when a
foreign object is on the route and/or the route is broken or
damaged.
[0065] The monitoring system 100 can distinguish between the
presence of the vehicle system 104 (shown in FIG. 1) on the route
102 (described above in connection with FIG. 3) and contamination
of the ballast material 112 (described above in connection with
FIG. 4) based on the trends in the transmitted and/or received
currents 300, 302. For example, the increases in the transmitted
current and/or the decreases in the received current that can occur
when the ballast material is contaminated may occur over much
longer time periods (e.g., days, weeks, months, or years) than the
increases or decreases in the transmitted and/or received currents
when the vehicle system is in the examined segment of the
route.
[0066] The monitoring system 100 can distinguish between the
presence of the vehicle system 104 (shown in FIG. 1) on the route
102 (described above in connection with FIG. 3) and a foreign
object being on the route 102 (described above in connection with
FIG. 5) based on the change in the received current 302, the
duration of the changes in the transmitted and/or received currents
300, 302, and/or the temporal correlation between the temporary
changes 504, 506 and 508, 510 (shown in FIG. 5). For example, the
received current may not decrease to zero current or approximately
zero current when the vehicle system is detected on the route, but
may decrease to zero current or approximately zero current when the
foreign object is on the route. The transmitted and/or received
currents may respectively increase and decrease for a shorter
period of time when the vehicle system is detected on the route
than when the foreign object is on the route. For example, the
transmitted current may increase and the received current may
decrease and remain increased or decreased until the foreign object
is removed. The temporary changes in the transmitted and received
currents may not occur at the same or approximately same times
(e.g., which indicates temporal correlation between the temporary
changes) when the vehicle system is detected on the route, but may
occur when a foreign object is on the route.
[0067] The problems or faults that may be identified or predicted
by the monitoring system 100 are not limited to those problems or
faults described herein. For example, changes in the transmitted
current and/or received current may be associated with other
faults. Over time, historical changes in the transmitted current
and/or received current can be associated with various problems or
faults with examined segment 216 of the route 102. These historical
changes can be compared with newly obtained transmitted currents
and/or received currents in order to determine if the changes in
the newly obtained transmitted currents and/or received currents
more closely match one or more of the historical changes. If so,
then the problems or faults associated with the historical changes
that match the newly obtained currents may be identified as a
problem or fault. For example, additional failures such as foreign
currents interfering with a circuit that includes the conductive
components of the route (e.g., currents coming from faults on an
adjacent electrified segment of the route, a defective cathodic
protection system on a buried pipeline, or the like), defective
insulated joints of the route, or other problems may be identified
by comparing the transmitted currents and/or received currents with
historical data.
[0068] FIG. 7 is another schematic illustration of the monitoring
system 100 shown in FIG. 1. The example of the monitoring system in
FIG. 7 provides additional details about components that may be
included in the monitoring system in one embodiment. The monitoring
system includes or is connected with a power source 700, such as
one or more utility power grids, batteries, fuel cells, capacitors,
flywheels, generators, alternators, or other sources of electric
current. The power source provides electric current that is applied
to the conductive components 200, 202 of the route 102 in the
transmitting location 106 by the monitoring system.
[0069] A transmit controller 702 of the monitoring system controls
the electric current that is applied to the route by the power
source. The transmit controller includes or represents hardware
circuits or circuitry that includes or is connected with one or
more processors or other electronic logic-based devices that
operate to perform the functions of the transmit controller. The
transmit controller can control the magnitude (e.g., volts, amps,
power, or the like), waveform, frequency, or the like, of the
transmit current supplied from the power source, such as by
operating one or more switches or other devices that are included
in or coupled with the transmit controller.
[0070] A transmit monitor 704 of the monitoring system measures the
transmitted current that is applied to the route by the power
source. The transmit monitor includes or represents hardware
circuits or circuitry that includes or is connected with one or
more processors or other electronic logic-based devices that
operate to perform the functions of the transmit monitor. The
transmit monitor can be coupled with the route at the same
terminals 208, 210 where the transmit current is applied to the
route, and/or can be coupled with the route in another location in
order to measure the transmit current. In one aspect, the transmit
monitor can include a voltmeter, amp meter, or combination thereof,
that measures the transmit current.
[0071] A memory 706 of the monitoring system includes one or more
devices that can store the transmit currents measured by the
transmit monitor. For example, the memory can include one or more
computer hard drives, flash drives, magnetic tapes, optical discs,
or the like. The memory can store the measured transmit currents
over time for analysis or examination.
[0072] A communication device 708 of the monitoring system includes
transceiver hardware and/or circuitry that includes or is connected
with one or more transceiver devices 710 (e.g., an antenna, modem,
or the like) that communicate signals with one or more other
communication devices. In the illustrated example, the transceiver
device is an antenna that wirelessly communicates (e.g., transmits,
broadcasts, and/or receives) signals. Optionally, the transceiver
device may be coupled with one or more conductive pathways 718
(e.g., cables, catenaries, rails, or the like) to communicate
signals through the conductive pathways.
[0073] A sensor 712 of the monitoring system is coupled with the
route in the receiving location 108 to measure the received
currents conducted through the conductive components of the route.
The sensor may include or represent a voltmeter, amp meter, or
combination thereof, that measures the receive current. The sensor
can be connected with the route by the terminals 212, 214.
[0074] A receive monitor 714 of the monitoring system measures the
received current that is conducted through the conductive
components of the route. The receive monitor is connected with the
sensor to monitor the received current. The receive monitor can
include or represent hardware circuits or circuitry that includes
or is connected with one or more processors or other electronic
logic-based devices that operate to perform the functions of the
receive monitor.
[0075] Another memory 716 of the monitoring system includes one or
more devices that can store the received currents measured by the
receive monitor. For example, the memory can include one or more
computer hard drives, flash drives, magnetic tapes, optical discs,
or the like. The memory can store the measured received currents
over time for analysis or examination. In one embodiment, the
memories 706, 716 can be combined into a single memory.
[0076] Another communication device 720 of the monitoring system
includes transceiver hardware and/or circuitry that includes or is
connected with one or more transceiver devices 722 (e.g., an
antenna, modem, or the like) that communicate signals with one or
more other communication devices. In the illustrated example, the
transceiver device is an antenna that wirelessly communicates
(e.g., transmits, broadcasts, and/or receives) signals. Optionally,
the transceiver device may be coupled with the one or more
conductive pathways 718 (e.g., cables, catenaries, rails, or the
like) to communicate signals through the conductive pathways. The
communication devices 708, 720 can communicate with each other so
that the transmitted and/or received currents can be stored in one
or more of the memories 706, 716, and/or for the transmit monitor
and/or receive monitor to track changes in the transmitted and/or
received currents.
[0077] The transmit monitor and/or receive monitor can monitor the
transmitted and/or received currents as described above in order to
determine when a vehicle system 104 (shown in FIG. 1) enters into
the examined segment 216 of the route, when the ballast material
112 (shown in FIG. 1) needs to be cleaned or replaced, when a
foreign object is on the route, when the route is broken or
damaged, and the like. The communication devices can be used so
that the transmit monitor is aware of the received currents and/or
the receive monitor is aware of the transmitted currents.
Optionally, only one of the transmit monitor or the receive monitor
examines the transmitted and received currents to determine when a
vehicle system enters into the examined segment of the route, when
the ballast material needs to be cleaned or replaced, when a
foreign object is on the route, when the route is broken or
damaged, and the like. Additionally or alternatively, one or more
of the transmit monitor or the receive monitor may be disposed at a
remote location for remotely examining the transmitted and/or
received currents as described above in order to determine when a
vehicle system enters into the examined segment of the route, when
the ballast material needs to be cleaned or replaced, when a
foreign object is on the route, when the route is broken or
damaged, and the like.
[0078] In the illustrated example, the examined segment 216 of the
route 102 is between additional segments 724, 726 of the route. The
segments 216, 724, 726 are spaced apart from each other by
electrically insulative gaps 728. The insulative gaps prevent the
conductive components in the neighboring segments of the route from
being conductively coupled with each other. The neighboring
segments 724, 726 also may be connected with separate monitoring
systems that are similar to the monitoring system 100 described
herein. Each of these monitoring systems can examine the
transmitted and/or received currents in order to determine when a
vehicle system enters into the corresponding segment of the route,
when the ballast material beneath the corresponding segment of the
route needs to be cleaned or replaced, when a foreign object is on
the route in the corresponding segment, when the corresponding
segment of the route is broken or damaged, and the like, as
described above.
[0079] In one embodiment, two or more of the monitoring systems
that monitor different segments of the route can communicate with
each other in order to identify causes of changes in the
transmitted and/or received currents. For example, a first
monitoring system that is located upstream of a second monitoring
system along the route can communicate with the second monitoring
system in order to determine if changes in transmitted and received
currents represent the movement of a vehicle system along route, a
foreign object on the route, damage or a break in the route, or the
like. The monitoring systems can communicate the transmitted and
received currents with each other. If the transmitted and received
currents measured by the monitoring systems change in a serial or
sequential manner, then the changes in the transmitted and received
currents may indicate movement of a vehicle system instead of
another cause.
[0080] FIG. 8 illustrates transmitted and received currents 804,
806 that are measured by several monitoring systems 100 connected
with different segments of the same route in accordance with one
embodiment. The currents 804, 806 are shown alongside a horizontal
axis 800 representative of time and vertical axes 802
representative of magnitudes of the transmitted and received
currents.
[0081] The transmitted and received currents 804A, 806A are
measured by a first monitoring system 100 that is coupled with a
first segment of the route 102, the transmitted and received
currents 804B, 806B are measured by a second monitoring system 100
that is coupled with a second segment of the route 102 located
downstream from the first segment along a direction of travel of a
vehicle system, the transmitted and received currents 804C, 806C
are measured by a third monitoring system 100 that is coupled with
a third segment of the route 102 located downstream from the second
segment along a direction of travel of a vehicle system, and the
transmitted and received currents 804D, 806D are measured by a
fourth monitoring system 100 that is coupled with a fourth segment
of the route 102 located downstream from the third segment along a
direction of travel of a vehicle system. Additional or fewer
monitoring systems and segments may be used.
[0082] As a vehicle system 104 travels along the route 102, the
monitoring systems detect changes 808, 810 in the transmitted and
received currents 804, 806, as described above in connection with
FIG. 3. As shown in FIG. 8, these changes 808, 810 occur
sequentially among the different segments and monitoring systems.
These sequentially spaced changes 808, 810 can indicate that the
vehicle system is moving along the route, with the vehicle system
traveling over the first segment during a first time period 812,
over the second segment during a second time period 814, over the
third segment during a third time period 816, and over the fourth
segment during a fourth time period 818.
[0083] The monitoring systems can communicate the transmitted and
received currents 804, 806 with each other (and/or another signal
that indicates the presence of the vehicle system in the segments
of the route being monitored by the monitoring systems) so that the
monitoring systems can distinguish between changes in the
transmitted and received currents that represent the presence of
the vehicle system versus other causes in the changes. For example,
changes in the transmitted and received currents caused by
contaminated ballast material 112 may not sequentially occur among
the different segments of the route, changes in the transmitted and
received currents caused by a foreign object on the route may not
sequentially occur among the different segments of the route, and
changes in the transmitted and received currents caused by damage
or a break in the route may not sequentially occur among the
different segments of the route. The monitoring systems can
communicate with each other to avoid incorrectly identifying
movement of a vehicle system with contaminated ballast material, a
foreign object on the route, damage to the route, a break in the
route, or the like.
[0084] FIGS. 9A and 9B illustrate a flowchart of a method 900 for
monitoring a segment of a route in accordance with one embodiment
of the inventive subject matter. The method may be used by the
monitoring system 100 (shown in FIG. 1) to monitor the examined
segment 216 (shown in FIG. 2) of the route 102 (shown in FIG. 1).
Although several different monitoring methodologies are described
and shown herein, the monitoring system and method may use several
or all of these methodologies at the same time.
[0085] At 902, electric current is applied to conductive components
of a route as a transmitted current. This current can be an
alternating current, a direct current, or another type of current.
At 904, the transmitted current is monitored. For example, the
amps, voltage, frequency, or other characteristic of the
transmitted current may be measured or otherwise tracked over time
in order to identify changes in the transmitted current.
[0086] At 906, current that is conducted along the conductive
components of the route to a receiving location is monitored as a
received current. For example, the amps, voltage, frequency, or
other characteristic of the transmitted current may be measured or
otherwise tracked over time in order to identify changes in the
received current.
[0087] At 908, a determination is made as to whether the
transmitted current increased and then decreased and/or the
received current decreased and then increased within a relatively
short time period. For example, as shown above in the example of
FIG. 3, the travel of a vehicle system along the examined segment
of the route can cause the transmitted current to increase at the
same time or approximately the same time that the received current
decreases, followed by the transmitted current decreasing at the
same or approximately the same time that the received current
increases, within a relatively short period of time. In the event
of these changes to the transmitted and received currents, the
monitoring system may determine that a vehicle system is located in
or has traveled over the examined segment of the route. As a
result, flow of the method 900 continues to 910. On the other hand,
if the transmitted current and/or received current does not change
in this way, then the monitoring system may determine that the
changes in the transmitted current and/or received current do not
indicate the presence of a vehicle system in the examined section
of the route. As a result, flow of the method 900 proceeds to
912.
[0088] At 910, the presence of the vehicle system in the examined
segment of the route is identified by the monitoring system. The
monitoring system can report this presence of the vehicle system to
one or more other locations, such as another monitoring system (as
described above), to a signal to warn other vehicle systems of the
presence of the vehicle system on the examined segment of the
route, or the like. At 924, the monitoring system can take one or
more remedial or responsive actions, such as reporting the presence
of the vehicle system to another location.
[0089] At 912, a determination is made as to whether the
transmitted current increases and the received current decreases
for an extended period of time, and/or if intermittent temporary
changes in the transmitted current are temporally correlated with
similar changes in the received current. For example, as described
above in connection with the example of FIG. 5, the monitoring
system may determine if the transmitted current increases and the
received current decreases (or is substantially eliminated) at the
same time or approximately the same time. The monitoring system
also may determine if temporary changes 504, 506, 508, 510 in the
transmitted and received currents occur at the same time or
approximately the same time. If the monitoring system identifies
such changes in the transmitted and received currents, the changes
may indicate a foreign object is connected to the conductive
components of the route and may be shorting out the circuit that
includes the conductive components. As a result, flow of the method
900 may proceed to 914. Otherwise, the changes in the currents may
not indicate the presence of a foreign object, and flow of the
method 900 can proceed to 916.
[0090] At 914, a foreign object is identified as connecting the
conductive components of the route by the monitoring system. At
924, the monitoring system can take one or more remedial or
responsive actions, such as reporting the presence of the foreign
object to another location to schedule or request that an operator
or maintainer travel to the location of the examined segment of the
route to remove the foreign object. Optionally, the monitoring
system can communicate a signal to other vehicle systems or signals
to warn the vehicle systems or change the status of the signal to
prevent travel of the vehicle systems onto the examined segment of
the route.
[0091] At 916, a determination is made as to whether the
transmitted current and the received current decrease. For example,
the monitoring system may determine whether the transmitted current
decreases and the received current decreases (or is eliminated) at
the same time or approximately the same time. These changes in the
transmitted current and received current may indicate that the
route is damaged or broken within the examined segment, as
described above in connection with FIG. 6. In one aspect, the
monitoring system may determine if the transmitted current
decreases and the received current reduces to zero (or
approximately zero) current for an extended period of time, such as
several minutes or hours. If the monitoring system identifies these
changes in the transmitted and/or received currents, the monitoring
system can determine that the route has been damaged or broken. As
a result, flow of the method 900 may proceed to 918. On the other
hand, if these changes are not identified, then the transmitted
currents and received currents may not indicate that the route is
damaged or broken. As a result, flow of the method 900 can proceed
to 920.
[0092] At 918, the examined segment of the route is identified as
being broken or damaged, as described above, by the monitoring
system. At 924, the monitoring system can take one or more remedial
or responsive actions, such as reporting the damage or break in the
route to another location to schedule or request that an operator
or maintainer travel to the location of the examined segment of the
route to repair or examine the route. Optionally, the monitoring
system can communicate a signal to other vehicle systems or signals
to warn the vehicle systems or change the status of the signal to
prevent travel of the vehicle systems onto the examined segment of
the route.
[0093] At 920, a determination is made as to whether the
transmitted current demonstrates an increasing trend and/or the
received current demonstrates a decreasing trend over an extended
period of time. For example, the monitoring system can examine the
transmitted current and/or the received current over one or more
hours, days, weeks, months, or years in order to determine if the
transmitted current is gradually increasing while the received
current also is gradually decreasing. If the transmitted current is
exhibiting such an increasing trend and/or the receiving current is
exhibiting such a decreasing trend over an extended time period,
then these trends in the transmitted and received currents may
indicate that the ballast material beneath the conductive
components of the route is forming a short or shunt that is at
least partially conducting current between the conductive
components. As a result, flow of the method 900 can proceed to 922.
On the other hand, if the transmitted current is not exhibiting
such an increasing trend and/or the received current is not
exhibiting such a decreasing trend, then the transmitted and
received currents may not indicate that the ballast material is
forming a short or shunt. As a result, flow of the method 900 can
return to 902.
[0094] At 922, the monitoring system can identify the ballast
material as being contaminated in that the ballast material is at
least partially conducting current between the conductive
components of the route. At 924, the monitoring system can take one
or more remedial or responsive actions, such as reporting the
contaminated portion of the ballast material to another location to
schedule or request that an operator or maintainer travel to the
location of the examined segment of the route to replace, clean, or
otherwise repair the ballast material. Optionally, the monitoring
system can communicate a signal to other vehicle systems or signals
to warn the vehicle systems or change the status of the signal to
prevent travel of the vehicle systems onto the examined segment of
the route. In one aspect, the monitoring system can communicate a
request to an off-board location that the examined segment of the
route be repaired, such as by adding a resistive element (e.g., one
or more resistors), in order to change the electric characteristics
of the circuit that includes the conductive components of the route
in the examined segment of the route. Adding such a resistive
element can reduce or eliminate the increasing trend in the
transmitted current and/or the decreasing trend in the received
current.
[0095] In one embodiment, a wayside monitoring method includes
monitoring a transmitted current that is injected into conductive
components of a route that is traveled by one or more vehicle
systems, monitoring a received current that represents at least a
portion of the transmitted current that is conducted through the
conductive components of the route, examining changes in one or
more of the transmitted current or the received current over time
to determine when at least one of the vehicle systems is disposed
on the route between a first location along the route where the
transmitted current is injected into the conductive components and
a different, second location along the route where the received
current is monitored, and examining the same changes in the one or
more of the transmitted current or the received current to identify
at least one of a contaminated portion of a surface on which the
conductive components of the route are disposed, to identify a
foreign object other than the one or more vehicle systems that is
contacting the conductive components of the route, or to identify a
damaged or broken portion of at least one of the conductive
components of the route.
[0096] In one aspect, the changes that are examined to both
determine when at least one of the vehicles is disposed on the
route and to identify the at least one of the contaminated portion,
the foreign object, or the damaged or broken portion of the at
least one of the conductive components of the route include
increases or decreases in the transmitted current and the received
current and time periods over which the increases or decreases in
the transmitted current and the received current occur.
[0097] In one aspect, the contaminated portion of the surface
includes a portion of ballast material disposed beneath the
conductive components of the route that at least partially conducts
the transmitted current between the conductive components of the
route through the contaminated portion of the surface.
[0098] In one aspect, the foreign object that is identified is one
or more conductive bodies forming a short between the conductive
components of the route.
[0099] In one aspect, the damaged or broken portion of the at least
one of the conductive components of the route includes a portion of
the at least one of the conductive components that is separated
through an entire cross-sectional area of the at least one of the
conductive components.
[0100] In one aspect, the contaminated portion of the surface on
which the conductive components of the route are disposed is
identified when the changes in the transmitted current and in the
received current include an increasing trend in the transmitted
current over an extended period of time that concurrently occurs
with a decreasing trend in the received current over the extended
period of time.
[0101] In one aspect, the foreign object is identified when the
changes in the received current include a decrease in the received
current to zero current or approximately zero current and temporary
changes in the received current that are temporally correlated with
temporary changes in the transmitted current.
[0102] In one aspect, the damaged or broken portion of the at least
one of the conductive components of the route is identified when
the changes in the transmitted current and in the received current
include a decrease in the transmitted current that occurs
concurrently with an elimination of the received current.
[0103] In one aspect, the route includes a track over which rail
vehicles travel and the conductive components include rails of the
track.
[0104] In another embodiment, a wayside monitoring system includes
a transmit monitor and a receive monitor. The transmit monitor
includes one or more processors configured to measure a transmitted
current that is injected into conductive components of a route that
is traveled by one or more vehicle systems. The receive monitor
includes one or more processors (which may be one or more of the
same processors as the transmit monitor or different processors
than the transmit monitor) that are configured to measure a
received current that represents at least a portion of the
transmitted current that is conducted through the conductive
components of the route. At least one of the transmit monitor or
the receive monitor also is configured to examine changes in one or
more of the transmitted current or the received current over time
to determine when at least one of the vehicle systems is disposed
on the route between a first location along the route where the
transmitted current is injected into the conductive components and
a different, second location along the route where the received
current is monitored. At least one of the transmit monitor or the
receive monitor is configured to examine the same changes in the
one or more of the transmitted current or the received current to
identify at least one of a contaminated portion of a surface on
which the conductive components of the route are disposed, to
identify a foreign object other than the one or more vehicle
systems that is contacting the conductive components of the route,
or to identify a damaged or broken portion of at least one of the
conductive components of the route.
[0105] In one aspect, at least one of the transmit monitor or the
receive monitor is configured to examine the changes in the
transmitted current and in the received current to both determine
when at least one of the vehicles is disposed on the route and to
identify the at least one of the contaminated portion, the foreign
object, or the damaged or broken portion by identifying: (a)
increases or decreases in the transmitted current and the received
current and (b) time periods over which the increases or decreases
in the transmitted current and the received current occur.
[0106] In one aspect, at least one of the transmit monitor or the
receive monitor is configured to identify the contaminated portion
of the surface as a portion of ballast material disposed beneath
the conductive components of the route that at least partially
conducts the transmitted current between the conductive components
of the route through the contaminated portion of the surface.
[0107] In one aspect, at least one of the transmit monitor or the
receive monitor is configured to identify the foreign object as one
or more conductive bodies forming a short between the conductive
components of the route.
[0108] In one aspect, at least one of the transmit monitor or the
receive monitor is configured to identify the damaged or broken
portion of the at least one of the conductive components of the
route as a portion of the at least one of the conductive components
that is separated through an entire cross-sectional area of the at
least one of the conductive components.
[0109] In one aspect, at least one of the transmit monitor or the
receive monitor is configured to identify the contaminated portion
of the surface responsive to the changes in the transmitted current
and in the received current including an increasing trend in the
transmitted current over an extended period of time that
concurrently occurs with a decreasing trend in the received current
over the extended period of time.
[0110] In one aspect, at least one of the transmit monitor or the
receive monitor is configured to identify the foreign object
responsive to the changes in the received current including a
decrease in the received current to zero current or approximately
zero current and temporary changes in the received current being
temporally correlated with temporary changes in the transmitted
current.
[0111] In one aspect, at least one of the transmit monitor or the
receive monitor is configured to identify the damaged or broken
portion of the at least one of the conductive components of the
route is identified responsive to the changes in the transmitted
current and in the received current including a decrease in the
transmitted current that occurs concurrently with an elimination of
the received current.
[0112] In one aspect, the route includes a track over which rail
vehicles travel and the conductive components include rails of the
track.
[0113] In another embodiment, a wayside monitoring method includes
measuring a transmitted current that is applied to a conductive
rail of a track over which one or more rail vehicles travel at a
first location and measuring a received current at a different,
second location to the conductive rails of the track. The received
current includes at least a portion of the transmitted current that
is conducted through one or more of the conductive rails from the
first location to the second location. The method also can include
identifying changes in the transmitted current and in the received
current over time in order to both identify when the one or more of
the rail vehicles travel between the first location and the second
location and when at least one of: ballast material disposed
between the conductive rails becomes contaminated to at least
partially form a short between the conductive rails, a foreign
object other than the one or more rail vehicles forms the short
between the conductive rails, or one or more of the conductive
rails is damaged or broken between the first location and the
second location.
[0114] In one aspect, the changes in the transmitted current and
the changes in the received current indicate that the ballast
material is contaminated when the transmitted current increases and
the received current decreases over an extended period of time that
is longer than a time period during which the one or more rail
vehicles travel over the conductive rails between the first
location and the second location at a track speed of the conductive
rails.
[0115] In one aspect, the changes in the transmitted current and
the changes in the received current indicate that the foreign
object is forming the short between the conductive rails responsive
to the transmitted current increasing and the received current
concurrently decreasing, followed by one or more temporary changes
in the transmitted current and one or more temporary changes in the
received current occurring during common time periods.
[0116] In one aspect, the changes in the transmitted current and
the changes in the received current indicate that one or more of
the conductive rails is damaged or broken when the transmitted
current decreases and the received current is concurrently
eliminated.
[0117] It is to be understood that the above description is
intended to be illustrative, and not restrictive. For example, the
above-described embodiments (and/or aspects thereof) may be used in
combination with each other. In addition, many modifications may be
made to adapt a particular situation or material to the teachings
of the inventive subject matter without departing from its scope.
While the dimensions and types of materials described herein are
intended to define the parameters of the inventive subject matter,
they are by no means limiting and are exemplary embodiments. Many
other embodiments will be apparent to one of ordinary skill in the
art upon reviewing the above description. The scope of the
inventive subject matter should, therefore, be determined with
reference to the appended claims, along with the full scope of
equivalents to which such claims are entitled. In the appended
claims, the terms "including" and "in which" are used as the
plain-English equivalents of the respective terms "comprising" and
"wherein." Moreover, in the following claims, the terms "first,"
"second," and "third," etc. are used merely as labels, and are not
intended to impose numerical requirements on their objects.
Further, the limitations of the following claims are not written in
means-plus-function format and are not intended to be interpreted
based on 35 U.S.C. .sctn.112(f), unless and until such claim
limitations expressly use the phrase "means for" followed by a
statement of function void of further structure.
[0118] This written description uses examples to disclose several
embodiments of the inventive subject matter and also to enable one
of ordinary skill in the art to practice the embodiments of
inventive subject matter, including making and using any devices or
systems and performing any incorporated methods. The patentable
scope of the inventive subject matter is defined by the claims, and
may include other examples that occur to one of ordinary skill in
the art. Such other examples are intended to be within the scope of
the claims if they have structural elements that do not differ from
the literal language of the claims, or if they include equivalent
structural elements with insubstantial differences from the literal
languages of the claims.
[0119] The foregoing description of certain embodiments of the
present inventive subject matter will be better understood when
read in conjunction with the appended drawings. To the extent that
the figures illustrate diagrams of the functional blocks of various
embodiments, the functional blocks are not necessarily indicative
of the division between hardware circuitry. Thus, for example, one
or more of the functional blocks (for example, processors or
memories) may be implemented in a single piece of hardware (for
example, a general purpose signal processor, microcontroller,
random access memory, hard disk, and the like). Similarly, the
programs may be stand-alone programs, may be incorporated as
subroutines in an operating system, may be functions in an
installed software package, and the like. The various embodiments
are not limited to the arrangements and instrumentality shown in
the drawings.
[0120] As used herein, an element or step recited in the singular
and proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "one embodiment"
of the present inventive subject matter are not intended to be
interpreted as excluding the existence of additional embodiments
that also incorporate the recited features. Moreover, unless
explicitly stated to the contrary, embodiments "comprising,"
"including," or "having" an element or a plurality of elements
having a particular property may include additional such elements
not having that property.
* * * * *