U.S. patent application number 15/351306 was filed with the patent office on 2017-03-02 for rail assembly and composite polymer crossties therefor.
The applicant listed for this patent is DUROPAR HOLDING CORPORATION. Invention is credited to Brian ABRAMSON, James R. INGLIS.
Application Number | 20170058460 15/351306 |
Document ID | / |
Family ID | 54479086 |
Filed Date | 2017-03-02 |
United States Patent
Application |
20170058460 |
Kind Code |
A1 |
ABRAMSON; Brian ; et
al. |
March 2, 2017 |
RAIL ASSEMBLY AND COMPOSITE POLYMER CROSSTIES THEREFOR
Abstract
Disclosed are different embodiments of a railway tie assembly
for securing a rail along a railway track. In one embodiment, the
assembly comprises a plurality of composite polymer crossties
fabricated from a composition comprising an asphaltic component, a
polymeric composition component and a strengthening agent; and a
pair of rail clips for securing the rail across each of said
composite polymer crossties, wherein each of the rail clips
comprises a rail-engagement portion configured to engage a
corresponding railseat, and an anchoring portion to be anchored to
a given crosstie and cooperate with the rail-engagement portion to
secure the corresponding railseat against a load-bearing surface of
the given crosstie.
Inventors: |
ABRAMSON; Brian; (Brampton,
CA) ; INGLIS; James R.; (Brampton, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DUROPAR HOLDING CORPORATION |
Brampton |
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CA |
|
|
Family ID: |
54479086 |
Appl. No.: |
15/351306 |
Filed: |
November 14, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/CA2015/050392 |
May 5, 2015 |
|
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15351306 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E01B 3/46 20130101; E01B
9/02 20130101 |
International
Class: |
E01B 3/46 20060101
E01B003/46; E01B 9/02 20060101 E01B009/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 15, 2014 |
CA |
2852525 |
Claims
1. A railway tie assembly for securing a rail along a railway
track, the assembly comprising: a plurality of composite polymer
crossties fabricated from a composition comprising an asphaltic
component, a polymeric composition component and a strengthening
agent; and a pair of rail clips for securing the rail across each
of said composite polymer crossties, wherein each of said rail
clips comprises a rail-engagement portion configured to engage a
corresponding railseat, and an anchoring portion to be anchored to
a given crosstie and cooperate with said rail-engagement portion,
once installed, to secure said corresponding railseat against a
load-bearing surface of said given crosstie.
2. The assembly as defined in claim 1, wherein an anchoring of the
rail to said crossties is maintained or strengthened under use by
virtue of said composition.
3. The assembly as defined in claim 2, wherein said load-bearing
surface is defined by a correspondingly dimensioned channel formed
within said given crosstie so as to at least partially receive said
corresponding railseat therein.
4. The assembly as defined in claim 3, wherein said anchoring
portion comprises a fastener-receiving aperture formed therein to
receive cooperative engagement of a fastener therethrough such
that, upon fastening said fastener to said given crosstie through
said aperture, an anchoring pressure is applied through said
rail-engagement portion to said corresponding rail seat.
5. The assembly as defined in claim 4, wherein said fastener is a
screw-type threaded fastener.
6. The assembly as defined in claim 3, wherein said load-bearing
surface is defined by a corresponding pair of correspondingly
dimensioned channels formed within said given crosstie so as to at
least partially receive said corresponding railseat therein.
7. The assembly as defined in claim 6, wherein said channels are
outwardly inclined channels formed within said given crosstie so as
to at least partially receive inclined said corresponding railseat
therein.
8. The assembly as defined in claim 7, wherein an outward
inclination is from about 1:40 cant to about 1:10 cant.
9. The assembly as defined in claim 7, wherein an outward incline
of said at least one channel is about 1:20 cant.
10. The assembly as defined in claim 6, wherein each of said rail
clips further comprises a respective inner shim and outer shim to
be disposed so as to downwardly bias said rail-engagement portion
against said corresponding railseat as said fastener is secured to
said given crosstie.
11. The assembly as defined in claim 10, wherein said outer shim
has a greater thickness than said inner shim.
12. The assembly as defined in claim 6, further comprising
respective lateral abrasion guards to be located along an outermost
sidewall region of each of said respective channels.
13. The assembly as defined in claim 10, further comprising
respective lateral abrasion guards to be located along an outermost
sidewall region of each of said respective channels, wherein said
abrasion guards further comprise a flange portion extending from
said respective channels and to which is coupled said outer
shim.
14. The assembly as defined in claim 6, further comprising
respective base abrasion guards to be located within said
respective channels along a base thereof to have said corresponding
railseat rest thereon.
15. The assembly as defined in claim 6, further comprising
respective inner abrasion guards to be located along an innermost
sidewall region of each of said respective channels.
16. The assembly as defined in claim 1, wherein said load-bearing
surface is defined by a corresponding pair of outwardly inclined
wedges formed within said given crosstie so as to at least
partially receive inclined said corresponding railseat therein.
17. The assembly as defined in claim 1, wherein each said anchoring
portion is mounted in pairs to said given composite crosstie such
that facing structural features thereof define said load-bearing
surface therebetween while at least partially directly or
indirectly limiting a lateral travel of said rail once received
thereon.
18. The assembly as defined in claim 17, further comprising a
respective collar to be fitted about said facing structural
features to further limit said lateral travel.
19. The assembly as defined in claim 17, wherein said
rail-engagement portion is slidingly engaged in a pre-assembled
configuration with said anchoring portion to slide laterally
against said corresponding railseat into a rail-engagement
configuration.
20. The assembly as defined in claim 1, wherein said composition
comprises from about 15% to about 95% by weight of said asphaltic
component, from about 5% to about 85% by weight of said polymeric
composition component wherein said polymeric composition component
includes said strengthen agent.
21. The assembly as defined in claim 1, wherein said composition
comprises a first portion comprising from about 15% to about 75% by
weight of a first asphaltic component and from about 25% to about
85% by weight of a first polymeric composition component and a
second portion comprising from about 20% to about 85% by weight of
a second asphaltic component and from about 15% to about 85% by
weight of a second polymeric composition component; wherein each of
said first portion and said second portion includes said
strengthening agent and wherein during manufacturing of said
composite polymer crosstie said first portion and said second
portion are suitably heated and co-extruded wherein one of said
first portion or said second portion forms a core portion of said
composite polymer crosstie and the other forms an outer portion of
said composite polymer crosstie.
22. The assembly as defined in of claim 20, wherein said
strengthening agent includes fibres or reinforcing agents.
23. The assembly as defined in claim 21, wherein said strengthening
agent includes fibres or reinforcing agents
24. The assembly as defined in claim 22, wherein said fibres are
glass fibres.
25. The assembly as defined in claim 23, wherein said fibres are
glass fibres.
26. The assembly as defined in claim 1, wherein said asphalt
component comprises asphalt particles such that at least 75% of the
asphalt particles can pass through a 0.75'' mesh screen.
27. The assembly as defined in claim 1, wherein said asphalt
component comprises asphalt particles such that at least 50% of the
asphalt particles can pass through a 0.5'' mesh screen.
28. The system as defined in claim 1, wherein said composition is
adapted to allow said railseat to rest directly on said
load-bearing surface without adversely increasing wear of said
crossties under use.
29. The system as defined in claim 1, wherein said composition is
adapted to allow said railseat to rest directly or indirectly on
said load-bearing surface absent a surface area-increasing
force-distributing plate without adversely increasing wear of said
crossties under use.
30. A railway track comprising: a plurality of composite polymer
crossties fabricated from a composition comprising an asphaltic
component, a polymeric composition component and a strengthening
agent, wherein said crossties are disposed at regular intervals
along the railway track; one or more rails each composed of rail
segments juxtaposed end-to-end along the railway track, a
respective railseat thereof disposed crosswise upon a respective
load-bearing surface of each of said crossties; and respective
pairs of rail clips securing respective ones of said rail segments
to each of said composite polymer crossties, wherein each of said
rail clips comprises a rail-engagement portion engaging a
corresponding railseat, and an anchoring portion anchored to a
given composite crosstie and cooperating with said rail-engagement
portion to secure said corresponding railseat against said
respective load-bearing surface of said given crosstie.
31. The railway track according to claim 30, wherein an anchoring
of said rail segments to said crossties strengthens under use by
virtue of said composition.
32. The railway track according to claim 30, wherein said rail
segments are disposed directly upon said load-bearing surface in
absence of a corresponding tie plate, wherein said composition
allows said absence without adversely increasing wear of said
crossties under use.
33. The railway track according to claim 30, wherein said rail
segments are disposed upon said load-bearing surface via respective
abrasion guards, only, in absence of a corresponding tie plate,
wherein said composition allows for said absence without adversely
increasing wear of said crossties under use.
Description
RELATED APPLICATION
[0001] The present application is a U.S. Continuation application
which claims benefit of priority to International Patent
Application serial number PCT/CA2015/050392 entitled "Rail Assembly
and Composite Polymer Crossties Therefor", filed May 5, 2015 which
in turn which claims benefit of priority to Canadian Patent
Application serial number 2,852,525 entitled "Rail Assembly and
Composite Polymer Crossties Therefor", filed May 15, 2014, the
subject matter of which are herein incorporated by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to rail assemblies, and in
particular, to a rail assembly and composite polymer crossties
therefor.
BACKGROUND
[0003] Conventional wooden timber crossties and concrete railway
crossties coupling systems require that the railway rails be
coupled to the crosstie such that the two railway rails maintain a
specific spacing corresponding to the wheel spacing of wheels
coupled to an axle of a railway car. A rail is typically coupled to
the crosstie by way of two or more rail clips which are coupled to
the crosstie by way of an intervening tie plate fastened to the
crosstie using spikes or screw-type spikes. A portion of the clip
correspondingly applies pressure to the railseat to maintain the
rail against the crosstie.
[0004] The compressive forces exerted by a train as it passes over
a given railway crosstie are known to cause degradation in the
railway crosstie. For example, in the case of wooden crossties, the
compressive force of the base (railseat) of the railway rail, with
the tie plate thereunder, against the crosstie as a train passes
thereover, over time causes the wood fibres of the crosstie to
breakdown. Therefore the railway rail, or the tie plate in
instances where one is present, cuts into the wood and a gap is
formed between the bottom of the railway rail and the crosstie.
Similarly in the case of concrete crossties, the compressive forces
cause the concrete and/or a compression pad ("also termed a cushion
mat") under the tie plate to wear under the railway rail and a gap
to form. Repeated train travel along the rails causes the rail to
flex into the created gap and impact the crosstie, thus causing
further breakdown of the crosstie and the gap to increase in size.
With concrete crossties, the impact of the rail across the gaps may
cause the concrete crosstie to fracture, leading to catastrophic
failure.
[0005] Also, as the gap increases, the constant flexing and
retraction of the rail as a train travels thereover is known to
cause the fasteners coupling the rail or tie plate to the crosstie
to loosen. This creates a situation where the gap is further
increased and/or the rail becomes uncoupled from the crosstie. In
such cases where uncoupling occurs, if the crosstie has not
suffered a failure where it needs to be replaced, the crosstie will
need to be "re-spiked" which is time-consuming and costly. During
re-spiking, the original spike hole must be plugged and a new spike
bore made. The rail can then again be coupled to the crosstie.
[0006] In order to reduce the incidence of catastrophic failure, in
both the case of wooden crossties and concrete crossties,
maintenance crews must be deployed to survey railway lines for
developing gaps between railway rails and corresponding crossties.
Once a gap is detected the maintenance crew must undertake to
tighten the fasteners and secure the rail against the crosstie.
However, by such a time, significant damage may have already been
done to the crosstie. For example, in the case of a wooden
crosstie, once a gap of from about 3/8'' to about 1/2'' is
developed, the rail must be tightened.
[0007] In order to mitigate a gap developing, the industry has
accepted the use of surface area-increasing force-distributing
plates and/or cushion mats being placed between the bottom of the
rail and the crosstie. For example, resilient cushioning mats, or
cushion mats are used in conjunction with concrete crossties to
minimize abrasion of the railseat area, and reduce impact and
vibration effects on the track structure in an attempt to minimize
gaps from forming. In the case of wooden crossties, a surface
area-increasing force-distributing steel plate is often used
between the railseat and the crosstie to increase the surface area
and distribute the compressive forces from the train over a larger
area of the crosstie. This aids to reduce the wood fibres
immediately under the rail from breaking down as rapidly as if the
surface area-increasing force-distributing steel plate were not
present. However, it is known that with both of these approaches,
the crossties still breakdown by way of the compressive forces,
and/or abrasion, and the fasteners retract from their respective
seats resulting in a gap between the bottom of the rail and the
crossties still forming. Therefore, the use of cushion mats and
surface area-increasing force-distributing steel plates serve to
increase the life a crosstie, yet significant maintenance to
tighten the rails to the crossties is still required. Furthermore,
the required use of the cushion mats and surface area-increasing
force-distributing steel plates increases the unit cost of each
crosstie installation.
[0008] United States Patent Application Publication number US
2006/0226247 A1, published Oct. 12, 2006 to Abramson, et al. and
entitled "Railway Ties and Structural Elements" describes a
composite structural element such as a railway tie made from an
asphaltic component and a fibre reinforced plastics component.
[0009] U.S. Pat. No. 8,252,216, issued Aug. 28, 2012 to Abramson,
et al. and entitled "Method for the Production of Railway Ties"
describes a method for producing composite railway ties from two
co-extruded compositions where each composition comprises an
asphaltic component, a polymeric component and a strengthening
agent. The strengthening agent may be a fibre and is preferably a
glass fibre.
[0010] This background information is provided to reveal
information believed by the applicant to be of possible relevance.
No admission is necessarily intended, nor should be construed, that
any of the preceding information constitutes prior art.
SUMMARY
[0011] The following presents a simplified summary of the general
inventive concept(s) described herein to provide a basic
understanding of some aspects of the invention. This summary is not
an extensive overview of the invention. It is not intended to
restrict key or critical elements of the invention or to delineate
the scope of the invention beyond that which is explicitly or
implicitly described by the following description and claims.
[0012] There is a need in the industry to provide a system
including a crosstie which is more resistant to compressive forces
exerted by a passing train and one which improves fastener
retention. Also, it would be advantageous to provide a system which
can meet the abovementioned needs, as well as other needs, with
fewer parts, lower overall material costs, installation costs
and/or lifetime maintenance costs. Lower lifetime maintenance cost
may, for example, be realized by less required maintenance over the
lifetime of a given crosstie installation.
[0013] It has been surprisingly discovered that using a system such
as that described herein which makes use of composite polymer
crossties improves the coupling of railway rails to crossties over
the conventionally used wood or concrete crosstie systems. For
example, in various testing models employed it was shown that using
the system disclosed herein, rail/plate area compression testing of
the crossties returned values far exceeding industry requirements,
and embedded screw-spike/threaded insert pull-out testing also
returned values far exceeding the industry requirements and that
which is conventionally expected for wooden, concrete and other
composite crossties.
[0014] In accordance with one aspect, there is provided a railway
tie assembly for securing a rail along a railway track, the
assembly comprising: a plurality of composite polymer crossties
fabricated from a composition comprising an asphaltic component, a
polymeric composition component and a strengthening agent; and a
pair of rail clips for securing the rail across each of said
composite polymer crossties, wherein each of said rail clips
comprises a rail-engagement portion configured to engage a
corresponding railseat, and an anchoring portion to be anchored
within a given crosstie and cooperate with said rail-engagement
portion, once installed, to secure said corresponding railseat
against a load-bearing surface of said given crosstie.
[0015] In accordance with one such aspect, an anchoring of the rail
to said crossties maintains or strengthens the anchoring portion's
gripping power to the crosstie under use by virtue of said
composition.
[0016] In accordance with another aspect, there is provided a
railway track comprising: a plurality of composite polymer
crossties fabricated from a composition comprising an asphaltic
component, a polymeric composition component and a strengthening
agent, wherein said crossties are disposed at regular intervals
along the railway track; one or more rails each composed of rail
segments juxtaposed end-to-end along the railway track, a
respective railseat thereof disposed crosswise upon a respective
load-bearing surface of each of said crossties; and respective
pairs of rail clips securing respective ones of said rail segments
to each of said composite polymer crossties, wherein each of said
rail clips comprises a rail-engagement portion engaging a
corresponding railseat, and an anchoring portion anchored to a
given composite crosstie and cooperating with said rail-engagement
portion to secure said corresponding railseat against said
respective load-bearing surface of said given crosstie.
[0017] In accordance with one such aspect, an anchoring of said
rail segments to said crossties is maintained or strengthened under
use by virtue of said composition.
[0018] Other aims, objects, advantages and features of the
invention will become more apparent upon reading of the following
non-restrictive description of specific embodiments thereof, given
by way of example only with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE FIGURES
[0019] In order that the invention may be better understood,
exemplary embodiments will now be described by way of example only,
with references to the accompanying drawings, wherein:
[0020] FIG. 1a is a top perspective view of a portion of an
exemplary composite polymer crosstie having a railseat receiving
rectangular channel formed therein, in accordance with one
embodiment;
[0021] FIG. 1b is a top perspective view of a portion of a
composite polymer crosstie having an exemplary railseat and
abrasion guard receiving rectangular channel formed therein, as
shown in ghost lines, in accordance with one embodiment;
[0022] FIG. 1c is a front elevation view of the composite polymer
crosstie portion of FIG. 1a showing a cross-sectional view of a
rail section mounted thereon with a railseat thereof received in
the rectangular channel;
[0023] FIG. 2a is a top plan view of the composite polymer crosstie
portion of FIG. 1a showing a rail portion coupled thereto using
exemplary inner and outer rail clips and with a portion of the
railseat received in the rectangular channel, in accordance with
one embodiment;
[0024] FIG. 2b is a top plan view of the composite polymer crosstie
section of FIG. 1b showing a rail portion coupled thereto using
exemplary inner and outer rail clips and with a portion of the
railseat and an exemplary abrasion guard received in the
rectangular channel;
[0025] FIG. 3a is a top plan view of a portion of railway tracks
showing a plurality of the composite polymer crossties of FIG. 1a
with two rail sections coupled thereto using exemplary inner and
outer rail clips and with portions of the respective railseats
received in respective rectangular channels;
[0026] FIG. 3b is an enlarged top perspective view of a portion of
the rail installation of FIG. 3a showing inner and outer shims in
communication with respective inner and outer rail clips and
further showing in cross section the railseat received in the
rectangular channel, in accordance with one embodiment;
[0027] FIG. 4 is a side view of an alternative rail installation
similar to that shown in FIG. 3b showing inner and outer rail clips
coupled to the composite polymer crosstie using fasteners bored
into the composite polymer crosstie (shown in ghost lines), and
further showing an abrasion guard received along an outermost
sidewall of the rectangular channel;
[0028] FIG. 5 is a side view of an alternative rail installation
similar to that shown in FIG. 4, comprising an extended abrasion
guard having a flange portion extending along a top surface of the
composite polymer crosstie and along a bottom load-bearing surface
of the rectangular channel;
[0029] FIG. 6 is a side view of an alternative rail installation
similar to that shown in FIG. 5, comprising a further extended
abrasion guard having an inner rectangular channel sidewall
portion;
[0030] FIG. 7 is a top perspective view of a partially assembled
rail assembly composed of an exemplary composite polymer crosstie
having a railseat-receiving wedge formed therein and opposed rail
clip anchoring structures fastened on either side thereof to
directly or indirectly restrict a lateral travel of a railseat
subsequently disposed therebetween;
[0031] FIG. 8 is a top perspective view of the assembly of FIG. 7,
further showing respective rail-engaging portions slidingly
received within corresponding anchoring portions of the anchoring
structures in a pre-assembled configuration, a rail received
inclined in the railseat-receiving wedge, and respective collars
disposed about the anchoring portions to directly restrict a
lateral travel of the railseat resting therebetween; and
[0032] FIG. 9 is an enlarged perspective view of the assembly of
FIG. 8 once fully assembled, showing a sliding engagement of the
rail-engaging portion upon the railseat.
DETAILED DESCRIPTION
[0033] With reference to the disclosure herein and the appended
figures, a rail assembly and composite polymer crossties therefor
will now be described in accordance with various embodiments of the
invention.
[0034] With reference to FIGS. 1a, 1b and 1c, and in accordance
with one embodiment, an exemplary composite polymer crosstie 12 is
shown for use in a rail assembly as contemplated herein and
described below (e.g. see assembly 10 of FIG. 2a). In this
embodiment, the composite polymer crosstie 12 has a rectangular
channel 14 formed or cut in a top surface 16 thereof for receiving
therein a base portion or railseat 18 of a railway rail 20 as shown
in FIG. 1c. In some embodiments the rectangular channel 14 is
dimensioned across distance A to substantially match the width of
the railseat 18. However, in other embodiments shown for example in
FIGS. 4 to 6, the rectangular channel 14 may be dimensioned across
A to also fit an abrasion guard 22 along with the railseat 18. In
these embodiments, the rectangular channel is further dimensioned
to have a depth B suitable to accommodate the railseat 18, and
optionally different embodiments of the abrasion guard 22 as shown
in FIGS. 4 to 6. An exemplary depth B for use with the various
embodiments of abrasion guards 22 is also shown in ghost in FIG. 1b
relative to the rectangular channel 14 for use in embodiments
devoid of an abrasion guard 22. Accordingly, the rectangular
channel 14 serves to inhibit or prevent lateral movement of the
railway rail 20 relative to the crosstie 12 during use.
[0035] Turning now to the rectangular channel 14, a bottom
load-bearing surface 24 of the rectangular channel 14, in some
embodiments, is provided such that it is parallel with the
composite polymer crosstie 12 top surface 16. However, in some
embodiments the railhead 26 may be inwardly inclined or canted
(i.e. toward one another in a two rail assembly) as shown, for
example, in FIGS. 1c, and 4 to 6 at angle .theta.. Accordingly, the
bottom surface 24 may be provided at an angle which is inclined
towards an outer edge 28 of the composite polymer crosstie 12. The
cant angle .theta. to the rail 20, and thus the railhead 26
resultant from the outward incline of the bottom surface 24, is
shown in the figures relative to vertical at .theta.. The cant to
the railhead 26 may be, for example, from about 1:40 to about 1:10
dependent on that required by the specific application of the rail
assembly and composite polymer crossties 12 used therefor. In some
examples, the cant is provided at about 1:20. The cants noted
herein should not be considered to be limiting and are provided for
exemplary purposes, only. One of skill in the art would readily
understand which cants may be required for specific applications.
In other embodiments the bottom surface 24 may be provided as being
parallel with the top surface 16 and the abrasion guard 22, in
embodiments with an abrasion guard bottom portion 22a, as shown in
FIGS. 5 and 6, for example, may be fashioned to provide the desired
cant to the railhead 26. Therefore, in such embodiments the
abrasion guard base portion 22a may be wedge-shaped to provide the
outward incline as noted above.
[0036] With reference now to FIGS. 3a and 3b, and in accordance
with one embodiment, a plurality of composite polymer crossties 12
are provided to have coupled thereto and maintain two rails 20 at a
desired spacing. FIG. 3b shows an enlarged perspective view of the
assembly 10 in relation to a cut through section of one of the
rails 20. The railseat 18 is laid into a correspondingly
dimensioned rectangular channel 14 such that the railseat 18 fits
substantially snuggly in the rectangular channel 14. An inner rail
clip 30 and an outer rail clip 32 are provided to maintain the
railseat 18 in the rectangular channel 14 and thus couple the rail
20 to the composite polymer crosstie 12.
[0037] Both the inner rail clip 30 and the outer rail clip 32 are
provided in the embodiments described herein as having a
substantially "W" shape, as can be seen in the figures.
Furthermore, as can be seen in FIGS. 3b to 6, for example, the
inner rail clip 30 and the outer rail clip 32 have an arced profile
which aids to provide resiliency against vibrations from a train
passing along the rails and to maintain the rail 20 in a coupled
arrangement with the composite polymer crossties 12. Such
resiliency provided by a formed arc of the inner and outer rail
clips 30 and 32 allows a degree of bending of the rail clips under
load and resists fracturing of the rail clips with repeated
vibrations and train travel. Should the inner rail clip 30 and the
outer rail clip 32 not be provided with some degree of resiliency,
they may have a tendency to prematurely crack and fail.
[0038] The inner rail clip 30 has a shim contacting outer portion
30a, a rail contacting inner portion 30b (e.g. rail-engagement
portion) and a center region (e.g. anchoring structure) having a
fastener passage 30c, as shown, for example in FIG. 2a. Similarly,
the outer rail clip 32, also as shown in FIG. 2a, has a shim
contacting outer portion 32a, a rail contacting inner portion 32b
and a center portion having a fastener passage 32c.
[0039] As shown in the figures, a fastener 34 is passed through the
fastener passages 30c and 32c located in the center portion of the
respective rail clips 30 and 32. The faster 34 is inserted and
maintained in a bore 36 of the composite polymer crosstie 12 as
shown, for example, in FIGS. 4 to 6. In some embodiments, such as
the ones provided in the figures, the fastener 34 may be provided
as a screwspike fastener having helical threads as is commercially
available and known in the art. In other embodiments (not shown),
the fastener 34 may be provided as an impact force-driven spike
which is devoid of helical threads. The general shape of the inner
and outer rail clips 30 and 32 should not be limited specifically
to a "W" shape as other rail clips, such as that described below
with reference to FIGS. 7 to 9 in accordance with another
illustrative embodiment, may be readily considered herein without
departing from the general scope and nature of the present
disclosure. The "W" shape is noted herein as an example, only,
other shapes for the inner and outer rail clips 30 and 32 may be
suitable. For example, such a shape for one or both of the inner
and outer rail clips 30 and 32 may be a "V" shape, a "U" shape, a
"J" shape, an "N" shape, and so on.
[0040] With reference to FIG. 3b, the assembly 10 also includes
shims 38 and 40, which, in use, are respectively placed on the top
surface 16 of the composite polymer crossties 12 under the shim
contacting outer portions 30a and 32a of the inner rail clip 30 and
the outer rail clip 32 respectively. The fasteners are then
inserted and driven into the composite polymer crossties 12 as
shown in the figures, passing through the respective inner and
outer rail clip fastener passages 30c and 32c. Therefore, in use,
the rail contacting inner portions 30b and 32b of the respective
inner and outer rail clips 30 and 32, with the fasteners 34 in
place maintain, the railseat 18 in the rectangular channel 14. The
inner shim 38 and the outer shim 40 are provided to elevate the
shim contacting outer portions 30a and 32a and thus increase the
toe pressure of the rail contacting inner portions 30b and 32b on
the respective areas of the railseat 18, as shown in particular in
FIGS. 3b to 6. Additionally, as shown in the aforementioned
figures, in some embodiments, it is preferable to have the outer
shim 40 be of a greater height or thickness as compared to the
inner shim 38 so as to increase the toe pressure applied to the
railseat 18 along the outer side thereof (i.e. in a two rail
system). Such increased toe pressure of the outer rail clip 32
compared to the inner rail clip 30 may be used, for example, in
applications where the railhead 26 is inwardly inclined as shown in
FIGS. 4 to 6 by way of an outwardly inclined rectangular channel
bottom surface 24, as discussed above. The increased toe pressure
provided by the outer shim 40 having an increased thickness versus
the inner shim 38, may also aid to maintain the railseat 18 in the
rectangular channel 14 and counter the downward forces applied to
the railhead 26 by a train passing thereover. In embodiments where
the railhead 26 is inwardly inclined, as shown in FIGS. 4 to 6, for
example, should sufficient toe pressure not be applied at the rail
contacting inner portion 32b of the outer rail clip 32, the rail 20
may have a tendency to rotate inward and lead to failure of the
system. In some embodiments, the toe pressure of the rail
contacting inner portions 30b and 32b on the respective areas of
the railseat 18 is provided in a range from about 500 psi to about
10,000 psi by way of tightening corresponding fastener 34 and the
interaction of the shim contacting outer portions 30a and 32a with
shims 38 and 40, respectively. Additionally, for example, the
dimensions of shims 38 and 40 may also be varied in order to
achieve the desired toe pressures. In preferred embodiments the toe
pressure of the rail contacting inner portions 30b and 32b is
provided in a range from about 2,000 psi to about 3,200 psi.
Various different toe pressures may be required depending on the
application of the assembly defined herein so as to couple the
railway rail 20 to the crosstie 12 in different environments and
may be readily determined by one of skill in the art.
[0041] As discussed below in more detail with respect to the
testing of the composite polymer crossties 12 of the instant
disclosure, although the composite polymer crossties 12 of the
system 10 as disclosed herein are more resistant to abrasion and
compressive forces compared to conventionally used wooden
crossties, in some instance it may be desirable for the system 10
to include an abrasion guard 22. Various embodiments and
orientations of the abrasion guard 22 are discussed above in
relation to their installation relative the railseat 18 and the
rectangular channel 14. More specifically, the abrasion guard 22 in
one embodiment, as shown FIG. 4, may be placed in the rectangular
channel 14 along an outermost side wall 42 of the rectangular
channel 14. In such an embodiment, the rectangular channel 14 along
distance A is made wider so as to accommodate the width of the
railseat 18 plus the abrasion guard 22. For example, with an
abrasion guard 22 fashioned and employed as shown in FIG. 4, the
forces exerted on the rail 20 by a train passing thereover and
applied both downward and in the direction towards the outer edge
28 of the composite polymer crosstie 12 are absorbed by the
abrasion guard 22 so as to reduce damage/wear to the composite
polymer crosstie 12 along the outermost side wall 42 of the
rectangular channel 14. Additionally, such an abrasion guard 22 may
also aid to afford protection against cracking or fracturing to the
composite polymer crosstie 12 starting at the intersection of the
outermost side wall 42 and the rectangular channel bottom wall 24
as well as damage to the outermost side wall 42 itself owing to
forces resultant from trains repeatedly passing along rail 20.
[0042] FIG. 5 shows another embodiment of the abrasion guard 22
wherein an abrasion guard base portion or flange 22a is provided.
In such an embodiment the abrasion guard 22 is fashioned to line
the outermost sidewall 42 as well as the bottom wall 24 of the
rectangular channel 14. The railseat 18 then rests on the abrasion
guard base portion 22a, in use. As shown in FIG. 6 with respect to
another embodiment of the abrasion guard 22, an innermost sidewall
46 of the rectangular channel 14 is also lined with a portion of
the abrasion guard 22, namely an inner rectangular channel sidewall
abrasion guard portion 44. Therefore, in the embodiment shown in
FIG. 6, the abrasion guard 22 is fashioned to form a substantially
"U-shaped" member in profile, which lines the interior surfaces of
the rectangular channel 14.
[0043] In other embodiments (not shown), two independent abrasion
guards may rather be provided where one of the abrasion guards is
located along the outermost sidewall 42 of the rectangular channel
14 as shown in FIG. 5 and the other of said abrasion guards 22 is
located along the innermost sidewall 46 of the rectangular channel.
In such an embodiment, the abrasion guards may be considered to be
respectively an outer rectangular channel sidewall abrasion guard
and an inner rectangular channel sidewall abrasion guard.
[0044] Although abrasion guards 22 such those shown in the
embodiments of FIGS. 4 to 6 may be optionally used in various
embodiments of the system 10 as described herein, the abrasion
guards 22 do not substantially increase the surface area from which
forces from a train passing over the rails 20 are exerted on the
composite polymer crossties 12; in other words, these rail guards
do not substantively increase a load-bearing area of the crossties,
as would otherwise be provided by conventional tie plates used in
wooden rail assemblies. Therefore, the assembly 10 generally
consists of a plateless system, that is one absent a
force-distributing plate. Unlike force-distributing plates which
are used with conventional wooden crossties and variations thereof
in the case of conventional concrete crossties, the optional
abrasion guards noted herein are provided for the purposes of
inhibiting abrasion damage and fracturing of the composite polymer
crossties 12 at certain points of the railseat 18 maintaining
rectangular channel 14. The various embodiments of abrasion guards
22 disclosed herein do not act to substantially increase the
surface area of the railseat 18 to distribute compressive forces
over a larger area of the crosstie.
[0045] Additionally, in some embodiments, such as the ones shown
for example in FIGS. 5 and 6, the abrasion guard 22 may be
fashioned to have a flange portion 48 which extends along a portion
of the top surface 16 of the composite polymer crosstie 12 towards
the composite polymer crossties outer edge 28. In some embodiments,
the outer shim 40 may be coupled to the flange portion 48, whereas
in other embodiments, the outer shim 40 may be integrally formed
with the flange portion 48. The flange portion 48, in the various
abovementioned embodiments, may have a passage made therein (not
shown) for receiving therethrough a portion of the fastener 34
employed with outer rail clip 32. By having the flange 48 receive
therethrough a portion of the fastener 34, the abrasion guard 22 is
resistant to movement and as such is not able to move out of place
in the rectangular channel 14. Vibrations caused by repeated train
travel over the rails 20 may cause unsecured abrasion guards 22 to
move from the desired position and thus in certain applications it
may be desirable to protect against abrasion guard 22 movement.
[0046] With reference to FIGS. 7 to 9, an alternative rail assembly
100 will now be described in accordance with another embodiment. In
this embodiment, the rail assembly 100 again makes use of composite
polymer crossties 112 upon and across which one or more rails 126
are mounted and secured via respective rail clips 130, 132. Rather
than to provide a rectangular rail receiving channel, as shown
above with reference to FIGS. 1 to 6, a wedge-shaped cutout 114 is
fashioned in a top surface 116 of the crosstie 112 so to receive
inclined a correspondingly shaped railseat 118 therein. To secure
against lateral travel of the railseat 118 once in position, the
rail clips 130, 132, in accordance with one example, are
preassembled with the crossties 112 via respective screw-type
fasteners 135 to substantially define thereon the rail load bearing
surface therebetween. For instance, respective clip anchoring
structures 134 may be anchored to the crosstie via respective
anchoring fasteners (e.g. screw type threaded fasteners or the
like) so to define the rail load bearing surface therebetween, for
instance between respective shoulders 136 thereof. In this example,
a collar 138 is further disposed about respective anchoring
structures 134 so to further define the rail load bearing surface,
namely in providing for a direct lateral contact with the rail once
so disposed therebetween. Accordingly, the collar 138 may act to
provide a similar function as that provided by the inner and outer
channel sidewall abrasion guard portions described above with
reference to the embodiments of FIGS. 4 to 6. Otherwise, the
anchoring structure shoulders 136 may be disposed to abut directly
or substantially directly against the railseat 118 to directly
limit a lateral travel thereof once installed therebetween.
[0047] In either configuration, a rail-engagement portion 140 may
be slidingly engaged (in this embodiment) with the anchoring
portion 134 in a pre-assembled configuration and ready for
deployment upon rail installation (i.e. see FIG. 8).
[0048] With particular reference to FIG. 9, once the crossties 112
have been laid and the rails 126 disposed thereon between
respective clips 130, 132, the rail engagement portions 138 and 140
may be laterally slid into position such that a rail-engaging toe
142 (and toe cap) thereof operatively slides onto the railseat 118
to secure it into position upon the crosstie rail load-bearing
surface defined between the clips 130, 132.
[0049] The person of ordinary skill in the art will appreciate that
different rail clips may be used in the present context without
departing from the general scope and nature of the present
disclosure, namely so as to couple the railseat to a crosstie in
the appropriate position between the rail clips.
[0050] Having now generally described the rail assembly in
accordance with different illustrative embodiments, the composite
polymer crossties used therefor may be fabricated, in some
embodiments, according the compositions and methods disclosed in
United States Patent Application Publication number US 2006/0226247
A1, published Oct. 12, 2006 to Abramson, et al. and entitled
"Railway Ties and Structural Elements" and U.S. Pat. No. 8,252,216,
issued Aug. 28, 2012 to Abramson, et al. and entitled "Method for
the Production of Railway Ties"; the entire contents of each one of
which are hereby incorporated herein by reference. Other
compositions and methods wherein a composite polymer crosstie
beyond those disclosed in the abovementioned documents may also be
suitable and accordingly the instant disclosure should not be
limited thereto. Accordingly, the composite polymer crosstie may be
fabricated, in some embodiments, from a composition comprising at
least an asphaltic component, a polymeric composition component and
a strengthening agent. Furthermore, in some embodiments, the
strengthening agent may be fibres which are pre-included in the
input polymeric component. Additionally, the fibres may be
included, in some embodiments, in the starting mix pre-included in
the polymeric component. The fibres may, in some embodiments, be
glass fibres.
Exemplary Crosstie Compositions and Fabrication Methods
[0051] By way of example only, the composite polymer crossties
comprise an asphalt component, a polymeric composition component
and a strengthening agent component pre-included in the polymeric
component (thus forming a fiber-reinforced plastics component) and
optionally plastics chosen from the group consisting of virgin
plastics, recycled plastics, and combinations and mixtures thereof.
Also, as noted above, in some embodiments, the composite polymeric
crossties comprise an asphalt component, a polymeric composition
component and a strengthening agent component which is not
pre-included in the polymeric component. In some embodiments, the
asphalt component comprises between 15% and 95%, by weight of the
composite polymer crossties and the total polymeric component
content comprises between 5 and 85% by weight of the crosstie. It
should be noted that although a minor amount of impurities may be
present in the starting materials, such as moisture, the effect on
the manufacturing process of the composite structural element is
negligible.
[0052] In preferred embodiments, the asphalt component comprises
about 65% to 85% by weight of the total weight of a given composite
polymer crosstie. More preferably, the asphalt component, in some
embodiments comprises about 70% to 80% by weight of the total
weight of the composite polymer crosstie. Preferably, the total
polymeric component comprises about 10% to 45% by weight of the
total weight of the composite polymer crosstie. More preferably, in
some embodiments, the total polymeric component comprises about 15%
to 40% by weight of the total weight of the composite polymer
crossties. Even more preferably, the total polymeric component
comprises about 20% to 30% by weight of the total weight of the
composite polymer crossties.
[0053] The fiber-reinforced plastics component, in some embodiments
comprises between about 25% and 75% by weight of the total
polymeric component content. In some embodiments, the
fiber-reinforced plastics preferably comprises between about 30%
and 70% by weight of the total polymeric component content.
However, in most preferred embodiments, the fiber-reinforced
plastics component comprises between about 40% and 60% by weight of
the total plastics component content. In some embodiments, the
composite polymer crossties are formed from about 75% of an asphalt
component, about 11% of a glass fiber-reinforced polypropylene
component and about 14% of a high-density polyethylene
component.
[0054] While the composite polymer crossties are typically formed
from an asphalt component, fiber-reinforced plastics and other
plastics, the composite polymer crossties of the instant disclosure
may further comprise an elastomer in a proportion of about 0 to 80%
by weight. Preferably, the elastomer comprises between 0 and 30% by
weight of the composite polymer crosstie.
[0055] Typically, asphalt used in the composite polymer crosstie of
the instant disclosure is recycled asphalt that has been crushed
and subsequently screened for size. For example, the asphalt
component is typically passed through a series of screens having
progressively smaller square openings. Larger asphalt particles are
caught in the first screens while finer particles are caught by
later screens. In some embodiments, for example, greater than about
75% of the asphalt is able to pass through a screen having 0.75
inch square openings. However, in preferred embodiments, at least
50% of the asphalt is able to pass through a screen having 0.5-inch
square openings. For example, suitable fines of asphalt material
for use have a size from 3/4'' to about 1/4'', which are readily
available from asphalt manufacturers.
[0056] Polymeric materials suitable for use in composite polymer
crossties of the instantly disclosed system may be chosen from, for
example, low-density polyethylene (LDPE), high-density polyethylene
(HDPE), and polypropylene (PP). Additionally, although virgin
polymeric materials or, in other words, virgin plastics materials,
may be used to form the composite polymer crossties, in some
embodiments it may be preferable to use recycled plastics materials
so as to reduce the amount of waste in our environment. Such
recycled plastics materials may be polymeric materials such as, for
example, polyvinyl chloride (PVC), low-density polyethylene (LDPE),
high-density polyethylene (HDPE), polypropylene (PP), polystyrene
(PS), polyethylene terephthalate (PET), and combinations and
mixtures thereof.
[0057] The polymeric material component, in some embodiments, is
prepared for incorporation into the composite polymer crosstie
during the manufacturing process of the composite polymer
crossties, by aligning the mesh sizing with that noted above for
the asphalt component or smaller. The polymeric component may also
be sized as required by pelletizing, grinding or flaking or
otherwise provided at a suitable particle size.
[0058] The polymeric component, when provided as a fibre-reinforced
plastics component, may be, for example glass-filled polypropylene
with a pre-determined proportion of glass fibres. Such a material
is readily available commercially and as a recycled material where
the glass is intertwined with the polypropylene and is continuous
throughout the polypropylene component. Embodiments utilizing
glass-filled polypropylene are preferred as the inclusion of the
glass fibres enhances the strength of the composite polymer
crosstie. Other fibers (such as carbon fibers or silicon fibers)
may also be utilized in various embodiments to reinforce the
polymeric component and thus the composite polymeric crossties.
[0059] In addition to the asphalt component, the fiber-reinforced
polymeric components and other plastics materials, the composite
polymer crossties in some embodiments may further comprise an
elastomer. The elastomer is preferably tire rubber that has been
recycled from sources such as scrap tires. In such embodiments, at
least about 75% of the elastomer is able to pass through a screen
mesh having 0.25-inch square openings. However in preferred
embodiments, at least about 75% of the elastomer is able to pass
through a screen mesh having 0.125-inch square openings.
[0060] Furthermore, in some embodiments, the composite polymer
crossties may be made from more than one composition. For example,
a first portion and a second portion. The first portion and the
second portion comprise the asphalt component, the polymer
component and the strengthening agent as described above. However,
the first portion may comprise from about 15% to 75% asphaltic
component and from about 85% to 25% of a first polymeric component,
and optionally a strengthening agent. in some embodiments, the
first polymeric component comprises about 50% of a plastics
material and about 50% of a glass fibre-filled recyclable
thermoplastic material, such as a glass fibre-filled polypropylene,
acting as the strengthening agent. In such embodiments, the second
portion may comprise from about 20% to about 85% by weight of an
asphaltic component and from about 15% to about 80% by weight of a
second polymeric component, and optionally a strengthening agent.
In some embodiments, the second polymeric component comprises a
glass fibre-filled recyclable thermoplastic material as a
strengthening agent
[0061] Briefly, composite polymer crossties may be manufactured
utilizing the first and second portions noted above according to
the method as disclosed in U.S. Pat. No. 8,252,216. For example,
the first and second portions may be separately prepared and
blended. The first and second portions are then separately heated
to a temperature suitable to at least melt a portion the polymeric
component and then processed in processors operable to heat and
feed said blends separately as composite asphalt plastic
compositions to pump means associated with a co-extrusion die. The
heated and pliable first portion is then pumped into a first
section of a mold to form a core portion of the composite polymer
crosstie, and the heated and pliable second portion is
simultaneously pumped into an outer portion of the mold to form the
outer portion of the composite polymer crosstie. However, in some
embodiments, it may be preferable to reverse the order such that
the second portion is used to form the core and the first portion
is used to form the outer portion.
TESTING EXAMPLES
[0062] Composite polymer crossties produced from compositions as
noted above were tested to determine if composite polymer crossties
for use in the instantly disclosed system met the specifications
laid out in Section 5.3.3., Chapter 30, Part 5 of AREMA (American
Railway Engineering and Maintenance-of-Way Association) manual
(2012) regarding Engineered Composite Ties. Briefly, a composite
polymer crosstie suitable for use in railway systems must meet the
mechanical and performance requirements set forth in Table 30-5-1
of the abovementioned section AREMA manual. The laboratory testing
was therefore performed in accordance with the specific elements
set forth in Chapter 30, Part 2, and entitled "Evaluative Tests for
Tie Systems".
[0063] The subject composite polymer crossties each weighting
approximately 350 lbs., having dimensions of about 102 inches in
length and cross-sectional dimensions of about 7 inches by 9 inches
were tested. The rails were coupled to the composite polymer
crossties using generic 1:20 cant intervening tie plates with a
contact surface area substantially matching of the railseat
anchored to the crosstie surface using screw-spikes and
Pandrol.TM.-type E2055 rail clips were used to couple the rails to
the generic tie plates. It should be noted that such tie plates
used to couple the rails to the crossties are not considered to
"force-distributing" as they do not substantially increase the
surface where downward force from the rail is applied to the
crosstie. Such tie plates coupled to the crossties are used as
intervening anchoring points for the clips. Holes for receiving
therein the screw-spikes were pre-drilled where the fastener
location was countersunk to accommodate the unthreaded portion of
the screw-spike and the remainder of the hole was drilled at a
smaller diameter for fixture of the threaded portion of the
screw-spike to the crosstie. The smaller diameter portion of the
hole was drilled through and exposed on the opposing side of the
crosstie.
Rail/Plate Area Compression Test
[0064] This test was performed to determine the ability of the
crossties to resist railseat loads. Briefly, the test consists of
applying a vertical load on a pre-determined area. There are two
methods which were used in testing the composite polymer crossties
of the instant disclosure. In any and all cases, the maximum
elastic deformation while under load should not exceed 1/4-inch,
with permanent deformation after release of the compressive force
not exceeding 1/8-inch within 1 minute of releasing the load. The
first method uses the rail itself (i.e. devoid a force-distributing
plate) having a surface area contacting the composition polymer
crosstie of 51/2 inches by 9 inches. The second method uses a
force-distributing plate having a surface area contacting the rail
of 73/4 inches by 14 inches. A pressure, according to the test
parameters, was applied at 900 psi (44,550 lbs.) for the rail only
first method and 921 psi (100,000 lbs.) for the force-distributing
plate second method.
[0065] The results of the Rail/Plate Compression Test are as
follows:
TABLE-US-00001 TABLE 1 Pressure Max. Deflection Applied Deflection
(psi) Sample Tie (psi) (inch) (1 min. @ 0 psi) #1 - Method 1 900
0.165 0.003 (Rail Compression) #2 - Method 2 921 0.193 0.005 (Plate
Compression)
[0066] According to the AREMA testing parameters, the pass/fail
requirements are set at 0.250 inch for max deflection and 0.125
inch for residual deflection. As clearly shown in Table 1 above,
the composite polymer crossties and system disclosed herein passed
the test. Additionally, in the long term, there was no evidence of
permanent deflection. The tester also noted that upon removal of
the compression device, the top surface of the composite polymer
crossties were in pristine condition and this was achieved without
the aid of any protective pad or interim force-distributing plate
of any kind.
Embedded Screw/Spike/Pull-Out Test
[0067] This test was performed to determine the ability of the
crossties to resist withdrawal of the rail fastening system
(spikes). In conducting this test a 61/2-inch long spike is
inserted 41/2-inches into the composite polymer crosstie. A
pull-out load was applied at 1 inch per minute and a minimum
extraction load of 5,000 lbsf (pound force) is required to pass the
test.
[0068] The results of the Embedded Screw/Spike/Pull-out Test are as
follows:
TABLE-US-00002 TABLE 2 Extraction Load Sample Tie (lbsf) #1 15,890
#2 17,300
[0069] As noted above the pass/fail requirement for this test is a
minimum extraction pull-out load of 5,000 lbsf. As show in Table 2,
both sample composite polymer crossties passed the Embedded
Screw/Spike/Threaded Insert Pull-out test and generated values of
at least three times the required minimum.
Spike Lateral Restraint Test
[0070] The Spike Lateral Restraint Test was performed to determine
the ability of a screw-spike to resist lateral movement. Briefly,
the spike is driven in the tie to a normal working depth and a load
is applied laterally to 0.2-inch at a rate of 0.2-inch per minute.
A load/deflection curve is then generated and a maximum load is
recorded. It should be noted, that there is no pass/fail criteria
provided for AREMA for this test.
[0071] The results of the Spike Lateral Restraint Test are as
follows:
TABLE-US-00003 TABLE 3 Load @ 0.2 inch Sample Tie displacement #1
3715 #2 3891
Tie and Fastener System Wear-Deterioration Test
[0072] The Tie and Fastener System Wear-Deterioration Test was
performed to determine railseat deterioration and fastener system
performance in heavy axle load environments due to repeated load.
In this test a complete track system is emulated where two rails
are coupled to the composite polymer crosstie and the crosstie is
solidly fixed to the test bed. This testing was preformed using
standardly shaped polymer crossties of the compositional
embodiments discussed above devoid of the rectangular channel noted
above in one set of tests (noted below as example Tie and Fastener
System Wear-Deterioration Test 1) and in another set of tests using
polymer crossties of the compositional embodiments discussed above
having the rectangular channel milled in the top surface for
receiving the railseat therein (noted below as example Tie and
Fastener System Wear-Deterioration Test 2).
[0073] Briefly, the testing machine comprises a load frame with a
servo-controlled dual action hydraulic actuator. The test load is
distributed through to load arm set at an angle of 27.5 degrees
from vertical. The load is transmitted equally to each of the two
railheads of a full crosstie using the appropriate fastening
system. A load of 65,000 lbsf was cyclically applied to the set-up,
for a lateral top vertical ratio of 0.52. An abrasive environment
must also be simulated on each rail seat for this test.
Accordingly, water drip nozzles were positioned over the field and
gauge sides of each railseat. Clean and dry sand was also spread on
both sides of the railseat.
[0074] To measure static and dynamic lateral head displacement
during the test, a displacement meter was placed behind the
railhead and railbase on each railseat. Deflections were monitored
at regular intervals (500,000 cycles minimum) and tracked
throughout the test to ensure that there was no excessive
movement.
[0075] After completing the pre-test procedures, a head measurement
under static load was taken to establish a benchmark. After
completing the static load measurement, the wear/abrasion test was
initiated and under normal conditions is for either 3,000,000
cycles, or until failure, at a frequency of 2.8 Hz. Any
abnormalities were noted. Upon completion of the wear/deterioration
test, the rail seat assemblies were examined and photographed. The
static load test was then repeated. The dismantled components were
then examined for sign of failure/damage and the rail seat
deterioration maximum depths, if present, were measured.
[0076] In order to pass the test, no deflection during the test
should exceed 0.2000 inches and none of the actual components under
test (in this case the composite polymer crosstie) should fail.
Tie and Fastener System Wear-Deterioration Test 1
[0077] The results of the Tie and Fastener System
Wear-Deterioration Test 1 are as follows. In this set of testing,
standardly shaped polymer crossties (i.e. devoid of a rectangular
channel milled in the top surface for receiving therein the
railseat of a railway rail) were used (not shown in the figures).
The rails were coupled to the polymer crosstie using commonly known
intervening tie plates which were coupled to polymer crosstie by
four screw spikes each. Briefly, the rail rests on the tie plate
and a pair of tie clips interact with the railseat and the tie
plate so as to couple the rail to the polymer crossties in a manner
commonly known in the art for coupling railway rails to wooden
crossties. The test, as noted above, was to be run for at least
3,000,000 cycles with close monitoring of the components for signs
of breakage (failure) of a given component and/or head lateral
displacement of the railhead in excess of 0.200 inch, which would
represent a fail.
[0078] During the test two notable events occurred. Firstly, at
1,423,000 cycles one of the tie plates broke (Tie Plate B) at the
shoulder and therefore allowed for rotation of the rail. Since the
composite polymer crosstie being tested did not fail, the broken
tie plate was changed and the testing resumed. Secondly, at
2,675,00 cycles the tie plate in the same position as the previous
broken tie plate failed and again, allowed for rotation of the
rail. This second broken tie plate was changed and the testing
continued. These breakage points, and leading up to the failure,
can be clearly seen in the lateral head displacement data present
in Table 4, below.
[0079] At the completion of the testing, the components were
assessed and the following observations were made.
[0080] Tie Plates--Tie plate A showed no signs of fatigue fissuring
and was used throughout the test. As noted above, tie plate at
position B required two changes and the cause of the failure was
unknown.
[0081] Rail Clips--All four rail clips performed well and no signs
of permanent deformation where observed.
[0082] Screw-spikes--No damage or signs of failure were noted with
the screw-spikes. Even the spikes that were re-driven with respect
to the tie plate changes at position B performed well.
[0083] Composite Polymer Crossties--The composite polymer crosstie
was examined for signs of wear and deterioration. It is interesting
and surprising to note that, unlike wooden crossties, the surface
of the composite polymer crosstie showed virtually no signs of
abrasion after the fatigue test. The section under the tie plate
which was not directly under the rail was noted by the tester to be
"pristine", thus edges of the tie plates did not dig into the top
surface of the composite polymer crossties whatsoever. Reference
lines drawn on the composite polymer crosstie to center the tie
plates were still visible after the testing. No pitting or abrasion
marks were measured at any location on the tie. Therefore the
composite polymer crossties as disclosed herein have wear
characteristics equal to or better than concrete crossties, which
are significantly more expensive to manufacture. In order to obtain
such wear characteristics with concrete crossties, a cushion mat is
required which was not used in the testing of the instant composite
polymer crossties.
[0084] The composite polymer material from which the crossties were
fabricated created a thread pattern for the spikes which was
extremely effective at holding said spikes even when "re-spiked" to
change the broken tie plate, noted above. Unlike in the maintenance
of conventional wooden (and in some instance concrete) crossties no
filler or epoxy was used in the re-driving of the screw-spikes and
the system did not show any signs of a reduction in the retention
properties of the screw-spikes in the composite polymer
crosstie--thus showing a significant improvement over the
characteristics of conventional wooden crossties. This surprising
property of the composite polymer crossties disclosed herein is
shown with respect the to the lateral head displacement values
noted below in Table 4.
TABLE-US-00004 TABLE 4 Number of Seat A Seat A Seat B Seat B Cycles
Railhead Railbase Railhead Railbase Static Before 0.067 0.017 0.077
0.006 8,000 0.046 0.011 0.046 0.004 50,000 0.046 0.011 0.049 0.006
300,000 0.046 0.009 0.045 0.004 500,000 0.047 0.008 0.045 0.003
800,000 0.049 0.009 0.044 0.003 1,100,000 0.048 0.009 0.058 0.007
.sup. 1,423,000.sup.a 0.052 0.009 0.074 0.003 .sup. 1,425,000.sup.b
0.049 0.009 0.049 0.004 1,700,000 0.049 0.008 0.048 0.006 2,100,000
0.049 0.008 0.048 0.005 2,500,000 0.049 0.008 0.68 0.010 .sup.
2,675,000.sup.c 0.050 0.008 0.075 0.008 .sup. 2,765,000.sup.d 0.052
0.007 0.040 0.008 2,929,000 0.049 0.008 0.043 0.007 Static After
0.055 0.013 0.058 0.013 .sup.aBefore, but close to the above-noted
first tie plate failure .sup.bAfter the above-noted first tie plate
failure .sup.cBefore, but close to the above-noted second tie plate
failure .sup.dAfter the above-noted second tie plate failure
[0085] As shown in Table 4, the lateral head displacement values
for the Static Railhead displacement either maintained initial
values or actually decreased with usage (Static deflection for Seat
A Railhead before=0.067 initial reading vs. Static deflection for
Seat A Railhead after=0.055; Static deflection for Seat B Railhead
before=0.077 vs. Static deflection for Seat B Railhead
after=0.058), unlike with wooden or other conventionally used
crossties. Therefore, the spikes, when used in the instantly
disclosed composite polymer crossties either maintain a
consistently low deflection value or in fact tighten, as opposed to
loosening as is seen and problematic in conventional crossties, by
virtue their composition.
[0086] With respect to the above testing of the composite polymer
crossties used in the instantly disclosed system, it was
surprisingly discovered that the holding properties of the
crossties for the screw-spikes were noted to be exceptional as
compared to conventional wooden crossties. The holding properties
of a given crosstie are correlated through the lateral head
displacement measurements. For example, with the use of
conventional wooden crossties one would expect both higher initial
lateral head displacement values and a higher increase in
deflection values as the crosstie progressed through the test,
which as observed by the data of Table 4, is clearly not the case
with use of the instantly disclosed system. The lateral head
displacement values of the instantly disclosed system remained
substantially constant throughout the testing. Furthermore, as no
cushion mats or surface-area-increasing force-distributing plates
were used in the testing, it was shown that the instantly disclosed
system does not require the use of cushion mats that may erode to
surpass the wear properties od wooden crossties. Also, the abrasion
normally suffered by conventionally used wooden crossties was not
observed. As noted above, following the test, no abrasion of the
composite polymer crossties was seen in the area contacted by the
tie plate/rail.
[0087] Additionally, surprisingly, with reference to Table 4, even
when the Tie Plate B suffered catastrophic failure at 1,423,000 and
2,675,000 cycles, respectively, only a marginal increase in the
lateral head displacement values were observed. This indicates that
the instantly disclosed system may be capable of continuing to
function for a significant number of cycles (or train passes) even
with a broken tie plate. Therefore, an improved safety aspect may
be provided by the instantly disclosed system.
Tie and Fastener System Wear-Deterioration Test 2
[0088] The results of the Tie and Fastener System
Wear-Deterioration Test 2 are as follows. In this set of testing,
polymer crossties having a rectangular channel milled into the top
surface for receiving therein the railseat of a railway rail were
used as is shown, for example in FIGS. 1a to 1c and the assembly as
shown in FIGS. 2a to 3b. No abrasion guards in the rectangular
channel where employed in this testing. The test, as noted above
was to be run for at least 3,000,000 cycles with close monitoring
of the components for signs of breakage (failure) of any components
and/or head lateral displacement of the railhead in excess of 0.200
inch.
[0089] At 2,841,634 cycles it was noted that in a side of the
rectangular channel outward (Seat A Railbase) in the direction of
force from a load arm (i.e. the field-side of the railseat and
rectangular channel), that the railseat had become embedded in the
polymer tie material and the test was stopped.
[0090] Following the completion of the testing, it was noted that
all four of the rail clips performed well and showed no sign of
permanent deformation aside from expected abrasion marks at
expected points. Additionally, the screw spikes showed no signs if
unusual wear or abrasion, however the spike located nearest the
point where the railseat had become embedded in the polymer tie
material was noted to have less resistance when removed compared to
other spikes. The polymer crossties were observed to be overall
structurally sound. No cracking or permanent bending was apparent
at any point on the polymer crossties.
[0091] Surprisingly, contrary to that commonly seen in wooden
crossties, the rectangular channel, created by the milling in the
top surface, did not show any signs of abrasion. Therefore, using
the polymer crossties with a rectangular channel and system as
described herein may maintain toe load by the rail clip compared to
conventional wooden crossties and also such a system appears to be
resistant to a gap being formed between the bottom of the railway
rail and the crosstie as is a known problem with wooden crossties.
Additionally, in the instantly disclosed system, no cushion mats
are located between the railseat and the crosstie as are used with
concrete crossties. These cushion mats are known to flatten and
deteriorate where, similar to wooden crossties, a gap begins to
forms between the bottom of the railway rail and the crosstie as
the cushion mats deteriorate.
[0092] With exception of the spike located nearest the point where
the railseat had become embedded in the polymer tie materials, the
remaining screw spikes retained their high torque values and the
system performed very evenly, without losing any retention
properties of the screw spikes. The instantly disclosed system,
compared to conventional wooden crossties, was extremely efficient
in holding and maintaining the screw spikes through out the
test.
[0093] The results of the nominal head and base displacements as a
function of the number of cycles for Tie and Fastener System
Wear-Deterioration Test 2 are shown below in Table 5.
TABLE-US-00005 TABLE 5 Number of Seat A Seat A Seat B Seat B Cycles
Railhead Railbase Railhead Railbase Static Before 0.095 0.007 0.098
0.018 500 0.052 0.002 0.054 0.005 282,000 0.052 0.003 0.048 0.001
644,000 0.052 0.004 0.049 0.005 950,000 0.052 0.004 0.049 0.005
1,250,000 0.056 0.005 0.050 0.005 1,550,000 0.058 0.005 0.050 0.005
1,850,000 0.068 0.006 0.051 0.005 2,082,000 0.070 0.006 0.051 0.005
2,149,000 0.072 0.005 0.052 0.005 2,456,000 0.078 0.006 0.053 0.005
2,674,000 0.081 0.007 0.051 0.005 2,748,000 0.081 0.007 0.050 0.005
2,841,634 N/A*(>0.063) 0.008 0.050 0.004 Static After N/A N/A
N/A N/A *No value is available because the transducer had reached
its physical limit (extension) when acquiring a max value.
[0094] Therefore, using the instantly disclosed system wherein no
tie plates or cushion mats are utilized and the polymer crossties
have a rectangular channel for receiving therein the railseat of a
railway rail, consistent head displacement values in the 0.050 inch
range were observed (Seat B Railhead of Table 5). The values
returned for Seat A Railhead beginning around 1,550,000 cycles can
be attributed to test design and the railseat embedding in the side
of the rectangular channel outward in the direction of force from a
load arm as discussed above. Accordingly, in some embodiments, an
abrasion guard may be applied in the rectangular channel, as
discussed in more detail above to prevent the railseat from
embedding in the side walls and thus protect the rectangular
channel.
[0095] Compared to conventional wooden crosstie rail coupling
systems and the system tested in Tie and Fastener System
Wear-Deterioration Test 1, the system of Tie and Fastener System
Wear-Deterioration Test 2 utilizes only 2 screw spikes per coupling
of the railseat to the polymer crosstie, as opposed to 4.
Additionally, as noted above, no tie plates or cushion mats were
utilized in Tie and Fastener System Wear-Deterioration Test 2.
Surprisingly, using the system described in Tie and Fastener System
Wear-Deterioration Test 2 and shown in the figures, the results
showed that the polymer crossties of the instant disclosure and the
system of Tie and Fastener System Wear-Deterioration Test 2 were
comparable to the Tie and Fastener System Wear-Deterioration Test
1.
[0096] It is to be understood that the above description it is
intended to be illustrative, and not restrictive. Many other
embodiments will be apparent to those skilled in the art, upon
reviewing the above description. The scope of the invention should,
therefore, be determined with reference to the appended claims,
along with the full scope of equivalents to which such claims are
entitled.
[0097] Although the present invention has been described with
reference to specific exemplary embodiments, it will be evident
that various modifications and changes may be made to these
embodiments without departing from the broader spirit and scope of
the disclosed subject matter as defined by the appended claims.
* * * * *