U.S. patent number 3,890,904 [Application Number 05/402,299] was granted by the patent office on 1975-06-24 for railway system.
Invention is credited to Lawrence K. Edwards.
United States Patent |
3,890,904 |
Edwards |
June 24, 1975 |
Railway system
Abstract
A railway system comprising a beam supported at spaced intervals
along its length and having tracks extending longitudinally thereof
at opposite sides, with cars adapted to travel on the tracks in
paths along opposite sides of the beam. Eack track comprises a
lower rail and an upper rail extending longitudinally of the beam
at the respective side of the beam. Each car has lower wheels
traveling on the head of the lower rail and an outrigger extending
laterally from the car to the upper rail having a traveling
tension-transferring interconnection with the head of the upper
rail for holding the car upright. The heads of the two rails of
each track lie in a plane inclined to the longitudinal vertical
plane of the beam with substantially all of the beam below the said
inclined plane. The system as disclosed further involves a special
switching arrangement for the tracks, a special station feature
based on the provision of an elevator in the car, and a special
expansion joint between rail ends.
Inventors: |
Edwards; Lawrence K. (Palo
Alto, CA) |
Family
ID: |
23591352 |
Appl.
No.: |
05/402,299 |
Filed: |
October 1, 1973 |
Current U.S.
Class: |
104/121; 104/118;
105/141; 105/147; 105/144; 238/227; 104/130.04 |
Current CPC
Class: |
E01B
25/00 (20130101); B61B 5/02 (20130101); Y02T
30/00 (20130101) |
Current International
Class: |
E01B
25/00 (20060101); B61B 5/02 (20060101); B61B
5/00 (20060101); E01b 025/08 () |
Field of
Search: |
;104/118,130,121,122,120,147R,89 ;105/147 ;238/227 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wood, Jr.; M. Henson
Assistant Examiner: Keen; D. W.
Attorney, Agent or Firm: Koenig, Senniger, Powers and
Leavitt
Claims
What is claimed is:
1. A railway system comprising a beam, a track extending
longitudinally of the beam along one side of the beam, said track
comprising a lower rail extending longitudinally of the beam
adjacent the bottom of said side of the beam and an upper rail
extending longitudinally of the beam adjacent the top of said side
of the beam, each rail having a head, said side of the beam being
inclined downwardly and outwardly from top to bottom of the beam,
the lower rail projecting upwardly and outwardly from said inclined
side of the beam adjacent its bottom and the upper rail projecting
outwardly from said inclined side of the beam adjacent its top with
the heads of the rails displaced laterally as well as vertically
and lying in an inclined plane spaced outwardly from and lying
above said inclined side of the beam with substantially all of the
beam lying below said inclined plane of the rail heads, a car
adapted to travel on the track alongside the beam, means at the
side of the car toward the beam for supporting and guiding the car
on the head of the lower rail, and means extending from the car
above said inclined plane of the rail heads interconnecting the car
and the head of the upper rail for holding the car against
overturning, substantially all of the car being above said inclined
plane of the rail heads.
2. A railway system as set forth in claim 1 wherein the car
supporting and guiding means comprises inclined wheels that engage
the head of the lower rail, one wheel ahead of the center of the
car and one wheel behind the center of the car, said lower rail and
wheels being in a plane inclined to the vertical oppositely from
the inclined plane of the rail heads.
3. A railway system as set forth in claim 1 wherein the beam is of
triangular form in cross section, having a base and inclined sides
converging to an apex, the first track being on one of said sides,
the beam having a second track on its other side comprising lower
and upper rails symmetrically opposite the lower and upper rails of
the first track, the heads of the lower and upper rails of the
second track lying in a second plane inclined oppositely to the
inclined plane of the rail heads or the first track with
substantially all of the beam lying below said second plane, the
two upper rails projecting outwardly in opposite directions
adjacent said apex.
4. A railway system as set forth in claim 3 having second and third
beams meeting at a junction with the first beam and each
corresponding to the first beam, the tracks of all the beams being
generally at the same angle of inclination, first means for
switching cars between the first track of the first beam and the
first track of the second beam or the first track of the third
beam, and second means for switching cars between the second track
of the first beam and the second track of the second beam or the
second track of the third beam.
5. A railway system as set forth in claim 3 wherein the lower rails
are structural elements of the beam and constitute lower chords
situated at lower corners of the beam and the upper rails are
structural elements of the beam and constitute an upper chord for
the beam at the apex.
6. A railway system as set forth in claim 1 wherein the center of
gravity of the car is so situated relative to the head of the upper
rail as to cause the car to tend to rotate away from the beam under
all normal conditions, the car being held against overturning by
means of a traveling tension-transferring interconnection with the
head of the upper rail, the weight of the car having a vector
generally in the plane of the lower rail and a tension vector in
said interconnection, said vectors forming a triangle with said
inclined plane of the rail heads.
7. A railway system as set forth in claim 6 wherein the
tension-transferring interconnection comprises at least one roller
which engages an inward-facing surface on the head of the upper
rail.
8. A railway system as set forth in claim 7 wherein there are a
plurality of rollers, some above and some below the web of the
upper rail.
9. A railway system as set forth in claim 8 wherein the several
rollers are mounted on a common carriage, which carriage partially
encircles the head of the upper rail.
10. A railway system as set forth in claim 9 wherein there is also
mounted on the carriage a device to collect electrical power from a
third rail mounted in proximity to the head of the upper rail.
11. A railway system as set forth in claim 10 wherein the third
rail is mounted on the bottom of the web of the upper rail, and is
connected to an electrical power bus at periodic intervals along
the track.
12. A railway system as set forth in claim 1 wherein the
tension-transferring interconnection comprises means enabling
transition of the upper and lower rails to different relative
displacements while retaining the car erect.
13. A railway system comprising a beam, a track extending
longitudinally of the beam, said track comprising a lower and an
upper rail extending longitudinally of the beam, each rail having a
head, the heads of the rails lying in a plane inclined to the
longitudinal vertical plane of the beam with substantially all of
the beam below said inclined plane, wherein the beam has a second
track comprising third and fourth rails symmetrically opposite the
first and second rails, the heads of the third and fourth rails
lying in a second plane inclined oppositely to the first plane with
substantially all of the beam below said second plane, wherein the
lower rails are structural elements of the beam and constitute
lower chords situated at lower corners of the beam and the upper
rails are structural elements of the beam and constitute an upper
chord for the beam, and wherein the beam has three shear-carrying
webs in isosceles triangle arrangement, each web connecting two of
the chords.
14. A railway system comprising a beam, a track extending
longitudinally of the beam, said track comprising a lower and an
upper rail extending longitudinally of the beam, each rail having a
head, the heads of the rails lying in a plane inclined to the
longitudinal vertical plane of the beam with substantially all of
the beam below said inclined plane, having a car adapted to travel
on the track, means for supporting and guiding the car on the head
of the lower rail, and means interconnecting the car and the head
of the upper rail for holding the car against overturning,
substantially all of the car being above said plane, wherein the
car supporting and guiding means comprises inclined wheels that
engage the head of the lower rail, one wheel ahead of the center of
the car and one wheel behind the center of the car, and having
hooks along side each wheel, said hooks extending generally
downward parallel to the plane of the wheel and inclined toward
each other, partially encircling the head of the lower rail.
15. A railway system comprising a beam, a track extending
longitudinally of the beam, said track comprising a lower and an
upper rail extending longitudinally of the beam, each rail having a
head, the heads of the rails lying in a plane inclined to the
longitudinal vertical plane of the beam with substantially all of
the beam below said inclined plane, having a car adapted to travel
on the track, means for supporting and guiding the car on the head
of the lower rail, and means interconnecting the car and the head
of the upper rail for holding the car against overturning,
substantially all of the car being above said plane, wherein the
center of gravity of the car is so situated relative to the head of
the upper rail as to cause the car to tend to rotate away from the
beam under all normal conditions, the car being held against
overturning by means of a traveling tension-transferring
interconnection with the head of the upper rail, and wherein there
is one tension-transferring interconnection ahead of the center of
the car and one such interconnection behind the center of the car,
with each interconnection being capable of extension and
retraction, and means adapted to cause one to extend as the other
retracts.
16. A railway system as set forth in claim 15 wherein the said
means comprises a hydraulic cylinder in each interconnection, and a
hydraulic connection between the two hydraulic cylinders.
17. A railway system comprising a beam, a track extending
longitudinally of the beam, said track comprising a lower and an
upper rail extending longitudinally of the beam, each rail having a
head, the heads of the rails lying in a plane inclined to the
longitudinal vertical plane of the beam with substantially all of
the beam below said inclined plane, having a car adapted to travel
on the track, means for supporting and guiding the car on the head
of the lower rail, and means interconnecting the car and the head
of the upper rail for holding the car against overturning,
substantially all of the car being above said plane, wherein the
center of gravity of the car is situated relative to the head of
the upper rail as to cause the car to tend to rotate away from the
beam under all normal conditions, the car being held against
overturning by means of a traveling tension-transferring
interconnection with the head of the upper rail, and wherein the
said interconnection is mounted to move up and down relative to the
car, adapting it to various heights of the head of the upper rail
relative to the head of the lower rail.
18. A railway system as set forth in claim 17 wherein the
up-and-down motion is generally rotational about an axis adjacent
the intersection between the plane of the car's wheels and a
vertical longitudinal plane including the center of gravity of the
car.
19. railway system comprising a beam, a track extending
longitudinally of the beam, said track comprising a lower and an
upper rail extending longitudinally of the beam, each rail having a
head, the heads of the rails lying in a plane inclined to the
longitudinal vertical plane of the beam with substantially all of
the beam below said inclined plane, wherein the beam has a second
track comprising third and fourth rails symmetrically opposite the
first and second rails, the heads of the third and fourth rails
lying in a second plane inclined oppositely to the first plane with
substantially all of the beam below said second plane, having
second and third beams meeting at a junction with the first beam
and each corresponding to the first beam, the tracks of all the
beams being generally at the same angle of inclination, first means
for switching cars between the first track of the first beam and
the first track of the second beam or the first track of the third
beam, and second means for switching cars between the second track
of the first beam and the second track of the second beam or the
second track of the third beam, wherein each switching means has
two tracks and wherein the four tracks of the switching means, in
transverse cross-section, are disposed two on one side and two on
the other of triangles of progressively increasing size.
20. A railway comprising a beam, a track extending longitudinally
of the beam, said track comprising a lower and an upper rail
extending longitudinally of the beam, each rail having a head, the
heads of the rails lying in a plane inclined to the longitudinal
vertical plane of the beam with substantially all of the beam below
said inclined plane, wherein the beam has a second track comprising
a third and fourth rails symmetrically opposite the first and
second rails, the heads of the third and fourth rails lying in a
second plane inclined oppositely to the first plane with
substantially all of the beam below said second plane, having
second and third beams meeting at a junction with the first beam
and each corresponding to the first beam, the tracks of all the
beams being generally at the same angle of inclination, first means
for switching cars between the first track of the first beam and
the first track of the second beam or the first track of the third
beam, and second means for switching cars between the second track
of the first beam and the second track of the second beam or the
second track of the third beam, and wherein a third rail for power
distribution is mounted beneath the upper rail of each of the four
tracks throughout the switching area.
21. A railway system comprising a beam, a track extending
longitudinally of the beam, said track comprising a lower and an
upper rail extending longitudinally of the beam, each rail having a
head, the heads of the rails lying in a plane inclined to the
longitudinal vertical plane of the beam with substantially all of
the beam below said inclined plane, wherein the beam is elevated
above a floor of a station, and wherein a car has an elevator
adapted, when the car is stopped at the station, to descend to said
floor for ingress and egress of passengers, and having guard means
at said station for keeping people out from under the descending
elevator, said guard means extending upwardly from said floor to a
height sufficient to exclude people from the area under a
descending elevator, and being movable downwardly by the elevator
as it descends.
22. A railway system comprising a beam, a track extending
longitudinally of the beam, said track comprising a lower and an
upper rail extending longitudinally of the beam, each rail having a
head, the heads of the rails lying in a plane inclined to the
longitudinal vertical plane of the beam with substantially all of
the beam below said inclined plane, having expansion joints in gaps
between the ends of successive rails, each rail having a base, a
web and a head, each expansion joint occupying the gap between the
ends of two rails and comprising an end extension for one of the
two rails and an end extension for the other, each extension being
secured at one end to the end of the respective rail and extending
across the gap toward the end of the other rail, each extension
having a web with an inside face in sliding engagement with the
inside face of the web of the other extension, with the webs of
said extensions generally aligned with and extending between the
ends of the webs of the two rails, the webs of said extensions
having slidably interengaged longitudinal interconnections at their
said inside faces for transmission of loads perpendicularly to the
length of the webs of the extensions in the plane of the latter,
each extension further having a head on its web in extension of the
head of the respective rail, the head of each extension extending
from adjacent the end of the respective rail toward but terminating
short of the end of the other rail, and the heads of the extensions
having opposed angled ends at an expansion gap therefor.
23. In a railway system, a common track and first and second branch
tracks, a car adapted to travel on the tracks, and switch means for
switching the car for travel either on the common and first branch
tracks or the common and second branch tracks, each of said tracks
comprising a pair of rails, means supporting the rails of said
tracks with the rails displaced both vertically and laterally
relative to one another so that the heads of the rails lie in an
inclined plane, said supporting means lying substantially wholly
below said inclined plane, said switch means comprising a first
pair of fixed switching rails associated with the first branch
track, a second pair of fixed switching rails associated with the
second branch track, and a pair of movable rails for switching the
car between the common track and first pair of fixed switching
rails and between the common track and the second pair of fixed
switching rails, and means supporting the fixed and movable
switching rails with these rails displaced both vertically and
laterally relative to one another and lying in substantially the
same inclined plane as said common and branch tracks, the movable
switching rails being movable in said inclined plane, said car
having means for supporting and guiding it on the lower of each of
said pairs of rails, and means extending from the car above said
inclined plane for interconnecting the car and the upper of each of
said pairs of rails for holding the car against overturning.
24. In a railway system as set forth in claim 23, said movable
switching rails being short in length relative to said fixed
switching rails.
25. In a railway system as set forth in claim 23, each of said
common track and said first and second tracks being on a beam, said
beams meeting at a junction.
Description
BACKGROUND OF THE INVENTION
This invention relates to railway systems, and more particularly to
a mass transit railway system especially adapted for installation
as an elevated system in urban areas.
The invention is generally in the same field as the systems shown
in the following prior U.S. Patents: Nos. 841,653, 904,526,
3,096,728, 1,167,892, 3,083,649, 3,122,105, 3,194,179, 3,238,894
and 3,457,876.
SUMMARY OF THE INVENTION
Among the several objects of the invention may be noted the
provision of an improved railway system of a type in which cars are
adapted to travel on one or both sides of a beam; the provision of
such a system involving a modular construction that permits
relatively efficient, rapid and economical erection and removal of
system components; the provision of such a system which is of
economical construction, which is adapted to various layouts, and
which is easy to maintain; the provision of such a system which
enables ready incorporation of a "third rail" for transmission of
electric power to a car; the provision of an efficient switching
arrangement for such a system, and particularly one that enables
two-way traffic; the provision of an improved station accommodation
for an elevated system based on the provision of an elevator in the
car; and the provision of an improved expansion joint especially
useful in the system.
In general, the system involves the provision of a beam with a
track extending longitudinally of the beam comprising a lower rail
and an upper rail extending longitudinally of the beam. In
accordance with the invention, the heads of the rails lie in a
plane inclined to the longitudinal vertical plane of the beam with
substantially all of the beam below the said inclined plane. A car
is adapted to travel on the track, and for two-way traffic, the
beam may have a second track corresponding to the first on its
other side. Other objects and features will be in part apparent and
in part pointed out hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 (sheet 1) is a side elevation of a fragment of an elevated
railway system of this invention;
FIG. 2 (sheet 1) is an end view of FIG. 1, showing a car on one
side of the beam of the system;
FIG. 3 (sheet 1) is a perspective of a fragment of the system
showing a car with parts of the car broken away;
FIG. 4 (sheet 2) is a vertical transverse section of the beam, on a
larger scale than FIG. 2;
FIG. 5 (sheet 1) is an enlarged detail view showing a lower
rail;
FIG. 6 (sheet 3) is an enlargement of the upper part of FIG. 4,
showing further detail;
FIG. 7 (sheet 4) is a transverse section showing a lower wheel and
an outrigger of a car;
FIG. 7A (sheet 4) is a view generally on line 7A--7A of FIG. 7;
FIG. 8 (sheet 5) is a plan of the outrigger shown in FIG. 7;
FIG. 9 (sheet 5) is a view taken generally on line 9--9 of FIG.
8;
FIG. 10 (sheet 2) is an enlarged fragment of FIG. 7;
FIG. 11 (sheet 6) is a plan view illustrating a switching
arrangement of this invention;
FIG. 11A (sheet 7) is a continuation of FIG. 11;
FIG. 12 (sheet 6) is a side elevation of FIG. 11;
FIG. 12A (sheet 7) is a side elevation of FIG. 11A;
FIGS. 13-16 (sheet 6) are vertical transverse sections on lines
13--13 to 16--16 of FIG. 11;
FIG. 17 (sheet 8) is a view of a station of this invention;
FIG. 18 (sheet 9) is a plan of an expansion joint of this
invention;
FIG. 19 (sheet 9) is a side elevation of the FIG. 18 joint;
FIG. 20 (sheet 9) is a side elevation of one member of the
joint;
FIG. 21 (sheet 9) is a bottom plan of FIG. 20; and
FIGS. 22-24 are sections on lines 22--22 to 24--24 of FIG. 19.
Corresponding reference characters indicate corresponding parts
throughout the several views of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As noted above, this invention relates to a mass transit railway
system, especially adapted for installation as an elevated system
in urban areas. It features a slender common guideway, which may be
double-tracked for two-way traffic, compatibility with a practical
switch, avoidance of elevated stations in residential areas, and a
modular construction that permits speedy erection or removal of the
fixed installations. Additional advantages are economical
construction, flexibility of layout, easy maintenance, and easy
accommodation of a "third rail" for electrical power.
A key element of the system as herein illustrated is a triangular
beam with a rail at each apex, which rails constitute the primary
structure of the beam in addition to serving as rails for support
and guidance of cars. At each lower corner of the triangle is a
rail for support of the cars; at the top of the triangle are a pair
of rails, essentially back-to-back, each of which is interengaged
by tension means extending from the car to hold the car upright.
The webs of the beam may be either perforated or unperforated,
depending on the preference of the user. In either event, they
carry shear loads which arise from deadweight of the passing cars,
torsion due to unsymmetrical loading, and deadweight of the beam
itself.
In the preferred embodiment, the beam is constituted by
prefabricated elements or modules, approximately 20 meters long,
for example, laid end-to-end, with their ends resting on columns or
supports which may be of various suitable configurations. As an
expansion joint is desirable between most beams, there is no
arrangement to transfer bending moments or vertical shear from beam
to beam. In curves, the beam is banked or superelevated to the
appropriate angle, and the length of the beam module is typically
shortened (perhaps to 12 meters, for example) to accommodate the
extra loads. Transition beam components are needed at the beginning
and end of curved stretches, for reasons well known in the railroad
art.
Cars pass along the side of the beam, traveling singly or in
trains. It is contemplated that these cars will have an on-board
operator and very little reliance on computers or other automatic
controls; however, this choice has no bearing on the present
invention. Each car has two slanting wheels near the bottom of the
car and close to that wall of the car nearest the beam, which
wheels are preferably steel-rimmed and double-flanged to engage
positively with the railhead. Propulsion and braking of the car is
exclusively through these two wheels. For most applications, it
appears desirable that these wheels and the associated
motor/clutch/geardrive/braking elements comprise a module that is
installed in and removed from the car as a unit, that the entire
module be spring-mounted to the car body, that the wheel not be
steerable relative to the car body, and that the wheel incorporate
elastic inserts between rim and hub in order to absorb sound and
vibrations. These details do not affect the basic invention,
however.
Inasmuch as the car's center of gravity is significantly offset
from the main wheels, it is necessary to make provision for
preventing the car from falling away from the beam. This is
accomplished by use of a tension means or "outrigger" extending
from the car body above each main wheel to engage the upper rail,
as noted above. The means of engagement may be rollers or slides,
for example, and they may straddle the railhead or pass inside a
special C-shaped railhead. The preferred embodiment uses a
multiplicity of rollers in a modified whiffletree arrangement to
carry the load without excessively large rollers or wheels.
The overturning moment on the car due to force of gravity is large
and relatively invariant. Consequently, there is no need to provide
additional rollers or the like to prevent the car from tipping in
the opposite direction.
In cross section, the car's main wheels and outriggers are arranged
to direct loads toward the corners of the beam, thereby minimizing
the need for secondary structure in the beam's section. The webs
and heads of the beam rails are oriented more or less symmetrically
in line with these vectors. The outrigger load vector, being in
tension, permits the use of occasional universal joints in the
outrigger for ease of alignment and accommodation of tolerances.
The outrigger vector could be horizontal; however there may be some
advantage in having it on a gentle slope, the main benefit being
that this causes the wheel loads to increase somewhat, thereby
improving traction for propulsion and braking. Some rail transit
systems have been marginal in this respect, especially in rainy
weather; the configuration shown herein is believed to afford an
improvement of nearly 20% over the best duorail systems.
The construction described above is adequate for system
applications where the car is entered from the outboard side or, in
fact, any direction other than the beam side. However, studies have
shown considerable merit in an arrangement where the station is
placed "between the tracks", e.g., between oppositely bound trains,
so that one platform can serve both. This feature requires a
departure from the basic beam configuration at stations involving
an increase in beam height to make it possible for passengers to
enter the car from the "beam side" without having to stoop
underneath the upper rail, with a corresponding change in
load-vector arrangements.
Other system studies have indicated that there is virtue in
ground-level stations so arranged that there is no need to bring
the beam down to ground level. A possible solution to this is to
incorporate an elevator into the car.
Another attractive adjunct is the ability to service the beam and
switches without resorting to (a) ground-level service vehicles and
the associated ladders or other elevating devices, or (b) service
vehicles that travel along the guideway as passenger cars do,
thereby complicating the normal passenger service. This is feasible
by keeping the inside of the beam and switches clear as a
passageway for maintenance personnel. By the same token, power
lines and communication wires for the system can be mounted inside
the beam and still be readily reached for maintenance or
repairs.
With regard to the car's outrigger, it is necessary that this
device satisfy several criteria as follows: First, to permit
negotiation of horizontal curves, it is necessary that the group of
outrigger rollers (or analogous slide or magnet) must be able
generally to swing about a vertical axis relative to the car. In
addition, it is necessary that certain rollers shift relative to
the others to conform to the local curvature without roller
overloading. (A slide, if used, must actually flex to avoid
excessive localized bearing pressures.) Second, to accommodate
vertical curves, it appears desirable to permit freedom about a
horizontal axis analogous to that just discussed; this problem may
be alleviated by using a somewhat greater radius for vertical
curves. Third, it is desirable to minimize the cross-sectional
dimensions of the roller or slide in order to minimize the section
of the upper rail combination and also to simplify the design of
the switch. To permit universal joints as already discussed, it is
also desirable that the general assembly of rollers (or slides) be
self-aligning about all three axes and in the vertical direction as
well. It must also be fixed relative to the car in the transverse
and longitudinal directions. Fourth, to avoid twisting the car as
it negotiates the transition sections at the ends of curves, the
two outriggers on each car must be coordinated so that one extends
laterally as the other retracts laterally; thus the pair of
outriggers maintain the desired rotational position of the car
relative to the beam, without twisting the car itself. The present
invention satisfies all of these criteria. It may be advantageous
to provide a protected passage for the outrigger, possibly making
the system less vulnerable to adverse weather, animals, vandalism,
and accidental blockage, and to use one or more magnets on the
outrigger to provide most or all of the required tension force. Use
of these arrangements makes it virtually impossible to "derail" the
outrigger from the upper rail because one nearly surrounds the
other. The present invention may also provide for positive
engagement between the car and the lower rail, by the use of hooks
alongside the main wheels System studies shown that, with realistic
turning radii and reasonable wheelbase in the car, there is no need
to move these hooks in turns; i.e., they may remain fixed relative
to the wheel axle.
It is desirable that the outrigger should at all times point its
vector toward the intersection between the main wheel vector and a
vertical line (or more correctly, a vertical plane) through the
car's center of gravity. To accomplish this, it is desirable that
the outrigger be attached to the car by means of a hinge located at
this point. While this may be feasible in certain special
applications such as freight trains, the present configuration is
such that the hinge point falls near the center of a passageway.
While a vertical hinge such as four-bar linkage may be used, the
preferred arrangement utilizes a curved track (or pair of tracks)
in the available space closer to the car's inboard walls, as will
appear. This curved track is configured and positioned so as to
form a radius about the desired hinge point. Thus the outrigger,
with a roller or slide at its inboard end, will transmit the
tension vector to the car in the desired manner. Studies show that
it has a powerful self-centering action. Continuing the discussion
of car-to-beam relationships, it is plain that, within rather broad
limits, the bottom of the car could be substantially above or below
the bottom of the beam. Plainly, in densely built-up areas, both
must be at least high enough above street intersections to clear
trucks and buses, i.e., about 4.5-5 meters, for example, above
street level. An arrangement with the two bottoms essentially
co-planar, has the following advantages:
short columns and easy erection of the guideway;
minimum interference with overhead wires, which run generally
horizontally;
minimum vertical dimension in the clearance passage when the system
penetrates buildings: it is especially advantageous to confine this
penetration to a single story of a building;
small, convenient tunnel cross section;
small vertical clearance increment between two crossing lines of
the same system;
short stairways for passengers; short travel for elevators;
minimum overturning moments imposed on columns and foundations due
to wind loading on the combination of guideway and cars: (the
present arrangement reduces the magnitude of the wind force as well
as its moment arm above the ground.);
passengers can "see out" on both sides of the car: (the top of the
beam is approximately at eye level of seated passengers.).
As will be discussed further, considerations of switching impose a
clearance requirement on the car such that nothing on the car
should penetrate the envelope schematically illustrated by the
phantom line X in FIG. 4. The vertical portion of the line is
dictated by (and is a function of) such practical matters as
clearance between cars traveling on opposite sides of the beam,
clearance at stations, and the like. The envelope is penetrated
locally at the outrigger and at the main wheels; these
penetrations, in turn, become constraints on the design of the
remainder of the system, particularly the switch.
The preferred embodiment of the system employs conventional
electric propulsion of the cars, with associated regenerative
braking, substantially in line with modern practice in rapid
transit lines and streetcars. This requires "third rail" power
transfer from the guideway to the cars. FIG. 6 shows the preferred
arrangement in cross section, with a third rail for each direction
of traffic. These third rails are fastened to the upper primary
rails (with insulation therebetween) at intervals of perhaps 1
meter, for example. The main power conductor, which services both
directions of traffic, may be secured inside a steel protective
enclosure, which is an integral element of the beam structure.
Cross-feed between the main power conductor and the individual
third rail is located at the joint from one beam module to the
next, and may employ relays, fuses, and other devices according to
the preference of the electrical system designer. Power is picked
up by the car via a roller or wiper affixed to the outrigger
carriage. Placement of the upper rail with its web generally
horizontal, in conjunction with a sloping outrigger vector, affords
extra space between the rail web and the lower rollers, which space
is desirable to assure sufficient electrical gap around the third
rail. This placement of the third rail was selected after
considering many factors including moisture condensation; adverse
weather; accumulation of grime; inspection and clearing; accidental
damage to the beam; mechanical and electrical convenience;
electrical hazard to workers, passengers, and animals; and
compatability with the switch.
A gap is preferably provided between the bases of the opposite
upper rails (as appears in FIG. 6). This gap permits extension of
utility standards or the like upward from the center of the beam.
It also permits solid mounting of a weather shield (shown in FIG.
6) and permits a strong, rugged connection between the rails and
the remainder of the beam structure, particularly in the presence
of transverse loads imposed on the rails. To facilitate this
construction it may be necessary to incorporate transverse
bulkhead-like members (not shown) at spaced intervals along the
beam, which members are attached to both rails and possibly to the
protective enclosure.
In a preferred arrangement, the car has some twenty seats, the
majority of which are in pairs facing the direction of travel. A
longitudinal passageway is included to provide for standees, to
facilitate emergency escape, and to minimize the number of external
doors on the car. This passageway is placed closer to the beam than
the double seats, to assure that dense loads (i.e., standing
passengers) are closer to the beam than the low-density loads
(i.e., seated passengers). Additional seats are placed inboard of
the passageway; system studies show that bench-type seats have
several incidental advantages over single seats facing forward.
These additional seats occupy the longitudinal space between the
wheels, except for space at the inboard doorway. The wheels and
their associated motor/geardrive/clutch/brakes are preferably
assembled into a module which is in effect a "one-wheel truck"
where truck is used in the lexicon of U.S. rapid transit,
synonymous with "bogie" in Europe. This module or truck is mounted
to the car body so that there is restrained vertical freedom
between the two. There is no need for the truck to rotate relative
to the car about any axis; this is a considerable simplification in
comparison with conventional rail transit vehicles. Provision is
preferably made for vertical freedom of the truck while restraining
the truck in two directions and three rotational axes. Details of
the geardrive, clutch, and brakes may be chosen from any of several
well-known methods. Further, the wheel may incorporate elastic
inserts between the hub and the rim; again, there are several
existing solutions from which to choose. It is evident that this
arrangement keeps the heaviest single element of the car, i.e., the
truck, very close to the center of the beam to minimize overturning
moments. Such measures reduce demands on the beam, columns, and
foundations in terms of rigidity as well as strength. Also, it may
be desirable to transfer the vertical load between truck and car in
a flexible, damped manner, and also to incorporate load-leveling
features. Components for this purpose may be enclosed in a portion
of the car body which has structural as well as safety/cosmetic
functions to perform. This enclosure may include removable panels
inside the car for convenient inspection and servicing of said
components while they are in place.
Doors and windows of the car are conventional and are incidental to
the present invention. To take advantage of a "center platform"
station, as already discussed, an inboard door is favored. This
also facilitates emergency escape, particularly in tunnels or above
bodies of water.
Couplings from car-to-car can be of modern rapid-transit design,
with integral electric circuits and possible pneumatic connections
as well. Placement of the couplings beneath the end door sills
appears to be superior to the other locations studied, particularly
from the standpoint of impact on the car-to-car passageway. In the
preferred arrangement, which has an elevator at the front of the
lead car, it does not appear practical (or necessary) to
incorporate a coupling at the front of the lead car. However, it is
desirable to incorporate an air-bag anticollision device on the
front of the lead car and to provide mating surfaces on the rear of
every car to cooperate with this air-bag.
The general section of the beam could be a truncated isoceles
triangle (i.e., a four-sided figure with sloping sides and
horizontal top and bottom), for example. However, this may
compromise the structural simplicity of the beam and, in
particular, may introduce the need for shear-carrying elements in
the cross section. Such elements may be objectionable not only
because of their cost and weight but also because they would tend
to block the internal service passageway. Furthermore, if the two
upper rails are moved a substantial distance apart, there may be a
loss in their combined stability as compression members. (These
rails are preferably the main compression-carrying elements for
general beam bending under gravity loads.) Finally, such a section
would force the massive elements of the car to be located farther
from the center of the beam, adding to loading on the columns and
foundations as well as the beam itself.
The webs of the beam, i.e., the shear-carrying elements on the
three sides, may be "porthole" elements as will appear. However,
the webs could be thin solid panels (probably gaining structural
efficiency at significant cost in attractiveness, internal
servicing convenience, and possibly noisiness) and could even
consist of thin-webs-plus-stiffeners. They could also be classical
truss-like elements or a lattice of diagonal elements achieving the
same result in conjunction with suitable stiffeners.
Hand and computer analyses have shown that, as the car moves along
the beam, deflections at the car's center of gravity (i.e., some
one and one-half meters, for example, from the center of the beam)
are dominated by two phenomena: first, bending of the beam module,
as governed by its length and the amount of cross section in the
steel rails; and second, twisting of the beam module, as governed
by the shear rigidity of its three webs. Studies also show that,
when these two contributions are essentially equal, there is almost
no interaction between two cars (or trains) passing along opposite
sides of the beam and dynamic problems are minimized. As a
practical matter, this desirable result can be achieved by
judicious design of the webs.
The connection from beam module to beam module has been studied and
it appears desirable to minimize the structural interdependence
first, because there is no practical way to avoid expansion joints
in long, straight runs of elevated track and second, because it is
desirable to replace a damaged beam module with a minimum of
intricate work at the job site. Studies indicate that the critical
consideration in alignment from one beam module to the next is the
lateral alignment of the upper rails. Misalignment here,
particularly in conjunction with expansion-joint gaps up to 15 mm.,
could be harmful to the rollers of the outrigger. Therefore, it is
proposed to couple one beam module to the next in the vicinity of
the upper rails, with a coupling that transfers lateral shear but
does not interfere with expansion. Studies suggest that the
coupling can be so installed as to introduce a "step-down" or
horizontal offset from one beam module to the next which varies
according to the width of the expansion gap, and is matched to the
roller radius. For example, with a roller radius of 55 mm. and a
gap of 15 mm., the ideal step-down is approximately 2 mm. This
offset can decrease linearly to zero as the expansion gap closes,
to minimize wear and noise. The same mechanical arrangement is
appropriate for reverse traffic on the opposite side of the beam;
however, this should not be attempted when it is desired to run
trains in reverse at high speed, as in shuttle applications.
As will be discussed below, there is advantage in transferring
longitudinal loads from one beam module to the next. The
load-transfer device must resist rapid loading, such as takes place
when trains accelerate and decelerate, but must not resist gradual
changes in the spacing from beam module to beam module due to
temperature fluctuations. This may be accomplished by introducing a
special piston-and-cylinder device generally similar to a hydraulic
actuator but without external hydraulic ports or controls. Instead,
there are chambers on either side of the piston. With a restricted
passage through (or around) the piston and a "fluid" that creeps at
a very slow rate, these contrasting requirements are satisfied. The
fluid can be a very viscous substance such as pitch or a suitable
silicone. The piston is attached to one beam module and the
cylinder to the other, to transfer the loads in this manner.
Practical considerations dictate that the piston pass through both
ends of the cylinder, so that the combined volume of the two
chambers is always the same, regardless of the extension. Thus, the
volume of contained fluid is always the same, and external fluid
storage is avoided. This device is preferably located at the center
of the beam section, above or below the service passageway.
The columns may generally be of conventional construction, either
concrete or steel, although steel construction may provide a more
slender appearance. Normally, one column is placed beneath each
beam module-to-module joint. Studies show that, for realistic
weight and proportions of beam modules and cars, it will be
necessary to fasten the beam module down at each of its four
"corners" (as seen in plan view) regardless of design criteria for
wind and earthquake loads. This is preferably accomplished by a
group of vertical bolts at each corner of the beam module; this
means, in turn, that there are four corners and four groups of
tiedown bolts at each column. The attachment must also accommodate
expansion in the gap from beam module-to-module, perhaps as much as
20 mm. In order that braking and acceleration loads may be
transferred from beam module to column, at least one of the two
beam modules must be longitudinally constrained to the column.
As previously discussed, it is advantageous to transfer the
(relatively small) transverse shear loads from one beam module to
the next via a special coupling. Therefore, only one of the two
modules should be anchored transversely to the column. There are
many obvious ways to accomplish this while satisfying the other
constraints just discussed.
An elastic insert between the beam modules and the columns may be
helpful to reduce noise, and can also assist in "smoothing the
ride". Such elasticity, however, must not permit sloppiness in the
vertical or lateral alignment from one beam module to the next, or
rolling noise and possibly other difficulties would be encountered.
It appears preferable, therefore, to anchor the two adjacent beam
modules down to a common steel block, which block is prevented from
rotating about a transverse axis (i.e., transverse to the beam) by
the nature of the beam-to-block attachment itself, preferably by
engagement of the tie-down bolts discussed previously. Such a block
is situated at the outboard extremity of the column's cross-head,
and the elastic insert appears between the cross-head and the
block. Additional features may be incorporated in the block
installation to provide fail-safe metal-to-metal engagement in the
event of failure of the elastomer, to provide vertical adjustment
for tolerance accumulation or slight settling of the foundation and
to permit all metal-to-elastomer bonding to be done in the
factory.
At the base of the column, the preferred arrangement involves a
horizontal concrete or steel pad to support the column, with a
multiplicity of projecting vertical studs to permit anchoring the
base of the column. Selective shimming at the interface permits
adjustment of the vertical position of the column and/or transverse
and longitudinal adjustment of the top of the column, to allow for
assembly and erection tolerances. The foundation must have
sufficient "footprint" to carry the weight of columns, beam
modules, and cars; sufficient transverse moment-resisting
capability to account for lateral loads due to winds, earthquakes,
and centrifugal forces in curves; and sufficient longitudinal
moment-resisting capability to allow for earthquakes as well as
forces arising from starting and stopping the trains. This last
consideration is greatly relieved by the beam-to-beam longitudinal
restraint, previously discussed, inasmuch as this permits
distributing the longitudinal braking forces of a multi-car train
among perhaps six columns instead of only one or two columns.
In a preferred arrangement, a concrete fender is placed around the
base of the column to prevent tampering with the adjustments, to
protect the columns from errant automobiles and trucks, and to
enhance the appearance of the assembly. These concrete fenders can
be pre-cast in halves for easy installation or replacement, and can
incorporate provisions for plants or other landscaping aids.
When the guideway curves as much as 60.degree. or thereabout in a
relatively short distance, loading per unit length on the beam
modules, columns, and foundations increases to such an extent that
the module length and consequent spacing between the columns and
foundations should be shortened by perhaps one-third. In such
situations, it is desirable to rotate the entire beam section,
giving the equivalent of superelevation as it is known in
conventional railways. In this connection the cross-head of the
column is normally inclined according to the desired angle of
superelevation; the upright element of the column may be inclined
or not depending on such considerations as appearance and available
space. For tight curves, the typical expansion joints between beam
modules may be eliminated at some or all junctions because moderate
flexing of the upright elements of the columns will absorb the
slight shifts in the elevated guideway.
Now referring to the drawings, first more particularly to FIGS.
1-4, an elevated railway system of this invention is illustrated as
comprising a beam or grider 1 supported at spaced intervals along
its length and having a first track T1 extending longitudinally
thereof at one side and a second track T2 corresponding to the
first track extending longitudinally thereof at the other side.
Cars such as indicated at C are adapted to travel on the tracks in
paths along the respective sides of the beam. Each track comprises
a lower rail R.sub.1 and an upper rail R.sub.2. The car has lower
wheels 3 traveling on the head 5 of the lower rail R.sub.1 and
tension means indicated generally at 7 extending laterally from the
car to the upper rail R.sub.2 and having a traveling
tension-transferring interconnection at 9 with the head 11 of the
upper rail for holding the car upright. The heads of the rails of
each track are in a plane inclined to the longitudinal vertical
plane of the beam with substantially all of the beam below said
inclined plane. Thus, the first track T.sub.1 comprises the lower
rail R.sub.1 and the upper rail R.sub.2 (first and second rails) at
one side of the beam with their heads in an inclined plane, and the
second track comprises the lower rail R.sub.1 and upper rail
R.sub.2 (third and fourth rails) at the other side of the beam
symmetrically opposite the first and second rails, the heads of the
third and fourth rails lying in a second plane inclined oppositely
to the first plane with substantially all of the beam below said
second plane.
More particularly, the beam 1, in transverse cross section, is
generally in the form of a hollow triangle (see particularly FIG.
4) having a base indicated at 13 and opposite sides 15 converging
toward one another in upward direction from the ends of the base to
an apex at A. The two lower rails R.sub.1 extend longitudinally of
the beam at the ends of the base B, i.e., at the lower corners of
the triangle, each arranged with the wheel-engageable outer surface
5a of its head 5 spaced outwardly from the respective side of the
beam and inclined downwardly in outward direction with respect to
the beam. The upper rails R.sub.2 extend longitudinally of the beam
at the apex A of the triangle, and extend laterally outwardly in
opposite directions from the apex with the inside surfaces 11a of
their head 11 facing inwardly with respect to the beam.
The lower rails R.sub.1 constitute lower chord members for the beam
stressed in tension under the dead load of the beam and the live
load of cars traveling along the beam. The upper rails R.sub.2
constitute upper chord members for the beam stressed in compression
under said dead and live loads. The beam also comprises bottom web
means at its base 13 between the two lower rails R.sub.1 and side
web means at its sides 15 between the lower rails and the apex A.
The web means takes dead and live load shear strains and asymmetric
live load torsional strains.
More particularly, the beam 1 for a continuous length of the system
comprises a plurality of basic beam or girder modules each
designated 1A in FIG. 1, each of these basic modules being suitably
supported at its ends at the requisite elevation on suitable
standards or pylons 17 (which may be of steel or concrete
construction) having T-heads 19 for bearing engagement by the base
13 of the module at its ends. Each module may have a length of 20
meters and each pylon may be 4.5 meters high, for example.
In greater detail, the lower rails R.sub.1 of each module 1A are
identical, each being a standard railroad rail (e.g., a 90 lb.
rail) having a flange or base 21, a web 23 and a head 5 (see FIG.
5), the outside surface 5a of the head constituting the
wheel-engageable surface of the rail. The lower rails are secured
together by the base or bottom web means 13 in spaced-apart
parallel relation, this web means including crossbars such as
indicated at 25 in FIG. 5, which are preferably tubular bars of
rectangular cross section, with the webs of the rails inclined
upwardly and outwardly as appears in FIGS. 3-5 from the ends of the
crossbars, preferably at an angle of generally 60.degree. to the
horizontal as indicated. The crossbars are cut away at each end as
shown in FIG. 5 to engage the flange 21 of the rail R.sub.1, the
crossbars and rails R.sub.1 being suitably welded together. The
upper rails R.sub.2 of each module are identical, each having a
flange or base 27, a web 29 and the head 11. The upper rails may be
of approximately the same weight per yard (e.g., 90 lb.) as the
lower rails. The upper rails of each module are mounted in
back-to-back spaced relation on a cylindrical tubular supplemental
upper chord member 33 constituted by a steel pipe extending the
full length of the module, with one edge of the flange of each rail
bearing on and welded at 35 to the top of the pipe and with the
flanges 27 extending vertically upward from member 33. Pipe 33 may
serve as a conduit for an electric power bus 38 for the system. The
webs 29 of the rails R.sub.2 extend generally horizontally, as
shown. Each upper rail has the two inwardly facing tracking
surfaces 11a on the inside of the rail head 11, these two surfaces
being angled relatively to one another as shown in FIG. 6, with the
upper surface 11a inclined upwardly and outwardly at a small angle,
e.g., 5.degree., off vertical, and the lower surface 11a inclined
downwardly and outwardly at a somewhat larger angle, e.g.,
15.degree., off vertical. A guard or cover 43 for the upper rails
is mounted on the upper edges of their flanges 27. The web 29 of
each upper rail R.sub.2 carries on its bottom a third rail 45 for
supplying electric power to the cars, this third rail being
insulated from the web as indicated at 47 in FIG. 6, and suitably
connected to the bus 38 at periodic intervals along the track.
The webs at sides 15 of each module 1A are constituted by plates
which may have openings or portholes 49 therein at intervals along
their length. These web plates 15 extend throughout the length of
the module, each having its lower edge 51 received in the inside
corner of the respective lower rail R.sub.1 at the juncture of its
web and flange (see FIG. 5) and being suitably welded to the lower
rail. Each side plate 15 angles upwardly and inwardly from the
respective lower rail and has its upper edge engaging the
respective side of the pipe 33 and welded thereto as indicated at
53 in FIG. 6. The base or bottom web 13 comprises a bottom plate
55, which may correspond to side plates 15, welded to the bottom of
the crossbars, this bottom plate 55 extending throughout the length
of the module. The bottom plate may have grilles 49a in its
portholes 49. Rails 57 providing a service track for a service
vehicle may be mounted on the crossbars 25 extending throughout the
length of the module. While the side webs 15 are shown as plates
having the holes 49 therein, and the bottom web 13 is shown as
comprising plate 55, it will be understood that these webs may be
of other structural form, e.g., trusses, and the term `web` is
intended to cover this.
The car C comprises a frame having inboard and outboard sections
("inboard" being toward the beam and "outboard" being away from the
beam), the inboard section being indicated at 59 in FIG. 7, with a
floor 61 extending between these sections, and an enclosing shell
63. A preferred interior arrangement for the car is shown in FIG.
3. Generally, the car will have two lower wheels such as indicated
at 3 in FIG. 7 on its inboard side adjacent its ends (one wheel
ahead of and the other behind the center of the car). Each of these
lower wheels 65 is on an axle 67 journalled in bearings 69 in a
truck 71 pivoted on a pin 73 extending horizontally on the inboard
side of the car at about midheight of the car. Each truck 71 and
wheel 65 carried thereby is accommodated in a recess 75 in the
inboard side of the car. The truck is preferably mounted for some
degree of damped vertical freedom, as by means of upper and lower
links 78 and 79, with a conventional air/oil shock absorber 80
functioning as a damper (and which may also be a load leveler). The
truck is generally positioned so that the plane of the wheel 3 is
in the inclined plane of the web 23 of the respective lower rail
R.sub.1, each lower wheel thereby bearing properly on the head of
the respective lower rail R.sub.1. The lower wheels 3 are
preferably steel-rimmed and double-flanged positively to engage the
head of the rail. The truck for at least one of the lower wheels
carries a drive module M comprising an electric motor drive
including an output shaft 81 geared at 83 to the lower wheel. The
drive module may also include suitable braking means for the wheel.
The truck 71 may include hooks such as indicated at 85 extending
under the head of the lower rail R.sub.1 to hold the wheel against
rising off the rail.
Each car carries a tension means or outrigger 7 above each of its
lower wheels 3, the tension vector being indicated at TV in FIG. 4.
Also illustrated in FIG. 4 are the gravity vector GV of the weight
of the car and the vector WV of the weight of the car on the lower
wheels. The tension-transferring interconnection 9 of each
outrigger 7 comprises an upper series W.sub.1 of rollers W which
engage the upper tracking surface 11a of the respective upper rail
R.sub.2 and a lower series W.sub.2 of rollers W which engage the
lower tracking surface 11a of the respective upper rail. Each
series of rollers is carried by an I-beam 87, the web 89 of this
beam being slotted as indicated at 91 in FIG. 9 with the rollers
mounted on shafts 93 journalled in the flanges 95 of the I-beam and
accommodated in the slots 91. The two I-beams (carrying the two
series of wheels) are mounted in back-to-back relation inclined to
each other at an angle corresponding to the angle between the
planes of the two upper and lower tracking bearing surfaces 11a of
an upper rail R.sub.2 (e.g., 20.degree.) on an elongate truck 97.
The latter has a portion 99 of generally C-shape in cross section
which freely straddles the head 31 of the respective upper rail,
and which has upper and lower lugs 101 and 103 above and below the
web of the respective upper rail to which the I-beams are secured.
The lugs extend into slots 91 in the webs of the I-beams, and the
I-beams are secured to the ends of the lugs via pins 105 extending
between the flanges 95 of the I-beams. Three sets of lugs and pins
are shown for each I-beam, and the holes for the central pins of
the three may be slightly oversize for limited flexing of the
I-beams. The truck 97 has an endwise extension 107 from its
C-section portion carrying a power pickup 109 for engagement with
the third rail 45.
The truck 97 carrying the upper rollers W is mounted for
up-and-down movement and in-and-out movement relative to the car C
by means indicated generally at 111 in FIG. 8 comprising a carriage
113 having rollers 115 at its ends adapted to roll up and down in
arcuate channel section tracks 117 mounted on members 119 of the
inboard section of the car frame at the fore and aft ends of the
recess 75 in the inboard side of the car. These tracks are curved
on an arc centered in an axis 123 (see FIG. 7) which generally
coincides with the junction of vectors GV, TV, and WV in FIG. 4.
The truck 97 is mounted on the carriage for movement in and out
relative to the carriage (laterally relative to the car) by means
comprising a drag link 125 and a hydraulic equalizer cylinder 127.
The link 125 is pin-connected at one end as indicated at 129 to the
end of the carriage 113 toward the respective end of the car and at
its other end as indicated at 131 to the truck in such manner as to
permit inward and outward movement of the truck relative to the
carriage. The cylinder has one end pin-connected at 133 to the
carriage and has its piston rod 135 extending from piston 137
therein pin-connected at 139 to the truck. The inner end of the
cylinder is vented and the outer end is adapted to be supplied with
hydraulic fluid at relatively high pressure (e.g., 1800 psi). The
pressure ends (the outer ends) of the cylinders for the fore and
aft upper wheel sets are interconnected by an equalizer line 141
for anti-twist compensation.
Unconventional transit systems have always encountered great
difficulty for lack of a practical switch, particularly one that is
suitable for two-way traffic. To permit discussion of this subject,
it is appropriate to establish a convention to identify the several
lines. As shown in FIGS. 11 and 11A, C indicates the common line
where cars normally approach a branch or point of divergence. After
divergence, one line is identified as A and the other B. In the
reverse direction, where branch lines converge, the same letters
are used with a "prime". Thus, there are six different tracks and
12 different rails involved in the situation shown in FIGS. 11,
11A, 12 and 12A.
Conventional duo-rail systems manage switching by keeping all rails
in a common (essentially horizontal) plane. Only the flanges of the
car wheels penetrate this plane. The result is practical, if not
absolutely safe; there have been occasional head-on collisions
between opposing traffic, and the safety precautions to avoid such
collision are expensive and time-consuming. No unconventional
transit system has approached the degree of safety and practicality
of duo-rail switches, particularly where two-way traffic is needed.
It appears that unconventional systems encounter switching trouble
because their cars occupy much more of that vertical regime
occupied by the tracks than is true for duo-rail systems, where
nothing more than wheel flanges extend below the top of the rails.
Consequently, the movable part of the switch must move much farther
laterally (and is more difficult to support mechanically) than is
true for duo-rail.
Many current unconventional systems employ a "passive" switch in
which the guideway is U-shaped and the car hugs either the left or
right wall of the U when it passes through a switch. This can be
expected to succeed reasonably well for one-way traffic, but, when
it is attempted to do the same thing for two-way traffic, the
occupation of the same vertical regime by the wall and much of the
vehicle creates an almost insurmountable problem.
This invention involves a switch which is believed to solve these
problems, avoiding some of the disadvantages of dual duo-rail
switches in the process. In the interest of compactness, it takes
advantage of the superior hill-climbing capability of the
suspension arrangement previously discussed.
The underlying concept in this switch is threefold. First, the
various tracks for the C-A-B combination should be kept coplanar
until they have separated sufficiently to go their own way. Second,
there is no need to keep the various tracks of the C'-A'-B'
combination in the same plane as the C-A-B group; in fact, it is
advantageous if they do not. Third, penetrations by the car into
the switch plane should be few and local in order to keep
mechanical motions small and simple.
The two rails R.sub.1 and R.sub.2 to which a car of the present
invention attaches are in a plane that slopes 60.degree. to the
horizontal, for example. The switch concept of this invention is to
keep all rails of the C-A-B combination in this same sloping plane,
and to do likewise with the C'-A'-B' group. To facilitate further
discussion, an additional convention will be adopted: "A" will be
defined as the branch that is higher, and "B" the lower. It will be
seen that the A line may continue straight ahead, or turn left or
right, as the situation demands; the same is true of the B
line.
A switching system of this invention for lines C--C', A--A' and
B--B' is illustrated in FIGS. 11, 11A, 12, 12A and 13-16. Lines
C--C' are constituted by the tracks T.sub.1 and T.sub.2 on opposite
sides of a first beam 1CC'. Lines A--A' are constituted by the
tracks T.sub.1 and T.sub.2 on opposite sides of a second beam 1AA',
and lines B--B' are constituted by the tracks on opposite sides of
a third beam 1BB'. As shown, beams 1CC' and 1BB' in effect
constitute a continuous double-track straight line and beam 1AA'
constitutes a double-track branch line curving away from the 1CC' -
1BB' combination. It will be understood, however, that beam 1BB'
may be a double-track branch line curving away from beam 1CC'
oppositely to beam 1AA'. The tracks T.sub.1 and T.sub.2 of all of
the beams are generally at the same angle of inclination as
heretofore described (e.g., 60.degree. to the horizontal). At
SW.sub.1 is indicated a first means for switching cars between line
C (the first track T.sub.1 of beam 1CC') and line B (the first
track T.sub.1 of beam 1BB') or line A (the first Track T.sub.1 of
beam 1AA'), and at SW.sub.2 is indicated a second means for
switching cars between line C' (the second track T.sub.2 of beam
1CC') and line B' (the second track T.sub.2 of beam 1BB') or line
A' (the second track T.sub.2 of beam 1AA'). The switching means
SW.sub.1 comprises a descending track section 151 and an ascending
track section 153 having a crossover at 155, with a movable track
section 157 between line C (the first track T.sub.1 of beam 1CC')
and the respective descending and ascending track sections 153 and
155. The switching means SW.sub.2 is identical to the means
SW.sub.1 (but for lines C'-B'-A'). The descending and ascending
track sections 153 and 155, in any vertical transverse plane along
their length, are generally at the same inclination as the tracks
of the beams and, in vertical transverse planes progressively from
beam 1CC' to the crossover 155, are on the sides of triangles of
progressively increasing size, as illustrated in FIGS. 13-16.
Beam 1CC' (with lines CC' at opposite sides thereof) in effect
terminates at a station S.sub.1. FIG. 13 shows the cross section at
station 13, corresponding to the standard beam cross section
illustrated in FIG. 2. Between station S.sub.1 and the movable
track section 157 is a relatively short generally horizontal
extension 159 of beam 1CC' of progressively increasing, generally
triangular cross section from station S.sub.1 to its end at a
station designated S.sub.2. Tracks T.sub.1 and T.sub.2 at opposite
sides of extension 159 diverge gradually away from one another, as
viewed in plan in FIG. 11, from station S.sub.1 to station S.sub.2,
but remain generally horizontal as viewed in elevation in FIG. 12.
The movable track sections 157 of the switching means SW.sub.1 and
SW.sub.2 lie on the sides of a beam 161 extending from station
S.sub.2 to a station designated S.sub.3, this beam being of
progressively increasing, generally triangular cross section from
station S.sub.2 to S.sub.3. The crossover 155 is at a station
designated S.sub.4. The descending and ascending track sections 151
and 153 of the switching means SW.sub.1 and SW.sub.2 lie on the
sides of a beam 163 extending from station S.sub.3 to a station
designated S.sub.5, this beam being of progressively increasing,
generally triangular cross section from station S.sub.3 to station
S.sub.5. At station S.sub.5, lines B and B' are spaced apart
relative to one another in plan, and lines A and A' lie
side-by-side between lines B and B' as viewed in FIG. 11, and lines
A and A' lie above lines B and B' as viewed in FIG. 12. Beyond
station S.sub.5, line B' passes under lines A and A' and lines B
and B' converge toward one another, resuming their normal
relationship on opposite sides of beam 1BB' at a station S.sub.6
(see FIG. 12A). Lines A and A' are in their normal side-by-side
relationship at station S.sub.5 and are shown as curving away from
lines B and B' on a curved beam 1AA' (see FIG. 11A).
The result, then, is a compact and practical switch arrangement for
two-way traffic with an advantage not achieved even in dual
duo-rail switches; namely, cars of the opposing lines never occupy
the same point in space, so that (1) head-on collisions are
impossible; (2) there is no need to resort to time-sharing,
signalling and other precautions at this point; and (3)
traffic-carrying capacity on the two opposing lines is greatly
increased.
As noted above, an elevator may be provided in a car, with the
attendant advantages of avoiding the expense, visual impact, and
inflexibility associated with elevated stations. This is
particularly true for stations in neighborhood areas, where only a
few people may desire to get on or off a given train (a reasonable
assumption provided stations are not far apart and service is
frequent).
At ground-level stations, it is possible to place elevator shafts
on each side of the track (one shaft for each direction of
traffic), which shafts logically have vertical tracks to guide the
elevator cab, a retractable cover to keep out snow and thrown
objects, and doors at ground level to prevent unauthorized
entrance. Even though the shaft structure may be of glass or
transparent plastic, it may be visually objectionable. The shaft
may also be rather expensive and a maintenance problem, especially
if it is transparent.
An alternative is to use a novel guard means of this invention
which serves two main purposes: first, it assures that people and
pet animals cannot be injured by the descending elevator; and,
second, it gives limited guidance to the elevator as it
descends.
By straightforward mechanical design, the elevator can be suspended
and kept level by a combination of cables as the cab is lowered to
the ground or floor level, all of these cables and their associated
drives and brakes being part of the car and controlled by an
operator on the car. Redundancy in the cables, drives, and brakes
may assure adequate safety. The guard means is designed to occupy
the space that is needed for the descending elevator to keep people
out from under the descending elevator, and to surrender that space
in a safe manner as the elevator descends. The top of the guard
means also engages the bottom of the elevator to prevent the
elevator from swaying due to winds or other physical disturbances,
and in fact guides the descending elevator to align with a recess
in the station platform, so that the floor of the elevator will be
at platform level when passengers board and de-board.
In its most rugged anad elementary form, the guard means is a rigid
(possibily transparent) shell extending high enough above the
ground to preclude accidents and mischief about the top. It has a
pointed top to avoid the accumulation of snow (and other objects)
and also to facilitate engagement and alignment with a conical
recess in the bottom of the elevator. Beneath the shell is a recess
in the station platform or floor of appropriate cross section and
depth to receive the entire guard means shell. Also provided is a
spring mechanism to overcome the weight of the shell and thus cause
it to be "up" except when forced down by the weight of the
elevator. This spring mechanism can be refined to offset a large
fraction of the elevator's empty weight, thereby saving energy
demands in the elevator drive mechanism. It may also include an
accompanying damper to keep the elevator from descending too fast,
and possibly a remote-controlled brake to stop the elevator's
descent in the event of certain mechanical failures aboard the car.
Finally, the mechanism can be retracted or extended by remote
control to inform travelers at a glance whether the transit system,
or at least a particular station, is operating.
In places where vandalism is not serious, it is possible to reduce
the depth of the hole in the platform and improve the appearance of
the guard means as shown in FIG. 17. This embodiment would have the
same hard, pointed top as the basic shell already discussed; it
would also have substantially the same springs, dampers, and other
functional options as discussed there. The essential difference
would be a pliable rather than a rigid sidewall for the shell,
which sidewall would telescope or otherwise collapse (e.g., in
accordion manner) as the elevator descends. By giving the shell
suitable flexibility and with suitable control of escaping air (as
by controlled porosity of the shell fabric), the shell can be
caused to swell as it is compressed from above, thereby assuring
that the necked-down profile of the shell does not permit people or
pets to enter the forbidden zone as the elevator descends.
In FIG. 17, the beam is again indicated at 1 and a car at C. The
elevator is indicated at 171 (see also (FIG. 3) and is shown as
having a conical recess 173 in its bottom. Any suitable mechanism
may be provided for raising and lowering the elevator. FIG. 17
illustrates two guard means M.sub.1 and M.sub.2 at a station 175
for cars on the two tracks T.sub.1 and T.sub.2 of the beam 1. Each
of these is illustrated as of the collapsible sidewall type (e.g.,
adapted to collapse in accordion manner). Suitable spring means
(not shown) is provided inside each guard means normally to extend
it to its raised extended position as shown for guard means M.sub.1
in FIG. 17. When so extended, the guard means is of sufficient
height to exclude people from the area under a descending elevator
at the station 175. Each guard means has a conical top 177 serving
in conjunction with recess 173 in the bottom of the elevator 171 as
interengageable alignment means for the purpose above described. A
car C is stopped at the station 175 with the elevator above the
respective guard means M.sub.1 and M.sub.2, and the elevator then
descends for ingress and egress of passengers. As it descends, it
engages the top of the guard means and pushes it downwardly into a
recess 179 in the floor or platform 181 of the station, as shown
for the guard means M.sub.2. When the elevator ascends, the guard
means moves back up to its raised position.
Thermal expansion between successive beam modules may cause a gap
approaching 20 mm. It is desirable that the beam modules be placed
and interconnected so as to minimize wear and tear on rollers of
the outrigger in this situation. It follows, then, that the maximum
gap at the lower rails must exceed that of the top rails by
whatever amount is allowed for tolerances in fabrication of the
beams, otherwise tailoring of the beam modules would be required in
the field. Furthermore, as a practical matter, it is important to
be able to use straight beam modules in situations where the
guideway alignment demands extremely gentle curvature (which may be
vertical as well as horizontal). This consideration adds further to
the gap at the lower rails, if the upper-rail gap is to be kept at
a minimum. In fact, the nominally straight beam modules must be
made with both lower rails slightly fore-shortened in order to
permit lateral and/or downward curves without trimming in the
field.
Preliminary studies indicate that it is both desirable and feasible
to permit a combined allowance of .+-.25 mm. for such tolerances
and alignment provisions, in addition to an allowance of some 18
mm. for expansion. This must be done by inserting some sort of
bridge means between the two beam modules. This bridge means must
satisfy several additional requirements:
a. The assembly should also allow for vertical and lateral
misalignment from one lower rail to the next. (Some misalignment is
inevitable inasmuch as the upper rails and both lower rails are
integral parts of the beam module, without adjustment
provision.)
b. It must carry the design rolling loads with allowance for impact
and fatigue, and without significant deflection.
c. It must carry moderate lateral loads, to allow for winds and
other contigencies.
d. It must be securely attached longitudinally in order to transfer
acceleration and braking forces to the main guideway structure.
e. It should not have excessive gaps re the rolling wheel, or as
viewed by operators, passengers, and pedestrians on the ground.
f. It should, if at all practical, present suitable surfaces and
have adequate strength to resist the same emergency loads for which
the car's safety hooks are designed.
g. Any relatively complex mechanism, if needed, should be on a
removable part rather than on the beam modules to provide for
correction of developing defects and/or improvement of the design
from time to time.
h. The construction should avoid loose fits of separate parts
(which would inevitably mean objectionable noise) and should
minimize cavities in the upper surface that can accumulate litter
and possibly foul the operation.
i. If the assembly is unable to break accumulated ice, it must
provide for active heaters.
j. The parts should be economical to fabricate, install, inspect,
maintain, and replace--to the extent practical while satisfying the
other requirements. Studies strongly suggest that there is no
feasible solution to this problem which would permit a single
"bridge" structure to satisfy the entire range of variation, which
is some 43 mm. The present solution is to have a family of similar
bridge members, each of which provides the 18 mm. expansion
allowance and a portion (in this case one-fourth) of the remaining
allowance for tolerances and gentle curvature.
FIGS. 18-24 illustrate a solution by this invention of the
expansion joint problem. This involves a pair of identical members
(which may be referred to as blades) which fit together in
hermaphrodite manner (each member having both male and female
elements) to resist bending in the lateral, downward, and upward
directions. Their combined upper portions, in cross section, are
the profile of a standard railhead to provide rolling support and
guidance to the wheel of a car; and also to clear (or engage with)
the safety hooks of the car. Their lower portion is a foreshortened
substitute for a conventional rail, in order to permit the pair of
blades to transmit vertical, lateral, and even torsional loads into
the adjacent beams. Connection to the beam module is at the rail
itself, to minimize tolerance accumulations and take advantage of
the bulk/strength residing there and the connection is such as to
permit slight rotation in the plane of the rail web. Lateral-load
transfer to the beam modules is by direct engagement between a male
lug of the blade and a female slot machined into the railhead.
Rotational loads can be resisted by engagement with the walls of
this slot, together with lateral load transfer at a lower key,
which will be discussed further. Rolling loads, i.e., loads
parallel to the rail web, are conducted directly into the web via
the same key.
The blades, together, accomplish a telescoping action to satisfy
the intended variation of some 30 mm. Thus, one blade attaches to a
first beam module and the second blade attaches to the second beam
module. Construction of the blades would be simpler if the lugs
were offset from the center of the rail, but the attendant
torsional loads and unsymmetrical loading makes this appear
unattractive. Further, it is mechanically advantageous to enlarge
the section of each blade as its lug end is approached. Finally,
the beam-to-blade gap implicit in this solution is objectionable
from a structural and/or visiual standpoint. Therefore, the
preferred solution has a lug that is essentially centered and an
internal design to give continuity of back-up structure behind this
lug.
Each blade has a multiplicity of mating lugs and slots in its lower
area to transfer both upward (hook) and downward (wheel) loads in
the order of 5 KG. These must be long enough, in concert, to
preserve adequate engagement with each other through the full range
of adjustment and must have sufficient strength/bearing area to
carry the greatest transfer loads, which are found to exist when
the pair of blades are extended to the maximum.
Lateral loads are arbitrary, pending results of actual experience
with the system. It is assumed that rolling loads from the wheel
profile can cause some tendency to separate laterally at the rail
surface; accordingly, the main provision for lateral engagement
between the blades is located near the upper surface. Thus the
present solution has a "hook" that extends laterally and then
downward from each blade near its lug end (again contributing to
the build-up of cross-sectional area at the lug end). The opposite
end of the blade has material cut away to receive the hook of its
twin. Details of the hook and recess have been selected after
consideration of methods for machining one part, assembling a pair
together, and operational failure modes.
The preferred arrangement is shown to have the blade extend over
the entire width of the railhead at its lug end. This seems
particularly desirable from the standpoint of appearance and noise
(as abrupt changes in support to the wheel are minimized), even
though it may be somewhat more difficult to machine than
alternatives. The portion of the rail-surface gap that is closer to
the centerline of the rail may be either rectangular (again
favoring convenience of machining) or parallelogram in nature; if
it is rectangular, it follows that there are two identical
rectangular gaps in staggered relationship on opposite sides of the
rail centerline.
It is contemplated that four sets of the blades may be needed to
make up the entire family. The first set satisfies hot-day rail
gaps 2 mm. to 14 mm.; the second, 14 to 27 mm.; the third 27 to 39
mm.; and the fourth, 39 to 52 mm. Inasmuch as 52 mm. exceeds 2 mm.
by the desired 50 mm., the requirement of .+-. 25 mm. (apart from
temperature variation) is therefore satisfied. The several lengths
involved are seen to lend themselves to virtually the same forging
and (automatic) machining techniques.
To preclude rattles and supplement transverse clamping betwen the
two blades, the construction includes a spring-steel clamp that
grips the lower extremity of the blades. The clamp is slidable
relative to at least one of the two blades, and must not work along
to an undesired longitudinal position. The present solution calls
for pinning the clamp to one of the two blades, with a pin that is
easily engaged, disengaged, and inspected.
In regions where accumulate ice is a significant problem, the clamp
may incorporate an electrical heater. Heat is conducted through the
clamping interface into the pair of blades, to preclude ice
deposit.
To prevent the blade from lifting, a cross-pin engages with the
projection of the main railhead on both sides of the blade lug. The
key, previously mentioned, also serves to transfer longitudinal
loads between the main rail and the corresponding blade, to cause
the blades to telescope as desired. The rail cutaway needed for
this joint is shown in FIG. 19; it provides a slotted projection of
the railhead for the blade lugs, a locally machined lower surface
of the railhead to engage with the cross-pin, a recess for the key,
etc. The foot of the rail and as much as practical of the web
extend underneath the expansion joint blades almost to the center
of the overall joint, in order that the beam-end and its associated
structure will be near that of the adjacent beam. This is desirable
mainly because the two beam modules bear on a common column,
transferring their load through a common mount. All beam modules
whether curved or straight, may have this same cutaway in the
interest of interchangeability and replaceability.
The objectives are thus satisfied. A crucial point is that a
single, blunt rail-surface gap of some 30 mm., which would almost
surely be to noisy even if mechanically sound, is avoided by
substituting a parallelogram-shaped gap that affords support to 50%
or more of the wheel profile at any given wheel position or,
alternatively, subdividing the gap into several small gaps in a
staggered arrangement to achieve the same result.
Referring to FIGS. 18-24, there is indicated at 201 an expansion
joint of this invention positioned in the gap 203 between the ends
of two rails R of a track of the railway system of the invention.
The beam modules 1A are mounted on the columns or pylons 17 with
appropriate gaps 203 between the ends of the rails R on the beam
modules. As shown in FIG. 19, each rail R has a portion of its head
5 and its webs 23 cut away as indicated at 205, so that its base or
flange 21 and a part 207 of its web project beyond the end of the
rail head 5. Also, a portion of the end of the web 23 of the rail
is cut away under the end portion of the rail head so as to provide
a recess 209 in the end of the web under the end portion of the
rail head. The upper edge of the projecting portion 207 of the rail
web 23 resulting from the cutaway 205 slopes down from the lower
edge of the recess as shown in FIG. 19. which
The expansion joint 201 comprises an end extension or blade member
211 for one of the two rails R shown in FIGS. 18 and 19, and an end
extension or blade member 213 for the other of these two rails each
extension being secured at one end to the end of the respective
rail and extending across the gap toward the end of the other rail.
The two extensions 211 and 213 are generally identical, each
comprising a web or blade 215 with an inside face 217 in sliding
engagement with the web or blade 215 of the other extension and a
head 218 on the web. The webs or blades 215 of the two extensions
211 and 213 are generally aligned with and extend between the ends
of the webs 23 of the two rails R, overlying the projecting parts
207 in the rail webs (and the projecting parts of the rail flanges
21). Each web 215 has a laterally offset tongue 219 at its rail end
received in a notch 221 in the projecting end of the respective
railhead 5 with a sliding fit, and extending down into the recess
209. Each extension (211, 213) is pivotally mounted at its rail end
on the end of the respective rail R for pivoting on an axis
transverse to the rail by means of a key 222 pivotally mounted in a
semicircular recess 223 at the lower edge of the recess 209, the
tongue 219 at its lower edge interfitting with this key as
indicated at 225. The tongue 219 is held against upward movement
off the key 222 by means of a stop 227 constituted by a pin pressed
in a hole 229 in the tongue underlying the projecting end of the
railhead 5.
The webs 215 of the extensions 211, 213 have slidably interengaged
longitudinal tongue and groove interconnections at their inside
faces 217 for transmission of rolling and derailment loads (e.g.,
vertically, both up and down, as viewed in FIG. 19), the tongues
being indicated at 231 and the grooves at 233. These resist bending
of the extensions 211, 213 in the plane of the rails and are long
enough for this purpose in all degrees of expansion of the joint.
Also, the web 23 of each extension 211, 213 has a slidably
interengaged longitudinally extending tongue-and-groove
interconnection with the head 218 of the other extension for
transmission of lateral loads, the tongue being indicated at 235
and the groove 237. These resist lateral bending of the extensions
211, 213 in all degrees of expansion of the joint. The webs 215 of
the extensions have flanges 239 at their edges opposite their heads
218 (i.e., at their bottom edges) and means is provided for
clamping the webs 215 together while permitting relative sliding
movement thereof comprising a spring clamp 241 straddling the
flanges 239 and secured as by a pin 243 to one of the flanges. Each
of the extensions 211, 213 has the head 218 on its web 215 in
extension of the head of the respective rail R. The head 218 of
each extension extends from adjacent the end of the respective rail
toward but terminates short of the end of the other rail, and the
heads 218 of the two extensions have opposed angled ends 245 at an
expansion gap 247 therebetween. As shown, these angled ends 245 are
straight ends inclined to the plane of the rails forming a
parallelogrammatic gap 247.
To permit the key members to carry lateral loads, they are provided
with circular enlargements or heads at each end. These heads engage
the rail web 23 and the blade webs 219. To permit accurate matching
of the blade's height with that of the corresponding rail, the
upper surface of the key shank is made flat rather than
semicircular; this allows convenient grinding in the field. To
permit the keys to drive the respective blades in telescoping
fashion, the upper portion of each key head fits into and engages
with a semicircular recess in the web 219 of the blade.
In view of the above, it will be seen that the several objects of
the invention are achieved and other advantageous results
attained.
As various changes could be made in the above constructions without
departing from the scope of the invention, it is intended that all
matter contained in the above description or shown in the
accompanying drawings shall be interpreted as illustrative and not
in a limiting sense.
* * * * *