Note: Descriptions are shown in the official language in which they were submitted.
CA 02287734 1999-10-28
TITLE: AUXILIARY TRUCK FOR RAIL CAR
TECHNICAL FIELD
The invention is directed to an auxiliary truck for supporting a rail car by
cradling an
S inoperable wheel-axle set above and out of contact with the railway tracks
while the
attached loaded rail car is shunted on the tracks to a repair location.
BACKGROUND OF THE ART
Rail car wheel-axle sets, comprising two flanged wheels mounted on an axle,
are often
the cause of train breakdown. The wheel-axle sets are commonly combined in a
multiple axle rail car truck with journal bearings, and spring suspension. In
this
description and claims, the term "railcar" is used for convenience to refer to
and is
intended to include all rolling stock that can be supported on rails,
including for
example: locomotives, freight railcars of all types, passenger railcars, track
maintenance equipment, mass transit passenger cars and transit locomotives.
Railway locomotives are extremely heavy including diesel/electric engines and
power
transmission mounted on six axles or more. Since the axles are mechanically
powered, once a malfunction occurs, it is necessary to disengage the axles
from the
drive system to roll the locomotive to a repair site. However, if such a
disengagement
is not possible, due to the massive weight of the locomotives, high lift
capacity cranes
are required to lift the locomotive off the rails and place it on a dopey to
be
transported to a repair site. This type of operation involves significant
delay and
schedule disruption, is labour intensive, potentially dangerous and employs
equipment
that is expensive to acquire and to maintain in service.
Train breakdown involving malfunctioning locomotives or freight cars, can be
caused
by locking up of the wheel axle sets due to failure of power transmission, a
journal
bearing, or cracks which develop in the wheel or axle themselves, thereby
disabling
the railcar truck. Repair options include replacing the bearings and damaged
wheel
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axle set in location. However, this involves significant down time for the
entire train
and line upon which the train is resting. A preferred option is to shunt the
damaged
railcar to a siding and perform repairs in relative seclusion. Where suitable
equipment
is not available and the distance of shunting is short, operators feel obliged
to force
the damaged railcar by sliding the locked wheel set on the rail surfaces. This
type of
shunting is prone to damage the wheels and rails through abrasion.
A preferred method of shunting a railcar for repair has been to raise the
locked axle set
with portable jacks so as to disengage the wheel from the railhead upon which
it has
been resting. When sufficient clearance is available, auxiliary trucks or
skates are
inserted under the wheel and the axle is lowered to rest on the auxiliary
truck above
and out of engagement with the tracks.
Disadvantages with existing auxiliary trucks are several. The weight capacity
of
1 S conventional trucks is usually quite low and they are used extensively in
repair sheds
and assembly operations where the truck itself or a wheel axle assembly only
is being
transferred about. Where a fully loaded railcar is to be moved with such a
device, the
weight carrying capacity leads to a design with such heavy components that it
becomes impractical to transport such auxiliary trucks over the rough terrain
adjacent
rail tracks with human effort. Where a light capacity truck would weigh 500
pounds
or less, a higher capacity auxiliary truck is of a weight well beyond the
capacity of
two workmen to conveniently carry to the site of the damaged wheel set. If
lifting
machinery or transport carriers are required to carry an auxiliary truck, it
becomes
impractical. If transport of heavy equipment is required, the auxiliary trucks
cannot
be used by train crews at remote locations and the application of such
auxiliary trucks
would be restricted to areas in close proximity to repair locations or heavy
equipment
depots.
For example, United States Patent No. 2,919,659 to Grimany discloses a skate
for
moving railroad equipment which comprises two parallel plates clamped together
with
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a pair of end roller wheels between the parallel plates. In order to provide
lateral
stability, the damaged wheel of the railcar is clamped with bolts between the
parallel
plates of the skate. The disadvantage of the Grimany skate is that it is
difficult to
carry such a heavy one-piece device and if a locomotive or fully loaded
railcar is to be
supported, the structural requirements of such a skate would increase the
weight of
members to such an extent that it would be impractical for one or two members
of a
typical rail crew to manually carry the device to a repair location on the
train. In
addition, lateral stability of the skate is questionable and the operator is
required to
tighten bolts to clamp the wheel between the parallel plates of the skate. The
requirement for tools and heavy lifting severely limits the application of
such a
device.
Lateral stability is provided by the emergency carriage described in United
States
Patent No. 1,206,994 to Craigmile. The provision of a top beam to tie the top
of the
wheel together involves further effort, however, the tying together of
parallel skates
on the parallel rails with a channel beam represents an improvement over the
above
described device. The skates are assembled as a complete unit and therefore,
the
Craigmile device suffers from the same disadvantage that if a skate is to be
designed
to carry the extremely high weights of a locomotive or loaded railcar, the
weight of
the skate would exceed practical lifting capabilities of two persons. In
practice, the
Craigmile type of emergency carriage would be restricted to use for unloaded
railcars
or components of railway trucks. United States Patent 2,491,034 to Couch and
U.S.
Patent 811,965 to Smith show alternative wheel supporting trucks with the same
disadvantages.
An object of the present invention is to provide an auxiliary truck for
railcars, which
can be transported to the required location by members of the train crew
carrying the
components over relatively rough terrain.
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Another object of the invention is to provide a auxiliary truck which can be
installed
and used without requiring tools.
A further object of the invention is to provide an auxiliary truck capable of
carrying
75 tons or more weight capacity for use in association with a locomotive or a
fully
loaded railcar thereby enabling extremely heavy locomotives to be moved
without
cranes and avoiding the necessity of unloading a loaded railcar prior to
shunting.
DISCLOSURE OF THE INVENTION
The invention provides a novel auxiliary truck for supporting a rail car wheel-
axle set
above and out of contact with parallel rail tracks, to enable a rail car with
inoperative
wheels to be shunted along the tracks to a repair location. The auxiliary
truck is
quickly assembled from components that weigh under 90 pounds to facilitate
manual
carrying and are assembled together without tools.
The auxiliary truck is capable of carrying the high loads of the middle axles
of a
locomotive at an elevation above the track such that the remaining locomotive
wheels
remain on the track and the supported axle is raised about 2 inches so that
the
suspension can accommodate the vertical displacement of the supported axle
without
damage. The low profile and high capacity of the auxiliary truck permit this
application which has to date not been possible with conventional skates or
dolleys.
The auxiliary truck has uses in manufacturing plants or warehouses where box
cars
are often pushed into an enclosed building against a stop bumper. The trucks
under
the box car can be disengaged on excessive impact. The invention provides a
simple
means for removing the damaged boxcar from within an enclosed space where
cranes
and other large equipment cannot gain access.
The auxiliary truck has two parallel truck wheel axle assemblies, upon which
are
mounted two rail car wheel support assemblies. Each axle assembly includes two
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truck wheels centrally mounted on stub axles, and each stub axle is releasably
secured
into a transverse tubular brace.
The support assemblies are built up of a pair of parallel elongate plates,
with one truck
wheel from each of the two axle assemblies disposed between. Each plate
includes a
stub axle cradle for releasably journalling the stub axles. Two shoulder pins
releasably connect a central portion of each parallel plate pair together
spaced apart a
selected distance.
The stub axle cradle preferably forms a semicylindrical recess disposed at
lower front
and rear corners of each plate with an open mouth inclined at an acute angle
relative
to horizontal. The acute angle orientation of the mouth has the following
benefits.
During assembly, the plates are first mounted to one axle assembly then
rotated into
engagement with the other axle assembly. The acute angle opening guilds the
components into engagement as the plates rotate toward the axle assembly.
During
disassembly, the acute angle opening likewise eases disengagement without
requiring
use of pry bars or tools.
There is no need to physically attach the stub axles to the plates with bolts
or other
connectors. The heavy weight of the rail car maintains engagement between the
stub
axles and plates. The stub axles include circumferential ridges to laterally
restrain the
plates. As a result, time and labour involved in assembling the truck is
minimized and
no tools are required for the operation.
Although the carrying capacity of the assembled truck is over 75 tons, the
individual
components of the truck all weight under 90 pounds and can be easily carried
by
members of the train crew to the site of the inoperative axle or wheel. No
tools are
required since the components are secured with pins and snap rings that are
quickly
removed and replaced by hand.
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The simple design of components lowers cost to the extent that it is practical
to
include such a truck as standard equipment for each train. In contrast,
conventional
trucks either have a carrying capacity that is too low to support a loaded
rail car, or
conventional trucks are too heavy to be easily carried long distances by train
crews.
Further details of the invention and its advantages will be apparent from the
detailed
description and drawings included below.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be readily understood, a preferred embodiments
of the
invention will be described by way of example, with reference to the
accompanying
drawings wherein:
Figure 1 is a perspective view of the assembled auxiliary truck with two
parallel axle assemblies, and two rail car wheel support assemblies mounted to
the
stub axles of the truck wheels;
Figure 2 is a horizontal sectional view of the assembled auxiliary truck
showing the interconnection of components;
Figure 3 is a side elevation view;
Figure 4 is a detail elevation view of one truck wheel and associated
components; and
Figure 5 is a side elevation view like Fig. 3 showing the rotation of the
plates
about one axle assembly to engage or disengage the other axle assembly, and in
particular showing the use of the acute angled recess to guide the stub axle
and semi-
cylindrical recess into engagement.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Figure 1 illustrates the overall arrangement of an assembled auxiliary truck,
whereas
Figures 3 and 4 show in phantom outline the placement of the railcar wheel-
axle set.
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As shown in Figures 3 and 4, the railcar wheel axle set one is supported on
the
shoulder pins 2 above and out of contact with the parallel rail tracks 3. As
shown in
Figure 4, the rail tracks 3 often include track hardware between the tracks 3
such as
derailment bumpers 4 shown. In some cases, the top surface of the derailment
bumpers 4 is above the top rail surface by up to 2 inches. This is a
significant concern
to the design of such auxiliary trucks and renders many prior art
configurations
inoperable under modern rail track conditions.
The auxiliary truck is assembled quickly with no tools required by first
assembling
two parallel truck wheel axle assemblies 5 and two railcar wheels support
assemblies
6, then jacking the wheel axle set 1 of the railcar with hydraulic jacks for
example.
Thereafter, the wheel support assemblies 6 can be placed under the railcar
wheel 1 and
attached to the axle assemblies 5 as indicated in Figures 3 and 5.
As best seen in Figure 2, the two parallel truck wheel axle assemblies each
include
two truck wheels 7 which are centrally mounted on stub axles 8 with
appropriate
tapered roller bearings, seals and bearing retention nut 9. A simple grease
gun nipple
10 is provided for lubrication of the bearings.
In order to keep the weigh to individual components down below 90 pounds, the
truck
axle assembly can be taken apart with stub axles 8 having an inward end
releasably
secured to a transverse brace 11. A preferred arrangement is shown in Figure 2
where
the inward ends of the stub axles 8 are slidingly housed inside tubular braces
11 and
secured in place with removable pins 12.
In this way, the individual truck wheels and associated stub axles 8 can be
produced at
under 90 pounds with appropriate weight carrying capacity.
The two railcar wheel support assemblies 6 are quickly assembled from a pair
of
parallel elongate plates 13 with one truck wheel 7 from each of the two axle
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assemblies 5 disposed between the plates 13. As best shown in Figures 3 and 5,
each
plate 13 includes stub axle cradling means for releasably journalling the stub
axles 8.
As illustrated a preferred stub axle cradle takes the shape of a semi-
cylindrical recess
disposed at lower front and rear corners of each plate. The semi-cylindrical
recess has
an open mouth inclined at an acute angle "a" relative to the horizontal. The
location
of the cradle and the inclined acute angle have significant advantage as
illustrated in
Figure 5 and described below in detail.
To prevent wandering of the plates, each stub axle 8 includes restraint means
for
laterally restraining the plates 13. As indicated in Figure 2, the restraint
means
comprise an inner circumferential ridge and an outer C-shaped circumferential
ridge
attached to the outer end of the stub shaft 8 with bolts for example.
As shown in Figure 2, the parallel plates 13 are spaced apart a selected
distance with
15 two shoulder pins 2 which releasably connect a central portion of each
plate 13 with a
spring ring clip 16 in a groove in the outer ends of all pins 2. As indicated
in Figure
3, the pins 2 support the flanged railcar wheel 1 securely between the two
parallel
plates 13.
It has been found by experiment that a weight carrying capacity for the
auxiliary truck
is excess of 75 tons is possible, where each of the individual plates or truck
wheel in
associated stub axle components weighs less than 90 pounds. This feature
enables the
auxiliary truck to be utilized where a heavily loaded railcar or locomotive
encounters
a locked wheel repair situation.
The placement and configuration of the semi-cylindrical recess provides
significant
advantage over prior art trucks for the following reasons. Referring to
Figures 3 and
4, the placement of the semi-cylindrical recess to cradle the stub axle 8
disposed at
lower front and rear corners of each plate 13, enables the plates 13 to pass
over any
derailment bumpers 4 or other track hardware that extends above the head of
the track
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3. Many prior art trucks do not address this problem since they are designed
primarily
for use inside assembly shops or repair yards and do not encounter such track
hardware which is located in external railway track areas.
As shown in Figure 3, location of the stub cradling semi-cylindrical recess in
the
lower corners of each plate, enables the bottom surface of the plate 13 to be
substantially raised above the track 3.
Figure 5 illustrates a further advantage of the open mouth inclined at an
acute angle
relative to the horizontal. For clarity at the right hand side, the outer
ridge 15 has
been removed although during assembly the plate 13 will be inserted between an
outer
ridge 15 and the bearing retention nut 9, as in Figure 2. Figure 5 indicates
that the left
hand connection is made first between the plate 13 and stub axle 8 of the left
hand
wheel. Then the plate 13 is rotated clockwise while the right-hand wheel 7 is
rolled
towards the left as drawn. As can be particularly seen in Figure 5, the acute
angular
orientation "a" permits the lower corner 17 of the open mouth 18 to engage the
stub
shaft 8 as the right-hand wheel 7 is rolled toward the left. When engaged as
shown in
Figure 5, further lowering of the plate 13 will enable the stub shaft 8 to be
guided
accurately into engagement with the open mouth and recess 18. In contrast, if
the
open mouth were not inclined but rather a simple semi-cylindrical recess in
the lower
surface of the plate 13, no such guiding action would be produced.
There is a trade-off when the acute angle is modified and depending on the
design
characteristics desired, the range of acute angle can vary between 5 and 80
degrees
and preferably between 15 and 65 degrees. At the higher end of these ranges,
the
railcar axle need not be raised as high to assemble the truck, however the
retention of
the truck wheel axle assembly is superior towards the lower end of angle
ranges. The
design profile and thickness of the elongate plates is modified to accommodate
the
angular variation as well.
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Although the above description and accompanying drawings relate to specific
preferred embodiments as presently contemplated by the inventor, it will be
understood that the invention in its broad aspect includes mechanical and
functional
equivalents of the elements described and illustrated.
