Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02416090 2003-O1-09
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Background of the Invention
The invention relates generally to railcars, and more particularly to an
improved railcar for carrying automotive vehicles in commercial rail service.
For many years, tri-level auto rack railcars have been constructed by building
racks on flatcars. In conventional railcars of this type, the deck of the
flatcar functions
as the first deck of the tri-level car, and the second and third decks are
supported by
the rack. The first, second and third decks are commonly referred to as the A,
B and
C decks respectively. The A deck typically has a depressed center portion
between
the trucks, whereas the B and C decks are at a generally uniform elevation
along the
length of the car. The clearance over the A deck is accordingly greater along
the
depressed portion.
Conventional tri-level cars have hinged end sections on their B decks to
I S increase clearance or drive-in height at the ends of the A decks. The
hinged end
sections are pivotable between raised positions for providing increased
clearance, and
lowered positions for supporting automotive vehicles. The end sections are
typically
raised and lowered manually during loading and unloading operations. To
facilitate
controlled raising and lowering of the end sections, springs are typically
provided to
apply upward force to the hinged sections when they are in their lowered
positions.
The clearances at the ends of the A deck are typically quite limited when the
hinged end sections of the B decks are in their lowered positions.
Accordingly, in a
typical tri-level railcar carrying 5 automobiles on each deck, the positions
at each end
of the A deck, i.e., the Al and Aj positions, must be occupied by automotive
vehicles
with very low profiles, or otherwise must remain empty during transport. Thus,
while
CA 02416090 2003-O1-09
the hinged end sections of the B deck permit flexibility in carrying various
types of
automotive vehicles in the three middle locations on the A deck, the A 1 and
A~
positions are of limited utility.
In order for a railcar to be commercially viable for use in commercial
service,
the rack structure must have sul~fucient strength and rigidity to withstand
many years
of dynamic loading during transport of vehicles. The loading on the rack
includes
longitudinal loads associated with acceleration and deceleration of the
railcar, as well
as various other loads associated with the motion of the car, the weight of
the motor
vehicles supported on the rack, loading and unloading of the motor vehicles,
and the
weight of the rack itself.
The rack structure typically relies on vertical posts to support the B and C
decks, and relies on the B and C decks themselves to contribute strength and
rigidity
to the rack. The hinged end sections of the B decks must have sufficient
strength and
rigidity to support the weight of motor vehicles during loading, unloading,
and
transport when in their lowered positions, but typically do not otherwise
contribute
significant strength or rigidity to the rack structure. Among other structural
members
of the rack, a cross-brace or brace bay is typically included in each side
wall between
the A and B decks and between a pair of posts near the hinged joint associated
with
each of the hinged end sections of the B deck.
While tri-level railcars have proven to be a safe, cost efficient option for
transportation of automotive vehicles, room for improvement remains in certain
areas.
One problem is that the brace bay contributes weight and expense to the
railcar, and
also locally reduces interior width, limiting the vehicle width that can be
accommodated, and limiting the space available for drivers to walk past the
vehicles
during loading and unloading operations. Another problem is that the hinged
sections
of the B deck contribute expense without significantly contributing strength
and
CA 02416090 2003-O1-09
rigidity to the rack structure. The need to raise and lower the hinged
sections also
increases the time required for loading and unloading, and adds to the amount
of labor
required in loading and unloading operations. In addition, the hinged sections
require
lubrication and other maintenance.
Various alternatives to the conventional tri-level cars described above have
been developed. It is believed that in some tri-level railcars manufactured
and sold in
the United States several years ago, the hinged end sections of the B deck did
not
extend the full width of the B deck. In these cars, the B deck had fixed edge
portions
extending along the entire length of the railcar. Other tri-level auto rack
cars are
described and shown in U.S. Patent No. ~,979,33~ and U.S. Patent No.
6,273,004.
There remains a need for further improvements in methods and apparatus for
transport of automotive vehicles by rail.
Summary of the Invention
The invention provides a tri-level railcar that eliminates the conventional
hinged end sections of the B deck. The B deck is prei:erably fixed, i.e.,
bolted or
welded in place along its entire length, rather than having hinged end
sections as in
the prior art cars discussed above, so that the B deck contributes to the
strength and
rigidity of the car. To provide sufficient clearance in the Al and A5
positions, the B
deck is positioned at a higher elevation than in conventional auto rack cars.
A
minimum clearance of 65 15/16", plus or minus 1'/2", measured 30" off center,
may be
provided for each of the three decks. Clearances above each of the three decks
may be
approximately equal. The car is preferably capable of carrying automotive
vehicles
up to about 63" in height, including the PT Cruiser on each of the decks,
without
requiring any upward displacement of end sections of the B deck to accommodate
such vehicles on the A deck. .
CA 02416090 2003-O1-09
The railcar may be based on a conventional flat car, an upsilI flat car, or a
flat
car having a 39%" ATR (above top of rail) running surface. To facilitate
maintenance
of appropriate clearances, high cambered decks are preferably employed at both
the B
and C level. The overall height of the railcar is preferably the maximum
permissible
height, which under current regulations is 20'2".
Provision of fixed decks facilitates loading in that the all three decks may
be
continuously loaded and unloaded without the need to stop loading and
unloading to
pivot the B deck end sections. Thus, circus loading is much more efficient.
The ability of the B deck to function as a structural member of the railcar
from
end to end may eliminate the need for cross braces, i.e., brace bays, as
included in
typical prior art tri-level auto racks. Elimination of the brace bays may
reduce costs
and weight, and may also increase interior clearances, and simplify door edge
protection.
The railcar described above may also eliminate the need for heavier posts at
1 ~ certain locations. In conventional tri-level auto rack ears, the number 3
and number 4
posts, i.e., the third and fourth posts from the end of the car, are often
heavier than
other posts. The railcar described herein may eliminate the need for these
heavier
posts.
The railcar may also have identical B and C deck assemblies, thus greatly
reducing the number of parts needed to build the rack. That is ,rather than
having a B
inner deck, two B outer decks, and a C deck, the car may have identical B and
C
decks. In commercial production, this would reduce the number of machine
setups
required to manufacture parts, and would reduce the number of materials needed
in
inventory. It is likely that this would also reduce the costs of parts, since
they would
2~ be manufactured and/or purchased from suppliers in Greater numbers. Similar
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economies of scale would also be possible with the post assemblies, due to the
greater
number of standard posts and the elimination of the need for conventional
cross braces
and heavier posts at certain locations.
Parts that are included in a conventional tri-level auto rack but eliminated m
the preferred auto rack of the invention include four hinge assemblies, four
hinge
support assemblies, 8 cone assemblies on posts and 8 on-deck cone assemblies,
four
deck support assemblies on posts and four on hinge decks, four deck lock
receivers.
four deck lock assemblies, four deck lift chain and/or spring assemblies, and
8 lift
attachment assemblies. These parts would be replaced with 24 standard bolting
plates, with a great reduction in labor and fixturing.
The preferred embodiment may also feature additional improvements
including lighter post tubes, smaller post gussets at the joint between the
post and the
fiat car, lighter knee braces, and lighter bolting plates. Shear plates may be
used
between some or all adjacent posts.
In the preferred methods of manufacturing the railcar of the invention,
automatic welding and robotic assembly may be used to a greater extent than in
the
past, due to the reduced number of different parts and greater number of
identical
parts. The costs of fixtures would also be reduced for the same reasons.
Use of the preferred embodiment in commercial rail service would, of course,
eliminate the significant lubrication and maintenance requirements associated
with the
hinged deck sections on conventional tri-levels.
Brief Description of the Drawing-s
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Fig. I is a side e(ev~ational view of a railcar in accordance with a preferred
embodiment of the invention.
Fig. 2 is an end elevational view of the car of :l~ig. 1, with one of the end
doors
removed.
Fig. 3 is a transverse sectional view taken substantially along line 3-3 in
Fig. 1.
Detailed Description of Preferred Embodiment
The invention is preferably embodied in a tri-Ieve1 auto rack railcar 10. The
railcar comprises a flatcar 12 having a rack structure constructed thereon.
The flatcar
has a deck that functions as the A deck of the railcar. The A deck has a
depressed
center portion 14 between the trucks, and end portions 1 ~ at higher
elevations. The
rack structure comprises a plurality of vertical posts 16, and B and C decks
18 and 20
respectively supported by the posts.
Each of the decks is connected to the posts by vertical plates 22 and knee
braces 24. Tire guides 2b and a chock track 28 are provided on each deck.
Longitudinal members 30 such as roof rails and/or top chords tie the vertical
posts
together at their upper ends. A corrugated roof 32 encloses the top of the
car. Radial
end doors 34 having a top panel overlying an end portion of the roof sheet and
pivotally attached thereto are preferably employed at each end of the car.
The B deck 18 is fixed along its entire length, rather than having hinged end
sections as in the prior art cars discussed above, so that the B deck
contributes to the
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CA 02416090 2003-O1-09
strength and rigidity of the rack structure. To provide sufficient clearance
in the A 1
and A5 positions, the B deck is positioned at a higher elevation than in
conventional
auto rack cars. Winimum clearances of ha, h6, and h~_ measured 30" off center,
are
maintained above the A, B and C decks respectively. A minimum clearance of 65
15/16", plus or minus i'/~", may be provided for each of the three decks.
Clearances
above each of the three decks may be approximately equal. The car is
preferably
capable of accommodating automotive vehicles up to about 63" in height,
including
vehicles such as the Chrysler PT Cruiser.
The railcar may be based on a conventional flat car, an upsill flat car, or a
flat
car having a 39'/z" ATR (above top of rail) running surface. To facilitate
maintenance
of appropriate clearances, high cambered decks are preferably employed at both
the B
and C level. The overall height of the railcar is preferably equal to the
maximum
height permissible under AAR regulations or other applicable regulations,
i.e., 20' 2".
Provision of fixed decks facilitates loading in that the all three decks may
be
1-S continuously loaded and unloaded without the need to stop loading and
unloading to
pivot the B deck end sections. Thus, circus loading is much more efficient.
The ability of the B deck 18 to function as a structural member of the railcar
from end to end may eliminate the need for cross braces, i.e., brace bays, as
included
in typical prior art tri-level auto racks. Elimination of the brace bays may
reduce costs
and weight, and may also increase interior clearances, and simplify door edge
protection.
The railcar described above may also eliminate the need for heavier posts at
certain locations. In existing auto rack cars, the number 3 and number 4
posts, i.e., the
third and fourth posts from the end of the car, are often. heavier than other
posts. In
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the illustrated embodiment of the invention, all ofthe posts may be of the
same or
similar cross-section.
The invention is not Limited to the preferred embodiment described above.
The invention is further described in the followin; claims.
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