Composite rubber/concrete railroad grade crossing system

A grade crossing system for extending a roadway across a railroad track comprises elongate elastomeric pad units which abut each side of the rails in the track but do not extend across the entire crossing. The elastomeric pad units rest on the ties that carry the rails and have planar top surfaces that are coplanar with the tops of the rails. The remainder of the crossing is filled with non-elastomeric panels that also rest on the ties and have planar top surfaces that are coplanar with the top surface of the rails. The abutting edges of the pad units and the panels overlap such that the panels hold the pad units down against the ties and urge them against the sidewalls of the rail flanges. Thus, mechanical fasteners are not required to hold the crossing elements in place.

BACKGROUND AND SUMMARY OF THE INVENTION 
This invention relates to a railroad grade crossing using a composite of 
elastomeric and non-elastomeric elements, and in particular, to such a 
crossing which does not require mechanical fasteners. 
Many highways and arterials which cross railroad tracks utilize elastomeric 
crossing elements, such as those disclosed in Trickel et al. U.S. Pat. No. 
4,365,743. Crossings, using elastomeric elements not only are inherently 
smoother than crossings made from non-elastomeric materials, but maintain 
their smoothness much longer. Timber crossings, for example, wear quite 
quickly and soon present a rough crossing surface. While asphalt wears 
better than timber, it is difficult to compact asphalt immediately 
adjacent to the rails. Thus, an asphalt grade crossing soon settles 
adjacent to the rails which also creates a rough surface. In addition, it 
is difficult to prevent water from entering between the asphalt and the 
rails and when freezing occurs the water expands and causes deterioration 
of the asphalt. Concrete wears better than asphalt and does not require 
mechanical compaction, however, freezing is a problem with this material 
also. In addition, concrete grade crossings usually have metal edges which 
occasionally causes shorting to occur between the rails which can activate 
the crossing signs. Not only do elastomeric grade crossing elements 
provide greater smoothness, they are easier to remove than timber, 
concrete or asphalt which permits them to be reused when the track is 
brought up to grade by adding ballast and retamping. 
However, grade crossings which utilize elastomeric components are quite 
expensive and, accordingly, it is not economically feasible to use this 
type of crossing for roads which are infrequently traveled. In these 
situations, composite crossing systems having an elastomeric element 
adjacent to the rails and non-elastomeric elements over the remainder of 
the crossing have been utilized. A composite system of this type provides 
many of the advantages of an elastomeric crossing at a much lower cost 
than a full elastomeric system. In addition, a composite system is even 
easier and less expensive to install and to remove than a full elastomeric 
system and thus facilitates repairs to the track and rail bed. One such 
system composite is disclosed in Hales et al. U.S. Pat. No. 4,449,666. 
Rather than pouring the elastomeric portion in place between the rails and 
the non-elastomeric portion as is done in Hales et al., it would be 
simpler and less expensive to use precast elastomeric pads, similar to the 
pads disclosed in Trickle et al., along with precast concrete panels, 
similar to those that are used as crossing elements in their own right. 
The precast concrete panels are heavy and thus do not have to be 
mechanically fastened to the ties. However, the elastomeric pads are too 
light to rely on their own weight to keep them in place and mechanical 
fasteners must be used. This not only increases the installation cost but 
the partial pads that would be used in a composite system would be quite 
narrow and leave little room for fasteners. 
The subject invention overcomes the foregoing shortcomings and limitations 
of the prior art by providing a composite crossing system with elastomeric 
pad units adjacent to the sides of the rails, and non-elastomeric panels 
over the remainder of the crossing. An interfitting joint between each 
elastomeric pad unit and non-elastomeric panel causes the panel to hold 
the pad on the ties. This joint includes an overlapping portion that 
angles upwardly from the ties extending towards the rail. In a preferred 
embodiment, the non-elastomeric panels have metal edge protectors cast in 
them to prevent crumbling due to the impact of vehicular traffic. In 
addition, the non-elastomeric panels include integral attachment devices 
to facilitate their being lifted into place. 
The weight of the non-elastomeric panels holds the crossing elements down 
on the ties, and, since the crossing elements substantially fill the space 
between the roadway and the rails and between the rails, the elements will 
not move perpendicular to the rails. In a preferred embodiment, end 
restraints, that are attached to the ties, prevent the elements from 
moving parallel with the rails. 
Accordingly, it is a principal object of the present invention to provide a 
railroad grade crossing system having elastomeric elements adjacent to 
both sides of the rails and non-elastomeric elements over the remainder of 
the crossing. 
It is a further object of the subject invention to provide such a system in 
which the non-elastomeric elements hold the elastomeric elements down 
against the ties. 
It is a still further object of the subject invention to provide such a 
system in which the nonelastomeric elements urge the elastomeric elements 
against the rail flanges.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring to FIGS. 1 and 2 of the drawings, a composite railroad grade 
crossing system is utilized in connection with a railroad track comprising 
a pair of parallel, side-by-side rails 10 that are attached to a plurality 
of transverse, spaced-apart ties 12. Each rail has a horizontal base 16, 
which in the drawings is shown as being attached to the ties through tie 
plates 18 and spikes 20. The subject crossing system works equally well 
with other types of rail attachment systems. Extending upwardly from the 
base is a thin web 22 having vertical sidewalls 23. An enlarged ball 24 
which carries the rail car wheels (not shown) is located on top of the 
web. 
The grade crossing comprises elastomeric pad units 26 which are located on 
each side of each rail. Each pad unit has a planar bottom surface 28 that 
rests on the ties and a planar top surface 30 that is coplanar with the 
top of the rail ball 24 and supports the wheels of vehicular traffic 
passing over the grade crossing. One end 32 of the pad unit is arranged to 
abut the side wall 23 of the rail web. A cavity 34 defined in the bottom 
of the pad unit fits over the tie plates 18 and spikes 20. The approach 
pad units, which are located on the outside of the rails, have rail 
grinding relief 36, adjacent to the rail ball that accommodates grinding 
the ball, and the center pad units have flange way relief 38 adjacent to 
the rail ball that accommodates the flanges of the rail car wheels. The 
edge 40 of each pad unit that faces away from the rail is in the shape of 
a stair-step, with a vertical face at the top 42 and bottom 44, and an 
intermediate face 46 that angles upwardly from the ties as it extends 
towards the rail 10. The pad units 26 can be made from comminuted rubber, 
as described in Trickel et al. '743, from virgin rubber, or from other 
elastomeric materials having sufficient strength and rigidity to provide a 
roadway surface. 
Located between the two center pad units and between each approach pad unit 
and the roadway are non-elastomeric panels. In the preferred embodiment, 
the panels are cast concrete. There are two approach panels 48a, one 
located between each approach pad unit and the existing roadway. The outer 
end of each approach panel 48 is vertical, and the inner end conformingly 
overlaps with the abutting end of the respective pad unit 26. There is one 
center panel 48b and each of its ends conformingly overlaps the abutting 
end of one of the center pads units. 
The edges of the panels 48a and b have steel edge protectors 50 cast in 
them. The edge protectors are held in place by being attached to the 
reinforcing bar located in the panels and form a wear resistant edge. The 
edge protectors prevent the crumbling that would otherwise occur as a 
result of the repeated traffic loads on the concrete edges. Also located 
at selected locations in the panels 48a and b are attachment devices 52 
for lifting the panels. Referring now also to FIG. 3, each attachment 
device includes a cavity 54 formed in the top surface of the panel and a 
lifting hook 56 that is partially imbedded into the concrete and projects 
into the cavity. 
Due to the weight of the large non-elastomeric panels 48a and b, and the 
overlapping edges between the panels and the pad units 26, the entire 
grade crossing is held in place on the ties 12 without the need for 
fasteners. Also, because of the sloped intermediate faces 46 of the pad 
units, the ends 32 of the pad units are urged into contact with the 
sidewalls 23 of the rails 10. Thus, water is channeled away from the rail 
and will not seep below the crossing where it could cause degradation of 
the roadbed that supports the ties. 
The pad units and panels are sized to completely fill the spaces between 
the rails and between the rails and the roadway. Thus, movement of the 
grade crossing is substantially eliminated in a direction perpendicular to 
the rails. Movement of the grade crossing in a direction parallel with the 
rails is prevented by panel restraints 58. Referring now also to FIG. 4, 
each panel restraint 58 comprises a vertical pad 60 with a horizontally 
extending leg 62 attached to it. One of the panel restraints is placed at 
each end of each panel 48a, b and is attached to a tie 13 by means of 
spikes 64. The panel restraints extend over a portion of the pad units 
also, and thus prevent movement of the entire crossing in a direction 
parallel with the rails. 
The terms and expressions which have been employed in the foregoing 
specification are used therein as terms of description and not of 
limitation, and there is no intention, in the use of such terms and 
expressions, of excluding equivalents of the features shown and described 
or portions thereof, it being recognized that the scope of the invention 
is defined and limited only by the claims which follow.