Railways: surface track – Rail seats – Cushions
Reexamination Certificate
2003-01-13
2004-06-22
Jules, Frantz F. (Department: 3617)
Railways: surface track
Rail seats
Cushions
C238S005000, C238S008000
Reexamination Certificate
active
06752322
ABSTRACT:
The invention relates to a method of constructing a rail track on a track-receiving concrete slab provided with channels serving to receive the rails of the rail track. The invention is particularly applicable to constructing rail tracks for a subway or a tramway.
BACKGROUND OF THE INVENTION
Methods of constructing rail tracks are known that use a track-receiving concrete slab, such methods being increasingly frequently used because they make it possible for the rate of construction of the track-receiving slab to be very fast. In such methods, wet concrete is generally continuously cast by an automatic machine that follows the path of the track to be built, the machine having a sliding mold or “slip form” provided with two grooves for forming the channels in the slab of concrete. After the concrete has set, the rails are laid in segments in the channels, they are welded end-to-end, and they are then chocked manually to the desired height, and spaced apart to the desired gauge, with clearance being left relative to the edges of the channels. A resilient material such as resin is then cast into the channels.
That technique is fast for laying the concrete, but it suffers from the drawback of being slow for laying and chocking the rails. It is therefore confined to portions that are quite short, such as level-crossing portions.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention is to remedy that drawback by proposing a method of constructing a rail track on a concrete slab in which the rails can be put in place in the channels much faster.
To this end, the invention provides a method of constructing a rail track on a track-receiving concrete slab provided with channels serving to receive the rails of the rail track, wherein, after the concrete forming the track-receiving slab has set, it comprises at least the following steps:
a) the stretches of rail are put in place above the channels in the track-receiving slab, each rail having a foot coated with a casing of resilient material whose thickness is such that the foot as coated with its casing is slightly wider than the channel; and
b) the foot as coated with its casing is inserted into the channel by force, the shape of the channel being suitable for reacting to the compression forces from the resilient material of the casing with a reactive force tending to hold the rail at the bottom of the channel.
In particular embodiments, the construction method of the invention may have one or more of the following characteristics, taken in isolation or in any technically feasible combination:
in an additional step c), the empty volume situated in the top portion of the channel on either side of the rail is filled with resin which seals the installation;
prior to step a), the rails in each stretch are welded together end-to-end;
at least locally, each channel has a width that tapers going from the bottom to the top of the channel;
said channels are of trapezium-shaped cross-section, the larger base of the trapezium constituting the bottom of the channel;
the edges of the channel are inclined at in the range 3° to 15° relative to the plane perpendicular to the bottom of the channel;
the casing coating the foot of each of the rails has a shape that has extra thickness of a few millimeters relative to the complementary shape of the channel;
prior to step c), a primer is deposited on the edges of the channel, and on the sides of the rail so as to improve the adhesive keying of the resin; and
the track-receiving slab is obtained by casting a mass of wet concrete continuously along a determined path.
REFERENCES:
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patent: 4629118 (1986-12-01), Langman
patent: 5788153 (1998-08-01), Ortwein
patent: 6471138 (2002-10-01), Blank et al.
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patent: 196 04 887 (1997-08-01), None
patent: 19604887 (1997-08-01), None
patent: 468 182 (1937-06-01), None
Ehrsam Jean
Skific Yvan
Alstom
Jules Frantz F.
Sughrue & Mion, PLLC
LandOfFree
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