Internally resilient tie for railway track

Abstract

The Internally Resilient Railroad Tie consists of two independent booted blocks placed in a tie case, one under each rail. An elastomeric bottom pad is placed under each block inside the boot. The stiffness of the elastomeric bottom pad is varied to compensate for the variations of the overall stiffniess of the track that often involves under-lying materials that are difficult to access for modification or replacement. The mass of the block, suspended between the elastomeric bottom pad and the elastomeric rail pad, provides a damper action that along with the enhanced elasticity of the assembly reduces dynamic impact forces and abates vibrations. The damper system reduces the duration and significance of dynamic peak forces and vibrations. However, variations of any or all of the damper system's components can be used to compensate for the variations of the overall dynamic response of the track where needed. A block retainer facilitates lifting whole tie assembly by rail during track installation and maintenance, as well as releasing the blocks during replacements of the bottom elastomeric pad. In service, the block retainer preferably does not restrain elastomers and allows for the rail float. This feature leads to further reduction of track maintenance. In weak soils, or where the carrying participation of ballast and/or surface soils is undesirable or unfeasible, the internally resilient ties can be placed on piles, pile caps, longitudinal beams, firm foundations, bridge decks and tunnel inverts because the internally resilient tie is capable of substituting for ballast action and for the elastic contributions of subgrade. Internally resilient ties are suitable for transition zones between ballasted and ballastless track zones.

1 . What I claim as my invention is an internally resilient railroad tie, a tie containing two blocks placed in the tie case, independent of each other, one under each rail, further equipped as follows: Each block is placed in an elastomeric enclosure termed the boot. An elastomeric bottom pad is placed under each block inside each boot. The elastomeric bottom pad is supplied and applied in various values of stiffness to compensate for the lack or excess of the overall track stiffness at each tie location along the track. The mass of the block, the elastomeric bottom pad, and an elastomeric rail pad placed on the top of the block under the rail create a damper, a system consisting of a mass suspended between two elastic members. The properties of this damper system are adjustable by varying any or all of its components to compensate for variations of the overall dynamic response of the track.  
     
     
         2 . The closure of  claim 1  wherein the block is made of concrete  
     
     
         3 . The closure of  claim 1  wherein the block is made of steel  
     
     
         4 . The closure of  claim 1  wherein the block is made of cast iron  
     
     
         5 . The closure of  claim 1  wherein the block is made of a concrete/steel combination  
     
     
         6 . The closure of  claim 1  wherein the block is made of plastic  
     
     
         7 . The closure of  claim 1  wherein the block is made of wood  
     
     
         8 . The closure of  claim 1  wherein the tie case is made of concrete  
     
     
         9 . The closure of  claim 1  wherein the tie case is made of steel  
     
     
         10 . The closure of  claim 1  wherein the tie case is made of cast iron  
     
     
         11 . The closure of  claim 1  wherein the tie case is placed on ballast  
     
     
         12 . The closure of  claim 1  wherein the tie case is placed on piles  
     
     
         13 . The closure of  claim 1  wherein the tie case is placed on pile caps  
     
     
         14 . The closure of  claim 1  wherein the tie case is placed on longitudinal beams  
     
     
         15 . The closure of  claim 1  wherein the tie case is placed on a firm foundation such as rock, structural foundation created for this purpose, a tunnel invert or a bridge slab.  
     
     
         16 . What I claim as my invention is the block of the internally resilient tie equipped with a block retainer, a device for retaining blocks in the tie when complete rail tie assemblies are lifted and moved by the rail during track installation and maintenance, and for releasing the blocks from the tie when the bottom elastomeric pad or the boot has to be replaced or removed.  
     
     
         17 . The closure of  claim 16  wherein the block retainer and the block are not contiguous in service because the block retainer allows each block to follow the deflection of elastomers and the uplift wave of the rail within certain travel.  
     
     
         18 . The closure of  claim 16  wherein the block retainer consists of cast iron insert equipped with a shank for anchorage in the concrete mass of the tie case, and with a curved slot at its top to receive spring leaves, held in the slot by their flexural pre-loads and secured by a vertical pin inserted into aligned holes in the leaves and in the shoulder as shown on the Drawing  3 .  
     
     
         19 . The closure of  claim 16  wherein the block retainer consists of cast iron insert equipped with a threaded extension for its attachment to the steel tie case, and with a curved slot at its top to receive spring leaves, held in the slot by their flexural pre-loads and secured by a pin inserted into aligned holes in the leaves and the shoulder as shown on the Drawing  4 .  
     
     
         20 . What I claim as my invention is the block of the internally resilient tie equipped with a device for rain water diversion and enhancement of electrical insulation properties of the block by the non-metallic collar attached to the block's perimeter and/or by the overhang-shaped elastomeric boot's edge to create dry areas under the collar, and/or under the lip of the boot in order to interrupt surface passage of electric currents, and to keep rainwater from entering the tie's interior along the vertical surfaces of the boot.