Vibration dampening railway tie boot

Abstract

A vibration dampening boot for railway tie blocks and a method of manufacturing railway tie block assemblies. The boot includes a bottom wall with resilient tie block contact structures disposed at different heights for initial tie block support and variable vibration dampening. The upper portion of the boot terminates in a removable wall connected to the side walls of the boot by a relatively thin tear strip to enable direct pouring of cast material, such as concrete or epoxy, into the boot for casting the tie block, with the wall removable after installation of the tie block assembly into a railway bed. In this manner, the boot may be used with pre-cast tie blocks as well as accommodate direct casting of the tie blocks within the boot to form a tie block assembly.

What is claimed is: 
     
         1 . A railway tie block boot, comprising:
 a bottom wall made of a resiliently deformable material;   a plurality of side walls extending upwardly from the bottom wall and terminating in an upper lip extending around a periphery defined by the side walls, such that the bottom wall and the plurality of side walls cooperate to form a generally rectangular box-like structure with an open upper end; and   a removable wall extending upwardly from the upper lip and extending around the periphery of the side walls, the removable wall tapering inwardly from the upper lip toward the open upper end.   
     
     
         2 . The railway tie block boot of  claim 1 , wherein the plurality of side walls splay outwardly at the open upper end. 
     
     
         3 . The railway tie block boot of  claim 1 , wherein the removable wall is connected to the upper lip by a tear portion of reduced thickness relative to the upper lip and the side walls 
     
     
         4 . The railway tie block boot of  claim 3 , wherein the reduced thickness of the removable wall is thin enough to allow a user to grasp a portion of removable wall and tear the removable wall away from the plurality of side walls by hand, and without the use of tools. 
     
     
         5 . The railway tie block boot of  claim 1 , wherein the resiliently deformable material is rubber has a durometer between 45 and 80 on the shore A scale. 
     
     
         6 . The railway tie block boot of  claim 5 , wherein the rectangular box-like structure of the railway tie block boot is about 31.5 inches long, 11.8 inches wide, and 5.9 inches deep, whereby the railway tie block boot is compatible for use in rail beds for light rail applications. 
     
     
         7 . The railway tie block boot of  claim 1 , in combination with a cast tie block receivable within the railway tie block boot, the cast tie block having a tapered upper portion corresponding to the taper of the removable wall. 
     
     
         8 . The railway tie block boot of  claim 1 , wherein:
 the bottom wall has a first plurality of tie block contact features disposed at a first, upper elevation with respect to the bottom wall and a second plurality of tie block contact features disposed at a second, lower elevation with respect to the bottom wall, with a plurality of recesses defined between the first and second tie block contact features.   
     
     
         9 . A railway tie block boot, comprising:
 a bottom wall sized and configured to support a railway tie block, the bottom wall having a ribbed structure formed on an upwardly-facing surface thereof and defining a plurality of lands and valleys; and   a plurality of side walls extending from the bottom wall and terminating in an upper lip spaced from the bottom wall and extending around the side walls.   
     
     
         10 . The railway tie block boot of  claim 9 , further comprising a removable wall extending from the upper lip and extending circumferentially around the side walls, the removable wall connected to the upper lip by a tear portion of reduced thickness relative to the upper lip and the side walls. 
     
     
         11 . The railway tie block boot of  claim 9 , wherein the plurality of side walls further comprise a second set of lands and valleys, each of the second set of lands extending circumferentially around the plurality of side walls. 
     
     
         12 . The railway tie block boot of  claim 9 , wherein the lands of the ribbed structure are all substantially coplanar. 
     
     
         13 . The railway tie block boot of  claim 9 , wherein the lands of the bottom wall comprise a first set of lands disposed at a first, upper elevation with respect to the bottom wall and a second set of lands disposed at a second, lower elevation with respect to the bottom wall. 
     
     
         14 . The railway tie block boot of  claim 13 , wherein the first set of lands alternate with the second set of lands throughout the ribbed structure, such that respective individual lands of the first set of lands are disposed between a neighboring pair of the second set of lands. 
     
     
         15 . The railway tie block boot of  claim 9 , wherein the plurality of lands and valleys are regularly spaced and arranged to provide a consistent reaction force when subjected to downward and lateral forces. 
     
     
         16 . The railway tie block boot of  claim 9 , wherein the plurality of lands and valleys cooperate to form a trapezoid wave form in cross section. 
     
     
         17 . The railway tie block boot of  claim 16 , wherein the plurality of lands and valleys defines a frequency between 0.65 inches and 1.0 inches and a height between 0.2 and 0.3 inches, 
     
     
         18 . The railway tie block boot of  claim 17 , wherein:
 the plurality of lands each has an upper surface defining a lateral extent between 0.30 and 0.45 inches,   the plurality of valleys each defines a width between 0.2 and 0.3 inches, and an angle defined by the upward and downward slopes flanking each of the plurality of lands is between 50 degrees and 70 degrees.   
     
     
         19 . The railway tie block boot of  claim 9 , wherein the bottom wall and the plurality of side walls are monolithically formed from a single piece of material. 
     
     
         20 . The railway tie block boot of  claim 9 , in combination with a cast tie block receivable within the railway tie block boot, the cast tie block formed from one of concrete and an epoxy polymer material cast material. 
     
     
         21 . A method of assembling a tie block to a tie block boot, the tie block boot having a bottom wall, a plurality of side walls extending upwardly from the bottom wall and terminating in an upper lip extending around a periphery defined by the side walls, and a removable wall extending upwardly from the upper lip, the method comprising:
 folding the removable wall down around the side wall;   seating the tie block into the tie block boot such that the tie block is support by the bottom wall and abuts the plurality of side walls; and   unfolding the removable wall such that an inwardly-tapered portion of the removable wall is allowed to conform to an adjacent inwardly-tapered portion of the tie block.   
     
     
         22 . The method of  claim 21 , further comprising installing the tie block and tie block boot into a railbed without removing the removable wall. 
     
     
         23 . The method of  claim 21 , further comprising removing the removable wall by one of cutting and tearing. 
     
     
         24 . The method of  claim 21 , wherein the step of seating the tie block into the tie block boot comprises lowering a precast tie block into engagement with the bottom wall. 
     
     
         25 . The method of  claim 24 , wherein the step of lowering a precast tie block into engagement with the bottom wall comprises engaging a set of lands and valleys formed in the plurality of side walls, the land and valleys configured to reduce surface-area contact, and therefore friction, between the upright surfaces of the tie block and the corresponding inner surfaces of the plurality of side walls. 
     
     
         26 . The method of  claim 21 , wherein the step of seating the tie block into the tie block boot comprises casting the tie block directly into the tie block boot, such that the tie block boot serves as a casting mold.