Railyway sleepers

Abstract

A dimensionally stable combination of wood and inorganic material is provided as railway sleepers or ties. The wood is preferably a softwood impregnated with an alkali-metal or alkaline earth-metal silicate solution, which has been rendered water insoluble after impregnation. Preferably sodium silicate (water glass) is used as the solution. Any cracks, gaps, shakes, splits, or the like, remaining after impregnation are filled so as to deny entry of water, ice, snow, and debris into such cracks, etc. Predrilled holes in the ties receive deeply threaded railway spikes, capped by a hexagonal cap to hold the rails. Preferably, the spikes and caps are coated with a similar solution to provide both corrosion protection and strong bonding of the components.

I claim: 
     
         1 . A railway sleeper formed of a dimensionally stable combination of wood and an impregnated alkali- or alkaline earth metal silicate which silicate has been rendered water insoluble. 
     
     
         2 . The railway sleeper of  claim 1 , wherein the silicate is sodium silicate. 
     
     
         3 . The railway sleeper of  claim 1 , wherein the wood is selected from the group consisting of softwoods. 
     
     
         4 . The railway sleeper of  claim 1 , wherein the wood is Southern Yellow Pine. 
     
     
         5 . The railway sleeper of  claim 1 , wherein surface voids in the sleeper are filled with a paste of calcium powder mixed with an alkali-metal silicate. 
     
     
         6 . The railway sleeper of  claim 1 , wherein surface voids in the sleeper are filled with a water insoluble material, optionally containing a filler. 
     
     
         7 . The railway sleeper of  claim 6 , wherein the insoluble material is selected from glue and resin. 
     
     
         8 . The railway sleeper of  claim 6 , wherein the filler is present and is one selected from the group consisting of wood and sawdust. 
     
     
         9 . The railway sleeper of  claim 1 , wherein surface voids in the sleeper are filled with a water soluble or partially soluble material that is coated with a water insoluble material. 
     
     
         10 . A process of making a railway bed comprising installing the railway sleeper of  claim 1  on a railway bed and attaching rails to the sleeper. 
     
     
         11 . The process of  claim 10 , wherein the sleeper is provided with factory installed railway spikes extending above a top surface of the sleeper. 
     
     
         12 . The process of  claim 11 , wherein the railway spikes are deeply threaded and are installed in holes drilled partially into the sleeper during manufacture of the sleeper. 
     
     
         13 . The process of  claim 12 , wherein the portion of the railway spike extending above the surface of the sleeper is engaged by a hexagonal shaped threaded cap. 
     
     
         14 . The process of  claim 13 , wherein the threaded cap and spike are coated with an alkali- or alkali-metal silicate. 
     
     
         15 . The process of  claim 14 , wherein the silicate acts as both a bonding agent and corrosion inhibitor. 
     
     
         16 . A railway comprising a plurality of the railway sleepers of  claim 1 , the sleepers supporting rails installed on the sleepers and a ballast beneath and between adjacent sleepers.