Methods For Repair And Preventive Maintenance Of Railroad Ties Using UV Curable Polymers

Abstract

A method for repair and preventive maintenance of railroad ties by application of a polymer system to the surface of the rail seat. The polymer system is cured by irradiation with ultraviolet light to fully cure or partially cure the polymer. The polymer system may be used in conjunction with a tie pad that is capable of transmitting ultraviolet light to permit curing of the polymer.

What is claimed is: 
     
         1 . A method for repair and preventive maintenance of railroad ties, comprising the steps of:
 providing a railroad tie having a rail seat;   providing a UV curable epoxy system;   applying the UV curable epoxy system to the rail seat;   curing the UV curable epoxy system by irradiation with ultraviolet light.   
     
     
         2 . The method of  claim 1 , wherein the UV curable epoxy system is cured by irradiation with ultraviolet light for less than 5 minutes. 
     
     
         3 . The method of  claim 1 , wherein the UV curable epoxy system is an epoxy acrylate resin. 
     
     
         4 . The method of  claim 1 , wherein the UV curable epoxy system comprises a photoinitiator that absorbs light in a range of about 300 nm to about 450 nm. 
     
     
         5 . The method of  claim 1 , wherein the UV curable epoxy system is cured with a combination of UV-C light, and UV-A or UV-B light. 
     
     
         6 . The method of  claim 1 , wherein the UV curable epoxy system has a viscosity of about 600 cps. 
     
     
         7 . The method of  claim 1 , wherein the UV curable epoxy system has a viscosity ranging from about 1000 cps to about 2000 cps. 
     
     
         8 . The method of  claim 1 , wherein the UV curable epoxy system has a viscosity of about 24,500 cps. 
     
     
         9 . The method of  claim 8 , wherein the railroad tie is canted. 
     
     
         10 . The method of  claim 1 , wherein the UV curable epoxy system is applied as a coating having a thickness of about ⅛th inch or less. 
     
     
         11 . The method of  claim 10 , wherein the UV curable epoxy system is applied as a coating having a thickness of about 0.024 inches. 
     
     
         12 . The method of  claim 10 , wherein the UV curable epoxy system is cured by irradiation with ultraviolet light for less than 5 seconds. 
     
     
         13 . The method of  claim 1 , wherein the UV curable epoxy system includes a thixotropic agent. 
     
     
         14 . The method of  claim 13 , wherein the thixotropic agent causes the UV curable epoxy system to exhibit different viscosities when subject to shear stress than when at rest. 
     
     
         15 . The method of  claim 1 , wherein the UV curable epoxy system is a 2 part system. 
     
     
         16 . The method of  claim 1 , wherein the UV curable epoxy system is a 1 part system. 
     
     
         17 . The method of  claim 1 , further comprising the step of removing surface water from the railroad tie before applying the UV curable epoxy system to the rail seat. 
     
     
         18 . A method for repair and preventive maintenance of railroad ties, comprising the steps of:
 providing a railroad tie having a rail seat;   providing a UV curable epoxy acrylate resin having a viscosity of about 600 cps;   applying the UV curable epoxy acrylate resin to the rail seat in a thickness of about 0.024 inches;   curing the UV curable epoxy acrylate resin by irradiation with ultraviolet light.