Composite rail tie apparatus and method

Abstract

A railroad crosstie (tie) may be fabricated from a composite material including a fiber reinforced polymer shell manufactured by pultrusion or other process, and filled by a suitable material, typically selected from expanded elastomeric polymer (such as polyurethane resin or other polymer), concrete, lightweight concrete formed by conventional aggregate, sand, cement, water, and an ultra light filler such as natural materials, sawdust, beads of expanded polymer such as expanded polystyrene, microspheres of glass or plastic, a recycled wooden tie in conjunction with any of the above, or the like. Fasteners may be driven such as spikes, threaded, such as screws, lag screws, spreading screws, rivets, or the like into apertures, pilot holes, or directly into fill absent apertures therein.

What is claimed and desired to be secured by United States Letters Patent is: 
     
         1 - 14 . (canceled) 
     
     
         15 . An apparatus, shaped as a rail tie and comprising:
 a shell formed of materials resistant to bending and to environmental damage;   a first fill as a solid within the shell;   a second fill, pourable and distinct from the first fill, supporting the first fill by filling spaces inside the shell left by the first fill; and   The first and second fill being configured to receive fasteners penetrating thereinto.   
     
     
         16 . The rail tie of  claim 15  wherein the first fill is resistant to bending. 
     
     
         17 . The rail tie of  claim 16 , wherein the first fill is selected from recycled rubber, polymeric fibers, fibrous solids, and wood. 
     
     
         18 . The rail tie of  claim 15 , wherein:
 the materials forming the first and second fills are configured to receive and directly engage securely therewithin the fasteners; and   the first fill is a solid, at all stages of formation of the apparatus, configured as at least one of particles, fibers, and a continuous member.   
     
     
         19 . The apparatus of  claim 15 , wherein the solid is configured as at least one of particles, fibers, and a continuous member. 
     
     
         20 . The apparatus of  claim 15 , wherein:
 the second fill is selected from concrete, lightweight concrete, polymer, filled polymer, composite polymer, expanded polymer, and a combination thereof; and   the second fill has a shear strength different from that of the first fill.   
     
     
         21 . The apparatus of  claim 15 , wherein the first and second fills are selected to be capable of frictionally securing the fasteners within the shell by compression. 
     
     
         22 . The apparatus of  claim 15 , wherein the fasteners are selected from a spike, a screw, a lag screw, a rivet, a barbed spike, a spreadable spike, a spreadable screw, and a bonded fastener effective to compress a portion of the solid. 
     
     
         23 . The apparatus of  claim 15 , wherein:
 the first fill is characterized by gaps filled by the second fill; and   the first fill comprises a constituent of lower density than that of the second fill.   
     
     
         24 . The apparatus of  claim 15 , wherein the first fill is a solid at all stages of formation of the apparatus. 
     
     
         25 . An apparatus, functional as a rail tie and comprising:
 a shell capable of resisting bending and compression;   a first fill inside the shell and capable of resisting compression and bending of the apparatus;   a second fill inside the shell supporting the first fill by backfilling spaces located in at least one of spaces between the first fill and cavities within the first fill;   the shell, first fill, and second fill being configured together to receive a fastener penetrating through the shell and into the first and second fills.   
     
     
         26 . The apparatus of  claim 25 , wherein the first fill is a solid. 
     
     
         27 . The apparatus of  claim 26 , wherein the first fill remains a solid throughout formation of the apparatus. 
     
     
         28 . The apparatus of  claim 27 , wherein the first fill is configured as at least one of particles, fibers, and a continuous member. 
     
     
         29 . The apparatus of  claim 25 , wherein the second fill is selected from concrete, aerated concrete, lightweight-filled concrete, polymer, filled polymer, composite polymer, expanded polymer, and a combination of at least two thereof 
     
     
         30 . The apparatus of  claim 25 , wherein the second fill fits at least partially within the first fill and has a shear strength different from that of the first fill. 
     
     
         31 . The method of  claim 25 , wherein the first and second fills are capable of securing the fasteners based on elastic resilience of at least one of the first fill and the second fill. 
     
     
         32 . The apparatus of  claim 31 , wherein the first and second fills are configured to receive the fasteners of a type selected from a spike, a screw, a lag screw, a rivet, a barbed spike, a spreadable spike, a spreadable screw, and a bonded solid member. 
     
     
         33 . The apparatus of  claim 25  comprising a third fill distinct from the first and second fills and selected to change a physical property of the apparatus selected from stiffness, density, strength, elasticity, toughness, softness, friction, and deflection under load. 
     
     
         34 . A method of supporting a rail as a track in a railroad, the method comprising:
 providing an apparatus capable of operating as a rail tie and including a shell defining a length and containing a first fill and a second fill dispersed throughout the shell;   positioning the apparatus on a ballast;   positioning a rail on the apparatus;   securing the apparatus to the rail by penetrating the shell, the first fill, and the second fill onsite with fasteners securing the rail onto the apparatus.