Patent Application
20190211512
This invention relates to railway ties. In particular, this invention relates to railway ties having a keyway below an overlying rail to constrain lateral and longitudinal movement of the rail. The invention also provides a means to attach the rail plate and pad to the tie in which the attachment means is protected from damage. The invention also provides an inspection mechanism for determination of whether the assembly is properly secured to the tie.
As a train runs along a set of rails, it applies lateral forces to the rails, pushing them outward at the point where they are fastened to the supporting ties. It is obviously desirable to minimize the effect of these lateral forces, as any excessive movement of the rail will move the rails heads apart, widening the gauge of the track and allowing the train wheels to slip off the inside of the rail, causing a derailment. Of equal concern is the longitudinal force applied to the rail as the train runs along the rails and due to temperature changes. This force tends to push or pull the rail, and the rail plate holding it to the rail, off the edge of the tie, leaving that portion of the rail unsupported and weak, or disrupting the rail anchoring to the tie to resist thermal longitudinal force, again leading to the possibility of a derailment.
It is known to minimize the effects of the train's forces by securing the rails and ties against movement. For example, U.S. Pat. No. 9,758,932 to Lu et al. describes a ballastless track system wherein concrete slabs carrying the rails are provided with a depending structure on its underside that interacts with the underlying base to try to restrain movement of the entire slab and the overlying rails. However, such systems do not restrict the movement of the rails themselves, apart from the entire assembly as a whole. This may be less efficient and effective.
More typically, movement of a rail supported on a tie is directly restricted by holding it down on a rail plate, which usually includes a rail seat to accommodate the base of the rail. The rail or rail plate is in turn secured to the tie by fasteners. The fasteners are generally exposed on the tie, which can simplify the inspection, repair and/or replacement of the fasteners as needed. However, in a derailment, these fasteners are vulnerable to damage when one or more train wheels forcefully impacts the area beside the rail. This can significantly delay repair after a derailment, and the return of the rail to full availability. Simply covering the fasteners can make it very difficult to inspect the assembly throughout its lifetime, in order o confirm that it properly secures the rail or rail plate. If the assembly is not secured or loosens over time, a catastrophic separation of the rail from the tie may occur.
U.S. Pat. No. 2,276,799 to Spencer and U.S. Pat. No. 715698 to Saleme both provide ties having shaped keyways in their upper surfaces, in order to interlock with components passing over the tie. Saleme discloses a longitudinal passageway through which a rail base is fed. Spencer discloses a lateral passageway, either in a rail plate or in the tie surface, into which a projection on the underside of the rail is fitted and slides horizontally to interlock with the tie or rail plate. The configuration of the rail and the keyed surface are both relatively complex and would not seem to provide the expected lateral support to a rail.
GB Patent No. 1169715 to Waters discloses a rail for which additional lateral support is provided by using a rail with a depending rib that is located in a linear recess extending across the tie, with a resilient pad between the rail and the tie. In another embodiment, Waters provides a standard rail, and a resilient pad having a depending rib that fits into the recess. However, the first embodiment is likely susceptible to abrasion and deterioration between the rail base and the tie, as there is no plate between them. In the second embodiment, having the resilient pad seems to provide less additional lateral support to the rail than would a stiffer or stronger piece, such as the rail base or a rail plate.
U.S. Pat. No. 2,242,773 to Boyce discloses a tie plate with a pair of ribs on an under surface that are embedded in a tie. These are located towards the outer edge of the plate, just outside the rail base. U.S. Pat. No. 4,108,378 to Raymond discloses a rail plate having depending ribs, and a tie having a recess with grooves running across the width of the tie. The rail plate fits into the recess while its depending ribs fit into the grooves, thereby anchoring the plate to the tie and preventing lateral movement. Connection of the tie plate to the tie is provided by wood screws, while spikes secure the rail to the plate. In both of these patents, the depending rib provides additional lateral support to the plate, preventing it from moving sideways on the tie when a train passes. However, the linear shape and straight orientation of the ribs and grooves relative to the tie does not do anything to restrict longitudinal movement of the rail plate on the tie.
U.S. Pat. No. 3,957,201 to Johnson shows a concrete tie having an anchor structure set into a recess and a rail seat formed by base plate. A rail plate pad is located between the anchor and the rail. A threaded stud is attached to the underside of plate, preferably by spot welding, presumably to anchor the anchor structure into the body of the concrete tie. The threaded stud is permanently attached (welding being the preferred method) and evidently intended to be completely embedded and not accessible for repairs or replacement.
U.S. Pat. No. 4,925,094 to Buekett similarly discloses a concrete tie with a cast-in rail plate defining a rail seat, with downwardly projecting lugs embedded in the tie body. The lugs are provided to ensure a mechanical connection between the plate and the tie. Again, due to the nature of the tie and the connection with the lugs, removal of the rail plate for replacement or repair is not feasible.
U.S. Pat. No. 8,625,878 to Haas et al. describes an inspection system for a railway track that uses vision technology to read and compare a configuration of rail components with safety requirements stored in an associated processor. Similarly, U.S. Pat. No. 9,441,956 to Kainer et al. discloses a tie inspection system that uses a generated light to produce an image of the tie in order to compare it with stored parameters. U.S. Pub. No. 2012/0192756 to Miller et al. discloses a vision-based inspection system mounted on a railcar or other vehicle. However, all of these systems are relatively complex and require computer processing resources, along with the associated time and cost limitations. A visual inspection to ensure that the rail components are in place is a simpler and less expensive alternative.
It is therefore an object of this invention to provide a tie and a rail fastening assembly that overcomes the foregoing deficiencies.
It is a further object of the invention to provide a fastening system that does not require traditional insulators between the rail and clip, yet still provides rail-to-rail electrical isolation.
It is further an object of the invention to provide a system wherein lateral and longitudinal forces of passing trains are transmitted from the rail into the tie, not into the plate-to-tie fastening system. Although concrete ties historically do not use rail plates between the rail and the tie, the use of a plate will significantly reduce or even eliminate rail seat deterioration as it reduces the stresses that pass from the rail base into the concrete. Using a rail plate significantly increases the contact area (plate to concrete tie) as compared to the contact area of a rail base directly on the concrete tie, thus helping to spread the forces from the rail plate over a larger area of the tie and therefore reducing or eliminating abrasion of the concrete.
It is a further object of the invention to provide a system in which alternate fastening systems may be employed simply by changing the rail plate, rather than the tie.
It is a further object of the invention to provide a plate-to-tie fastening system that requires only a minor amount of clamping or connecting force; however, if a fastener is used, a single fastener may be all that is required to provide the needed force to retain the tie plate on the tie. Additional means may be used to prevent loosening of the fastener.
It is a further object of the invention to provide a fastening system located to protect it from damage, for example during a derailment.
It is a further object of the invention to provide a rail plate and rail pad that facilitate inspection of the assembly in place on a tie, when used together.
It is yet a further object of the invention to provide a mechanism to allow easy verification of whether the fastening system is properly retaining the plate and rail on the tie.
These and other objects of the invention will be better understood by reference to the detailed description of the preferred embodiment which follows. Note that the objects referred to above are statements of what motivated the invention rather than promises. Not all of the objects are necessarily met by all embodiments of the invention described below or by the invention defined by each of the claims.
The invention comprises a fastening system, to hold rails down on a concrete tie. A keyway, which preferably has a non-linear shape, is provided under each rail, across the width of the tie. The keyway is preferably narrower than the width of the rail base and accommodates a rail plate, which has a lower surface comprising a depending portion shaped to fit into the keyway in the tie, thus holding the rail plate and rail in place on the tie, while transmitting lateral and longitudinal forces from a passing train down into the tie, rather than into the rail and rail base alone. The bulk of the rail plate does not fit into the keyway, instead having an upper surface comprising a recess bounded by a pair of shoulders shaped to hold the rail base and to support a pair of rail clips that will hold the rail to the rail plate. Neither the rail clips nor the rail shoulders are therefore in direct contact with the tie.
A rail plate pad is provided between the rail plate and the tie surface, lining the inner surfaces of the keyway as well as the upper surface of the tie underneath the rail plate, to protect the tie from abrasion, to dissipate loads and to provide shock absorption. The pad thickness, hardness, internal geometry (shape factor) and other properties may be selected to provide desired track deflection, vertically and laterally, without the need to adjust the tie recess, tie size or other components of the assembly.
Due to the shape of the keyway, it is possible to simply place the rail plate pad and rail plate within the keyway and omit attachment means, while still sufficiently restraining lateral and longitudinal movement of the tie plate on the tie. As this may allow separation of the tie from the plate, an alternative embodiment includes one or more bolt holes within the keyway to accommodate bolts that pass from the rail plate and through the rail plate pad into the tie. The bolt heads may be covered or capped for security and to prevent them from contacting the underside of the rail base. The bolt cover may be keyed, to prevent or minimize loosening of the bolt. The bolt cover may cover the heads of individual fasteners, or may cover most or all of the rail seat. A gauge adjusting mechanism may be provided as part of the bolt cap. The positioning of the bolts under the rail provides an extremely protected area in which the bolts will not be damaged in case of a derailment, which can simplify recovery efforts, making it faster and easier to get a section of track back into operation after a derailment.
In another embodiment, similar protection against derailment damage may be provided for attachment means located on top of the tie plate and outside of the rail base.
In another aspect of the invention, the rail plate and the rail plate pad may be provided with an inspection mechanism, which allows an observer to quickly determine whether the fasteners are sufficiently retaining the rail plate in the correct position on the upper surface of the tie.
In one aspect, the invention comprises a railway tie having an upper surface to support a rail crossing a longitudinal axis of the tie, comprising at least one keyway in the upper surface wherein the keyway provides support to the rail to restrain the rail from moving along the longitudinal axis and transverse the longitudinal axis. The keyway comprises at least one edge or a plurality of edges, and the edge or at least one of the edges is not perpendicular to the longitudinal axis. The keyway may be shaped like an hourglass.
In a further aspect, the railway tie may comprise a fastening assembly to secure the rail to the tie, the fastening assembly comprising a rail plate having an upper surface and an opposed lower surface; shoulders on the rail plate upper surface to define a rail seat therebetween, the rail seat being configured to accommodate a base of the rail; and at least one recess within the rail seat to accommodate a fastener configured to secure the rail plate to the tie. A cap may be provided, the cap configured to fit within the recess; cover an upper portion of the fastener; and sit at least partially co-planar with or below the rail seat. The cap may itself comprise a recess to accommodate the upper portion of the fastener. The cap recess may be non-circular.
In a further aspect, the rail plate may comprise a protrusion on the lower surface, the protrusion being shaped and sized to fit within the keyway.
In yet a further aspect, the assembly may be provided with a rail pad configured to rest between the lower surface of the rail plate and the keyway.
In yet a further aspect, the assembly may be provided with a rail plate pad configured to rest between the rail seat and the rail. An underside of the rail plate pad may comprise at least one protrusion configured to fit within the recess and to cover an upper portion of the fastener. The protrusion may comprise a recess to accommodate the upper portion of the fastener. The protrusion recess may be non-circular.
In yet a further aspect, the railway tie may further comprise an inspection apparatus to indicate whether the rail plate is secured to the railway tie, the apparatus comprising at least one protrusion on an upper surface of the tie; and at least one aperture on the rail plate, the aperture being aligned with the protrusion such that alignment of the rail plate and the keyway allows the protrusion to extend through the rail plate aperture and be visible above the upper surface of the rail plate; wherein misalignment of the rail plate and the keyway will result in the protrusion receding from the rail plate aperture. The protrusion may be cast as part of the upper surface of the tie, or may be anchored into the upper surface of the tie. In a further aspect, the inspection mechanism may comprise an elongated pin configured to fit through an eye in the protrusion and to extend at least partially across the tie; the pin being further configured to break when the misalignment causes the protrusion to recede from the aperture; and the pin comprising at least one extension configured to be visible in a first position outside the rail plate when the pin is intact, and being further configured to move to a second position when the pin breaks. The protrusion and the aperture may be located within a recess in the rail plate. The recess may be located under a rail seat of the rail plate.
In another aspect, the invention may comprise a fastening assembly for a railway tie to secure a rail to the tie, the fastening assembly comprising a rail plate having an upper surface and an opposed lower surface; shoulders on the rail plate upper surface to define a rail seat therebetween, the rail seat being configured to accommodate a base of the rail and the shoulders being configured to accommodate rail fasteners to hold the rail in the rail seat; at least one recess within the rail plate, either within the rail seat or elsewhere on the rail plate, to accommodate a fastener configured to secure the rail plate to the tie; and a cover configured to overlay an upper portion of the fastener.
In a further aspect, the cover may comprise a cap configured to fit within the recess and to sit at least partially co-planar with or below the upper surface of the rail plate. The cap may comprise a recess to accommodate the upper portion of the fastener. The cap recess may be non-circular. Instead or in addition, the recess and the cap may be non-circular.
In a further aspect, the cover may comprise at least one protrusion from an underside of a rail plate pad configured to rest between the rail seat and the rail. The protrusion may comprise a recess to accommodate the upper portion of the fastener. The recess in the rail plate pad protrusion may be non-circular.
In yet a further aspect, the cover may comprise a cap configured to fit within the recess and to sit at least partially co-planar with or below the upper surface of the rail seat. The cap may comprise a recess to accommodate the upper portion of the fastener. The cap recess may be non-circular. Instead or in addition, the recess and the cap may be non-circular.
In yet a further aspect, the assembly may be provided with a rail pad configured to rest between the lower surface of the rail plate and the keyway.
In yet a further aspect, the assembly may be provided with a rail plate pad configured to rest between the rail seat and the rail.
In yet a further aspect, the assembly may be provided with an inspection apparatus to indicate whether the rail plate is secured to the railway tie, the apparatus comprising: at least one protrusion on an upper surface of the tie; and at least one aperture on the rail plate, the aperture being aligned with the protrusion such that installation of the rail plate on the tie allows the protrusion to extend through the rail plate aperture and be visible above the upper surface of the rail plate; wherein misalignment the rail plate on the tie will result in the protrusion receding from the rail plate aperture. The protrusion may be cast as part of the upper surface of the tie, or may be anchored into the upper surface of the tie. The inspection mechanism may further comprise an elongated pin configured to fit through an eye in the protrusion and to extend at least partially across the tie; the pin being further configured to break when the misalignment causes the protrusion to recede from the aperture; and the pin comprising at least one extension configured to be visible in a first position outside the rail plate when the pin is intact, and being further configured to move to a second position when the pin breaks. The protrusion and the aperture may be located within a recess in the rail plate. The recess may be located under a rail seat of the rail plate.
In a further aspect, the rail plate may comprise a protrusion on the lower surface, the protrusion being shaped and sized to fit within a keyway on an upper surface of the tie.
In another aspect, the invention comprises an inspection apparatus to indicate whether a rail plate is secured to a railway tie, the apparatus comprising at least one aperture on the rail plate, the aperture being aligned with the protrusion such that installation of the rail plate and the rail plate pad on the tie allows the protrusion to extend through the aperture and be visible above an upper surface of the rail plate; wherein misalignment of the rail plate and the tie will result in the protrusion receding from the aperture. The protrusion may be cast as part of the upper surface of the tie, or may be anchored into the upper surface of the tie. The inspection apparatus may further comprise a rail plate pad configured to fit between the rail plate and the tie. The rail plate pad may further comprise at least one aperture aligned with the rail plate aperture and adapted to accommodate the tie protrusion.
In a further aspect, the inspection mechanism may further comprise an elongated pin configured to fit through an eye in the at least one protrusion and to extend at least partially across the tie; the pin being further configured to break when the misalignment causes the protrusion to recede from the aperture; and the pin comprising at least one extension configured to be visible in a first position outside the rail plate when the pin is intact, and being further configured to move to a second position when the pin breaks. The protrusion and the aperture may be located within a recess in the rail plate. The recess may be located under a rail seat of the rail plate.
The foregoing may cover only some of the aspects of the invention. Other aspects of the invention may be appreciated by reference to the following description of at least one preferred mode for carrying out the invention in terms of one or more examples. The following mode(s) for carrying out the invention is not a definition of the invention itself, but is only an example that embodies the inventive features of the invention.
At least one mode for carrying out the invention in terms of one or more examples will be described by reference to the drawings thereof in which:
As best seen in
The rail plate 14 comprises a rail seat 16 to accommodate the base of rail 12. The rail plate is defined by shoulders 18, which retain rail fasteners, such as clips 20, to hold the base of the rail 12 to the rail plate 14. Shoulders 18 also serve to provide a bearing surface for the edge of rail to bear against, thereby providing gauge restraint. It will be evident that the rail plate 14 carries the means to retain the rail fasteners, avoiding the need to use concrete ties having cast-in shoulders or other inserts, along with specific rail fasteners to match those inserts. The invention therefore provides flexibility, as the type of fastener used can be changed simply by using a different rail plate 14, which can therefore accommodate different rail sizes. Essentially, the tie is “generic”, instead of being restricted to the particular type of elastic clip associated with the clip-receiving shoulders or inserts that are cast into the tie. If it is desired to use a different elastic clip, it is possible to merely change out the plates to obtain clip receiving systems compatible with the new preferred clips, rather than having to change the entire tie. The shoulders 18 and associated rail fasteners illustrated are exemplary; several rail fasteners are known and may suitably be used, such as resilient clips driven longitudinal to the rail, resilient clips driven perpendicular to the rail, and resilient clips tensioned via screws or bolts. Production of the tie may also be simpler, as it can be made without worrying about proper insertion of various cast-in shoulders or other inserts for various clip systems. In addition, damaged clip retainers may be repaired or replaced simply by replacing the plate, rather than requiring an entirely new tie.
Cushioning means, such as rail plate pad 22 may be provided between the rail plate 14 and the tie 10. The thickness, hardness, geometry and other properties of rail plate pad 22 may be selected to provide desired track deflection, vertically and laterally.
As best seen in
Referring now to
The shape of the keyway may therefore alone provide adequate support to sufficiently limit movement of the rail plate 14 and rail 12 relative to the tie 10. It will be understood that there is some resiliency offered by the plate pad 22 that will allow plate lateral and longitudinal deflection under load. This may allow a concrete tie to behave in a manner similar to wood or may simply offer more resiliency against vibration and also to help distribute the load amongst more ties. In the case of loss of under-tie support, however, additional security is provided to ensure the retention of rail plate 14 on tie 10 through the use of one or more removably secured plate-to-tie fasteners, such as bolts 34. In the embodiment shown in
It can be seen that in this embodiment, any fasteners 34 holding the rail plate 14 and rail plate pad 22 in place on the tie 10 are substantially protected from damage that might be caused, for example, by a train wheel during a derailment. Further protection of the plate-to-tie fasteners 34 may be provided by one or more caps 42, which fit over the top or heads 48 of the plate fasteners 34. The recesses 32 are preferably sized to allow the heads 48 of plate fasteners 34 to lie below the upper surface 50 of the rail seat 16, such that the upper surface 52 of caps 42 is either co-planar with the upper surface 50 or is slightly recessed. This arrangement allows the rail 12 to sit securely within rail seat 16 while still protecting the heads 48 of plate fasteners 34. As can be seen in
A second embodiment of the invention is shown in
In this embodiment, rail plate 14 is provided with shoulders 18 shaped to accommodate a different type of rail fastener, in this case an e-clip 120. Again, this type of shoulder and rail fastener are exemplary; because the plate is changeable, any suitable rail fasteners may be used, including those that can be driven in a direction perpendicular to the rail, longitudinal to the rail or using tension. Again, the rail fasteners may instead be mounted directly on the upper surface 26 of the tie 10, outside of the rail plate 14, as long as they apply sufficient force to hold the base of the rail 12 to the tie.
Rail seat pad 56 may have an upper surface 62 that is substantially flat, or may be provided with one or more raised edges 64. Edges 64 assist with electrical insulation between the rail 12 and the rail plate 14. Edges 64 may be provided in different thicknesses, allowing some amount of gauge adjustability, which can help simplify installation of the rail 12 on the tie 10.
Instead of or in addition to providing one or more plate fasteners 34 located under the rail seat, plate fasteners 34 may be located outside of the rail seat 16, as shown in
An inspection mechanism, best shown in
In the foregoing description, exemplary modes for carrying out the invention in terms of examples have been described. However, the scope of the claims should not be limited by those examples, but should be given the broadest interpretation consistent with the description as a whole. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.
