Patent Publication Number: US-9850624-B2

Title: Mobile automated tie replacement system

Description:
COPYRIGHT 
     A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. 
     TECHNICAL FIELD 
     The present invention relates generally to railroad maintenance equipment, and, more particularly, to equipment for changing ties of a railroad. 
     BACKGROUND 
     As is well known, railroads are based on trains running on parallel metal rails. The rail road includes flat-bottom steel rails supported on timber crossties that are perpendicular to the rails. The ties are laid on crushed stone ballast. Each rail is placed on a tie plate disposed between the crosstie and the rail. The rail is held down to the crosstie with spikes that are driven through the tie plate to the crosstie. Additional tie anchors may be used to join the rail to the crosstie. The crosstie transfers the loads from the rails to the ballast and the ground underneath and holds the rails to the correct gauge. Typically, crossties are timber treated with creosote, copper-chrome-arsenic, or other wood preservative. The purpose of the ballast is to support the ties and allow some adjustment of their position, while allowing free drainage. 
     Railroads require periodic maintenance and replacement of worn out components such as crossties. For example, the crossties must be periodically inspected and replaced to maintain the rail gauge as well as insure the track transfers load. Replacement of crossties therefore must be performed quickly with a minimal amount of disturbance to the rails. 
     Currently, replacement of ties involves a tie gang that is a long series of machines that together march along the track, replacing bad crossties with new ones. From front to back, a tie gang includes machine operators to operate a sequence of machines such as spike pullers, spike reclaimers, tie cranes, tie extractor(s), anchor spreaders, tie cranes, tie inserters, tampers, plate placers, spike drivers, and surfacing machines to tamp the track and groom the ballast. There are also numerous workers on foot, handling tie plates and dealing with anomalies that come up where the machines have trouble. Old ties are marked with paint ahead of a tie gang, so the workers know which ties are to be replaced. New ties are typically distributed in bunches by another set of machines. Typically, this is done with a standard excavator running on top of a series of gondolas to bring the bunches of new ties near the rails. Near the front of the tie gang, a tie crane is used to distribute the bunches of ties so that a new tie is positioned next to each old tie that is to be replaced. 
     Currently, a “conventional” tie changing machine is used that operates by extracting ties with a mechanical arm while the rails are lifted above the tie to be pulled out. An example of a conventional tie changing machine is the TR-10 Tie Exchanger manufactured by Harsco Rail of Columbia, S.C. In order for the TR-10 to function, the spikes or clips must first be removed from the tie that is to be replaced. The conventional tie changing machine such as the TR-10 discards the tie plates and therefore requires a worker to manually pick up the tie plates and reposition them before the new ties may be inserted. 
     Following the tie removal, other, separate machines are used to spread the anchors and carefully position a new tie in line with the open crib. Additional conventional tie changing machines such as the TR-10 are used to insert the new ties. The inserters are followed by a tamping machine, additional laborers who reposition the tie plates on the new tie, and finally a plate inserter/rail lifter that slides the tie plates into their final position. 
     Thus, there is a need for a combined tie changing machine that can simultaneously hold the tie plates, spread the anchors, pull out the old tie, and insert a new tie, to save labor and machine costs. There is a further need for a tie changing machine having a similar construction as to existing excavators in order to facilitate the tie changing operation. There is a further need for a tie changing machine that is self-propelled and may remove ties from either side of a set of rails. 
     SUMMARY 
     According to one example, a railroad tie changing machine for replacing a railroad tie is disclosed. The railroad tie extends laterally under two rails and is attached to the two rails via tie plates. The tie changing machine includes a tie changing boom moveable to one side of the two rails. The tie changing boom includes a gripping assembly for clamping the railroad tie. The tie changing boom is moveable between a proximate position and a distal position from the one side of the two rails to grip the tie and remove it from under the two rails. The tie changing machine includes a kicker located on the opposite side of the rails from the tie changing boom. The kicker is moveable to contact one end of the tie to move the tie toward the tie changing boom. The tie changing machine includes a pair of track jacks to raise the tracks at a location proximate to the tie. The tie changing machine includes a pair of tie plate clamps to hold the tie plates in place when the kicker moves the tie. 
     Another example is a method of replacing an old railroad tie mounted under two rails via tie plates using a tie changing machine including a tie gripper assembly, a tie plate clamp assembly, and a kicker assembly. The tie plates are clamped in place over the old railroad tie with the tie plate clamping assembly. The rails are jacked up. The tie gripper assembly is moved in proximity to one end of the old railroad tie via a boom arm from one lateral end of the track. The opposite end of the old railroad tie is pushed via a kicker assembly. One end of the old railroad tie is gripped via the gripper assembly. The boom assembly is moved to remove the old railroad tie from under the rails. One end of a new railroad tie is gripped via the gripper assembly. The boom assembly is moved to insert the new railroad tie in position under the rails. 
     Additional aspects of the invention will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments, which is made with reference to the drawings, a brief description of which is provided below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view of an example self-propelled tie changing machine; 
         FIG. 1B  is a perspective view of the self-propelled tie changing machine in  FIG. 1A  gripping a railroad tie; 
         FIG. 1C  is a perspective, opposite side view of the tie changing machine in  FIG. 1A  gripping a railroad tie; 
         FIG. 2  is a cross-section view of the tie changing machine in  FIG. 1A  showing detailed actuation components; 
         FIG. 3A  is a close-up perspective view of the plate/rail gripping assemblies in the tie changing machine in  FIG. 1 ; 
         FIG. 3B  is a side-view of one of the plate/rail gripping assemblies of the tie changing machine in  FIG. 1 ; 
         FIG. 4  is a perspective view of the tie gripping assembly of the tie changing machine in  FIG. 1 ; 
         FIG. 5A-5E  is a sequence showing the process of removal of a railroad tie using the tie changing machine shown in  FIGS. 1A-1C ; and 
         FIG. 6A-6B  are perspective views of the tie changing machine shown in  FIGS. 1A-1C  inserting a new railroad tie. 
     
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
       FIG. 1A-1C  show perspective views of a self-propelled tie changing machine  100 . The tie changing machine  100  includes a railway chassis  102  that is mounted on sets of wheels  104  and  106 . The tie changing machine  100  may therefore be moved via rail. The chassis  102  includes a pair of indentations  108 . The indentations  108  each mount a rail/plate clamp assembly  110  and  112 . The chassis  102  also includes a railway engine compartment  114 , a hydraulic reservoir  116 , and a fuel tank  118 . The railway engine compartment  114  contains a drive engine that allows propulsion of the chassis  102  along the rails. The engine in the engine compartment  114  also powers the hydraulics of the rail/plate clamp assemblies  110  and  112 . As may be seen in  FIG. 1A , the tie changing machine  100  is propelled on the wheels  104  and  106  by the drive engine on railroad tracks to the locations where ties need replacement. Of course, the tie changing machine  100  may also be towed to the desired location and therefore may not require the drive engine. 
     The tie changing machine  100  also includes an operator cabin  120  and engine housing  122 . The engine housing  122  includes an engine, which powers the hydraulic systems of the tie changing components of tie changing machine  100  as explained below. The engine housing  122  and operator cabin  120  are mounted on a rotatable platform  124 , which is mounted on a base  126  that is mounted on the chassis  102 . 
     As may be seen in  FIGS. 1B and 1C , the rotatable platform  124  may be swiveled to an operational position when the tie changing machine  100  operates to replace ties on the track. The dual rail/plate clamp assemblies  110  and  112  perform the functions of jacking up rails at the position that a tie should be replaced. The rail/plate clamp assemblies  110  and  112  also include plate clamps used to clamp the tie plates supporting both rails once they are detached from the ties and spread the front and rear anchors on both of the rails as will be explained below. This process frees the tie from the tie plates and the anchors and allows the tie to be moved out from under the rails. 
     The tie changing machine  100  includes a kicker assembly  130  mounted on the engine housing  122  near one end of the rotatable platform  124  and a tie changing assembly  140  mounted on the opposite end of the rotatable platform  124 . The kicker assembly  130  includes a swinging arm  132  that has one end rotatably attached to the bottom of the engine housing  122 . The opposite end of the swinging arm  132  is attached to a cross member  134 . The cross member  134  is substantially perpendicular to the swinging arm  132 . The cross member  134  has one end that includes a contact plate  136  that has a surface area approximately the size of the end of a cross tie. The kicker assembly  130  includes a stabilization plate  138  that joins the cross member  134  to the swinging arm  132 . 
     The kicker assembly  130  is hydraulically propelled between an up position where the swinging arm  132  is rotated to a position roughly parallel to the chassis  102  as shown in  FIG. 1B . When the rotating platform  124  is swiveled to the operational position shown in  FIG. 1C , the swinging arm  132  may be rotated from the up position to a down position perpendicular to the chassis  102 . As will be explained below, the swinging motion by the arm  132  propels a tie in the direction toward the tie changing assembly  140 . 
     The tie changing assembly  140  includes a mounting plate  142 , which is attached to the top of the rotating platform  124 . The mounting plate  142  includes two support walls  144  and  146  that support the rotation of one end of a boom  148 . The boom  148  is articulated and has a first end  150  that is pivotably mounted to the support walls  144  and  146 . The first end  150  is part of a main support  152 , which is attached to an articulated secondary support  154 . The boom  148  includes parallel supports  156  and  158 . 
     An opposite end  160  of the boom  148  supports a gripping arm  162 , which is pivotably mounted on an axis  164  supported by the opposite end  160  of the secondary support  154 . The gripping arm  162  includes two parallel supports that pivot around the axis  164 . 
     An end  170  of the gripping arm  162  mounts a tie gripping assembly  180 . The tie gripping assembly  180  includes two clamp arms  182  and  184 , which clamp onto opposite sides of a railroad cross tie  186  as shown in  FIGS. 1B and 1C . 
       FIG. 2  is a cross section of the tie changing machine  100  showing the hydraulic actuation system and additional operational components. The hydraulic actuation system includes a pump powered by the engine located in the engine housing  122 . Hydraulic fluid may be stored in the hydraulic fluid reservoir  116  shown in  FIG. 1A . The hydraulic actuation system is controlled by the operator in the operator cab  120 . The kicker assembly  130  is actuated by a main hydraulic cylinder  202 . One end of the cylinder  202  is coupled to a pivot point  204 , which is mounted on the upper part of a back wall  206  of the engine housing  122 . The other end of the cylinder  202  is attached to a rotatable mounting point  208  on a translation linkage  210 . The translation linkage  210  has a first arm  212 , which is coupled to the rotatable mounting point  208 . A central arm  214  is rotatably connected to a pivot point  216  that is mounted near the bottom of the back wall  206 . A second arm  218  holds a pivot that is rotatably coupled to a linkage  220 . The other end of the linkage  220  is pivotably coupled to the swinging arm  132  of the kicker assembly  130 . 
     When the main cylinder  202  is retracted, it pulls the arm  212  and pivots the translation linkage  210  around the pivot point  216  in a clockwise direction. When the main cylinder  202  is extended, it propels the translation linkage  210  in a counter clockwise direction and pushes the linkage  222  to rotate the swinging arm  132  of the kicker assembly  130  down. 
     As will be explained below, the tie changing assembly  140  operates in a similar fashion as a construction excavator. The tie changing assembly  140  includes a pair of boom cylinders  250  that each have a first end pivotably coupled to the mounting plate  142 . The second ends of the boom cylinders  250  are mounted on pivot point  254  on the main support  152  of the boom  148 . A top arm cylinder  260  has a proximal end pivotably attached to a pivot point  262  on the top of the gripping arm  162 . The opposite, distal end of the top arm cylinder  260  is pivotably attached to the end of the gripping arm  162 . A bottom arm cylinder  270  has a proximal end pivotably attached to a link member  272  on the bottom of the boom  148 . The opposite, distal end of the bottom arm cylinder  270  is attached to the middle of the gripping arm  162 . The arm cylinders  260  and  270  work in concert to provide additional force to rotate the arm  162 . 
     The boom cylinders  250  may be extended to raise the boom  148  and gripper assembly  180  and may be retracted to lower the boom  148  and the tie gripping assembly  180 . The top cylinder  260  and bottom cylinder  270  work in a complementary fashion to rotate the griping arm  162  around the end of the boom  148 . The gripping arm  162  may be rotated away from the chassis  102  by retracting the top arm cylinder  260  and extending the bottom arm cylinder  270 , causing the gripping arm  162  to rotate around the end of the boom  148 . The gripping arm  162  may be rotated toward the chassis  102  by extending the top arm cylinder  260  and retracting the bottom arm cylinder  270 . This causes the end of the gripping arm  162  attached to the tie gripping assembly  180  to be brought near the rail and ties. 
     A gripper cylinder  280  is attached between the gripping arm  162  and a linkage  282 . The linkage  282  pivots on the arm  162  and has a rotating member  284  attached to the gripping assembly  180 . The gripper cylinder  280  allows the gripping assembly  180  to be tilted in relation to a tie. 
     A ballast broom and tie guide attachment  290  is installed at the bottom of the chassis  102  between the rail/plate clamp assemblies  110  and  112 . The attachment  290  may be rotated into place so that a series of brooms  292  may contact the top of the ties and brush away stray ballast on the ties. A tie guide  294  assists in insuring that a new tie is inserted in proper alignment with the tie plates and the rails as will be explained below. 
       FIG. 3A  is a close-up perspective view of the rail/plate clamp assemblies  110  and  112  of the machine  100  in  FIG. 1 .  FIG. 3B  is a side view of components of the rail/plate clamp assembly  110  of the machine in  FIG. 1 . The rail/plate clamp assemblies  110  and  112  hold the plates from a tie, spread the anchors, and clamp onto the rails to jack up the rails so the tie changing assembly  140  may remove the tie. As shown in  FIG. 3A , the rail/plate clamp assembly  110  includes a support frame  302 . The support frame  302  is not shown in  FIG. 3B  to better show the rest of the components. The support frame  302  holds a front guide wheel  304 , a front track gripping assembly  306 , a front jack assembly  308 , a tie plate gripping assembly  310 , a rear jack assembly  312 , a rear track gripping assembly  314  and a rear guide wheel  316 . The other track jacking assembly  112  includes similar components. The front guide wheel  304  and the rear guide wheel  316  rotate on the track to provide additional stability. 
     The support frame  302  is coupled to the corresponding support frame of the rail/plate clamping assembly  112  by a cross frame bar  318 . The front track gripping assembly  306  includes a cylinder  320  that powers a pair of articulating clamp arms  322  and  324  that grip the rail on one side of the tie. The rear track gripping assembly  306  includes a cylinder  330  that powers a pair of articulating clamp arms  332  and  334  that grip the rail on the opposite side of the tie. Once the clamp arms  322  and  324  and  332  and  334  grip the rails, hydraulic jacks at the bottom of the chassis  102  activate to lift the frame  302  and the rails that are held by the clamp arms  332  and  324 . 
     The tie plate gripping assembly  310  includes a horizontal cylinder  350  that allows actuation and rotation of two grip arms  352  and  354 . The grip arms  352  and  354  are attached to one end of a respective two curved pivot bars  360  and  362 . The other end of the pivot bars  360  and  362  are rotatably attached to a rotating cam  364  to join the actions of the arms  352  and  354 . When the horizontal cylinder  350  is extended, the grip arm  354  is moved in a counter-clockwise direction and through the pivot bars  360  and  362  rotates the other grip arm  352  in a clockwise direction. This action closes the grip arms  352  and  354  to grip the tie plate. When cylinder  350  is retracted, the grip arms  352  and  354  move apart and release the tie plate. 
     A lateral cylinder  370  allows the spreading of anchors on the tie. The cylinder  370  in this example is a dual cylinder arrangement that moves a sliding frame  372  forward and backward on a lateral track  374 . The tie plate gripping assembly  310  is mounted on the sliding frame  372 . Either end of the cylinder  370  may be extended. When both ends of the cylinder  350  are extended, the plate gripping assembly  310  moves to the forward position, sliding a front anchor away from the tie via the tie plate held by the grip arms  352  and  354 . When both ends of the cylinder  370  are retracted, the plate clamp assembly  310  moves to the rear position, sliding the rear anchor away from the tie via the tie plate held by the grip arms  352  and  354 . A pair of vertical cylinders  340  and  342  are retracted in order to move the plate gripped by the grip arms  352  and  354  up and hold it over the tie to be replaced. When the vertical cylinders  340  and  342  are extended, the plate is moved back to rest on the new tie. 
       FIG. 4  is a close-up perspective view of an example tie gripping assembly  180  of the machine  100  in  FIG. 1 . The tie gripping assembly  180  includes the two clamp arms  182  and  184 . The clamp arms  182  and  184  each have a respective contact plate  402  and  404  that contact the sides of the tie. The clamp arms  182  and  184  are rotatably attached to a clamp cylinder  410 . The clamp arms  182  and  184  rotate on pivots attached to the ends of a front horizontal frame member  412  and a rear horizontal frame member  414 . The rotating member  284  is attached to the arm  162  as shown in  FIG. 2 . The rotating member  284  includes a support plate  420  that supports a rotary actuator  422 . The bottom of the rotary actuator  422  is attached to a grip support plate  424  that is attached to the horizontal members  412  and  414 . The rotary actuator  422  rotates the grip support plate  424  and therefore the clamp arms  182  and  184 . This rotation gives the tie gripping assembly  180  one additional degree of freedom. As explained above, the clamp arms  182  and  184  may be tilted by actuating the gripper cylinder  280  in  FIG. 2  that rotates the rotating member  284  and therefore moves a gripped tie toward or away from the rails. The actuator  424  may be rotated to position a gripped tie more accurately side to side in relation to the rails. 
       FIGS. 5A-5E and 6A-6C  are side and perspective views of the tie changing machine  100  operating to replace a railroad tie. The tie changing machine  100  is driven into position on rails  502  and  504  to the location on the track where the tie is to be replaced. As in normal operation, fresh ties such as a new tie  510  are dropped to the side of the approximate location of the tie to be replaced. A spike puller is used to pull the spikes out of the tie plates holding the rails  502  and  504  to an old tie  512 . The platform  124  is rotated so the kicker assembly  130  and tie changing assembly  140  are parallel to the ties as shown in  FIG. 5A . The kicker assembly  130  is initially in the up position. The tie changing assembly  140  swings the boom  148  down in proximity to one end of the tie  512 . The tie changing assembly  140  engages the old tie  512  but does not engage the clamp arms  182  and  184  of the tie gripping assembly  180  on the tie  512 . The plate clamp assembly  310  for each of the rail/plate clamp assemblies  110  and  112  actuate the gripping arms  352  and  354  to engage the tie plates on both ends of the old tie  512  and hold them in place. The plate is lifted by the tie plate gripping assembly  310  to be clear of the old tie  512 . The anchors are spread from the old tie  512  by the forward and rear actuation of the cylinder  350  in  FIG. 3 . The rail clamps  322  and  324  and  332  and  334  of the rail/plate clamp assemblies  110  and  112  in  FIGS. 3A-3B  engage the rails  502  and  504 . The hydraulic jacks extend and raise the rails  502  and  504  up at the location of the old tie  512  to relieve pressure on the tie  512  to be pulled. 
     As shown in  FIG. 5B , the kicker assembly  130  is activated and the swinging motion of the swinging arm  132  causes the contact plate  136  to hit the opposite end of the old tie  512  from the tie gripping assembly  180 . The old tie  512  is thus moved toward the tie gripping assembly  180  as shown in  FIG. 5C . The plates are held in place by the rail/plate clamp assemblies  110  and  112 , and the tie  512  may move because the rails  502  and  504  have been jacked up. The clamp arms  182  and  184  of the tie gripping assembly  180  then clamp on to the old tie  512 . 
     As shown in  FIG. 5D , the kicker assembly  130  is then moved to the up position and clear of the tie location. The tie gripping assembly  180  is moved outward by the combined movement of the boom cylinders  250  and the arm cylinders  260  and  270  to extract the old tie  512  that is gripped by the tie gripping assembly  180 . As shown in  FIG. 5E  and  FIG. 6A , once the old tie  512  is extracted from under the rails  502  and  504 , it is released by the tie gripping assembly  180  and discarded. The tie changing assembly  140  is moved over the new tie  510  and the clamp arms  182  and  184  of the tie gripping assembly  180  grip one end of the new tie  510 . The tie changing assembly  140  then aligns the new tie  510  with the open crib vacated by the old tie  512  by rotating the actuator  422 . 
     The tie guide and the ballast broom assembly  290  are moved down to align with the bottom of the tie plates as shown in  FIG. 6B . The ballast broom assembly  290  sweeps any stray ballast from the top of the ties. The tie changing assembly  140  retracts to insert the new tie  510  as shown in  FIG. 6A-6B . The kicker assembly  130  swings down the swinging arm  132  to provide an end stop in the form of the contact plate  136 . As shown in  FIG. 6B , the tie changing assembly  140  grips the new tie  510  and inserts it to the desired lateral position relative to the rails  502  and  504 . Although the above figures show the insertion of ties from one side of the tracks  502  and  504 , it is to be understood that the operation may be performed from the opposite side by rotating the platform  124  so the tie changing assembly  140  is placed over the opposite side of the track. 
     Once the new tie  510  is inserted in the desired position, the tie guide and ballast broom assembly  290  retract. The kicker assembly  130  is retracted to the up position. The jacks are retracted and the rail clamp arms  322  and  324  and  332  and  334  release the grip on the rails  502  and  504 . The rail/plate clamp assemblies  110  and  112  release and retract and thus the plates are placed in position on the new tie  510 . The boom  148  lifts into the clear. The machine  100  is then driven to the next tie to be replaced. The tie gang workers may thus reattach the plates to the new tie  510  by inserting spikes via a spiker machine. 
     The complete automation of the tie replacement process provides savings in labor that was previously required to retrieve the tie plates manually, place tie plates manually, and operate various specialized machines. The integrated tie changing machine  100  also saves the previous need for separate machines for removing the tie, spreading anchors, handling ties, and inserting tie plates. The concept of using the top half of a machine similar to an excavator mounted to the rail-bound chassis  102  has several benefits. By using excavator parts that are proven and mass-produced, the expectation is that the machine as a whole can be simpler, less costly to build, and easier to maintain. The combined plate-holding tie remover/inserter functions of the tie changing machine  100  have the benefit of eliminating several machines and manual laborers from a typical tie gang. Tie removal and insertion are done by the same machine as opposed to separate machines in a typical gang. By holding the plates, the machine  100  eliminates the manual labor involved with collecting plates and placing plates, as well as eliminating conventional plate inserter machine(s). By using the plate clamps to spread the anchors, the anchor spreaders used in a typical tie gang are eliminated. With greater flexibility to grab the new sleeper, the tie crane that typically operates between the remover and inserters is eliminated. 
     Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims.