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RELATED APPLICATIONS 
       [0001]    None 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    This invention pertains to a method and apparatus for repairing shoulders attached to railroad ties and used to hold rails in place, and more particularly, to a method in which a clip is attached to a face of the shoulder to compensate for material worn away by extended wear and tear. 
         [0004]    2. Description of the Prior Art 
         [0005]    Railroad systems are still used in many parts of the world as a primary means of transporting freight and people. In a typical modern railroad system, the rails are supported on concrete ties by a pad positioned between two iron shoulders. More specifically, a resilient pad is disposed between the shoulders on the ties, with plastic insulators being coupled to the pads and abutting each of the shoulders. The pads are resilient to protect the ties and to provide a smoother ride for the train and to compensate for slight size and position variations of the ties. As each of the wheels of a moving train passes over each of the ties, the weight of the train causes the rail to travel slightly downward on the pad, causing the sides of the plastic insulators to rub against a face of the shoulders. Over time, this action is repeated sufficiently to cause wear and te3836-018final.docar of the shoulder face. This erosion is increased when sand and other abrasive particles are lodged between the sides of the plastic insulator and the shoulder face. The same action also produces a wear and tear effect on the sides of the plastic insulators as well. The erosion of the shoulder face and the sides of the plastic insulators can be sufficiently large to allow the pad disposed between two adjacent shoulders, and the rail disposed therebetween to shift laterally. This lateral shift can be, in some instances, sufficiently large to cause the gauge to be too wide to meet the standard railroad specs. 
         [0006]    This problem must be corrected by eliminating the effects of wear and tear on the plastic insulators and the iron shoulders. Plastic insulators are designed to last as long as rail sections and therefore it is relatively easy and simple to replace the plastic insulators (and the pads, if necessary) at the same time as the rails. However, the iron shoulders are embedded into the concrete ties and cannot be removed therefrom. Therefore, until now, the only way to correct for excessive wear of a shoulder face is to replace the entire tie. Needlessly to say, replacing concrete ties is very expensive, and time consuming. In the present invention, an alternate means and method are provided to repair iron shoulders with worn front faces. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0007]      FIG. 1  is a somewhat diagrammatic plan view of a typical section of railroad track with several ties; 
           [0008]      FIG. 2  shows a plan view of a rail support used on the track of  FIG. 1  with a shim constructed in accordance with this invention; 
           [0009]      FIG. 3  shows an enlarged view of a shoulder receiving a shim in accordance with this invention; 
           [0010]      FIG. 4  shows the face of the shoulder used in  FIG. 3 ; 
           [0011]      FIG. 5  shows a front view of the shim being applied to the shoulder of  FIGS. 1-4 ; and 
           [0012]      FIG. 6  shows a flow chart of the present process. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    Referring first to  FIG. 1 , a typical railroad track  10  consists of a several ties  12  disposed on the grade along the track bed. Each tie holds two rail support assemblies  14 , for supporting two parallel rails  16 ,  18 . The rails  16 ,  18  are shown only in outline. Detail of the rails and many additional components such as clips securing the rails  16 ,  18  to the support assemblies  14 , and other well known components have been omitted for the sake of clarity. The ties can be made of concrete. Moreover, in some instances, rather then providing a single tie extending under both rails  16 ,  18 , individual tie segments may be used, with one tie segment being disposed under each rail. 
         [0014]    As shown in more detail in  FIG. 2 , each support assembly  14  includes two shoulders  20 . The shoulders  20  are made typically of iron and have one or two mounting legs (not shown) imbedded in the ties. 
         [0015]    The two shoulders  20  are carefully placed with respect to each other to define an exact space L between them. In addition, the two support assemblies  14  on each tie are carefully placed at an exact distance from each other to define the distance between the rails  16 ,  18  and thereby define the gauge of the track. 
         [0016]    A pad  22  having a general I shape is disposed between the shoulders  20  as shown. The pad is preferably made in one or more pieces and is resilient to provide cushioning for the rails. The pad  22  is preferably attached to the respective tie  12  using an appropriate adhesive. Pads of this type are disclosed for example in commonly assigned U.S. Pat. No. 7,080,791 incorporated herein by reference. Of course, other types of pads may be used as well. 
         [0017]    The pads  20  have two lateral cutouts that house corresponding insulators  24 . The insulators are made of an electrically insulating material and are provided to provide electrical isolation between the shoulders  20  and rails  16 ,  18 . The insulators  24  are normally attached to the pad  22  and are in contact with the front face  26  of the respective shoulder  20 . As a result, as discussed, each time a railroad wheel rolls over each pad  22 , the pad  22  gets compressed vertically causing a vertical movement of its insulators  24 . Since the insulators  24  are in physical contact with respective shoulders  20 , after a while they wear portions of the face  26  away and cause a gap ‘g’ to form between the face  26  and the respective insulator  26 . (See  FIG. 2 ). As discussed above, the positions of the shoulders  20  define the gauge of the track. Once gap g is formed, the pad  22  can creep laterally toward the shoulder thereby increasing the lateral spacing between the rails  16 ,  18  sufficiently so that this distance may exceed the nominal gauge of the track. However, until now the only way to overcome this problem was to replace the whole tie with a new tie and new shoulders. 
         [0018]    According to the present invention, a worn shoulder is repaired using a shim  30  sized to fit over its face, as indicated in  FIG. 2 . More particularly, as shown in  FIGS. 3 and 4 , a typical shoulder  20  is formed with a body  30  forming a horizontal platform  32  between two walls  34 ,  36  which are angled toward each other as they approach face  37 . The body  30  is also formed with two lateral wings  38 ,  40 . As previously discussed, the shoulder  20  also includes one or two legs (not shown) that extend downwardly and are set into the concrete tie for mounting the shoulder  20 . 
         [0019]    As shown in  FIGS. 1 and 2 , the face  37  comes into contact with an insulator  24  on pad  22 . Over time, as trains pass over the support  14 , the movement of the insulator  24  causes the face  37  to wear off. This action is further aggravated by sand, and other extraneous matter that collects between the face  37  and insulator  24  and act as an abrasive therebetween. 
         [0020]    In the embodiment shown, the shoulder  20  is formed with an upright extension  42  having a generally triangular cross-section. It should be understood that the shoulder described herein is just one of many different types of shoulders that are presently available from different manufacturers. Other shoulders may have slightly different shapes and sizes then what is shown herein. 
         [0021]    In order to resolve the worn shoulder problem, a shim  60  is provided. Preferably the shim is made of a thin steel plate having a uniform thickness, but can be made from other materials as well. The shim  60  is shaped to match the shape of shoulder front  37 . Typically the shim  60  may have a thickness of about 1/16-⅛ in. As shown in  FIGS. 3 and 5 , the shim  60  includes a body  62  formed of a straight central segment  64  and two lateral wings  66 . In the configuration shown in  FIG. 3  the face  37  has rounded sides  44 ,  46 , said sides being in the shape of a partial cylinder with a vertical axis of curvature. For this shoulder, the wings  66  are curved to match the curvature of sides  44 ,  46 , as shown. One or more tabs  68  are also provided which extend over the platform  32 . In the figures, two tabs  68  are provided, one on each side of extension  42 . However, if a shoulder does not have an extension, then a single tab  68  can be provided that is wide enough to extend across the width of the platform  32 , or three or more tabs  68  are used. 
         [0022]    The shim  60  is held in place by an industrial-strength epoxy or other strong adhesive material. Preferably, the epoxy must be weather proof since the track systems are frequently installed in locations that are subjected to inclement weather conditions with large temperature and humidity ranges. One such material is available under the name of SRP  210  or Spikefast Polyurethane available from Willamette Valley Company, Eugene, Oreg. Other adhesives may be used as well. 
         [0023]    In one embodiment of the invention, the shim  60  is applied in place using the epoxy to hold in place. However, a better practice is to remove the pad  22  before installing the shim  60 . This process is performed as illustrated in  FIG. 6 . In step  100  the clips (not shown) holding the rails  16 ,  18  are removed. In step  102  a portion of the rail ( 16  and/or  18 ) is cut and the cut rail portion is removed. In step  104  the supports  14  are removed, including the pads  22  and insulators  24  are removed. In step  106  the ties  12  and the shoulders  20  are thoroughly cleaned and dried, using a blow torch, if necessary. 
         [0024]    In step  108  all the worn shoulders are identified. In step  110  at each affected tie, a shim is provided and epoxy is deposited on the shim and the shim is attached to the shoulder (step  112 ). The amount of the epoxy  70  used (see  FIG. 3 ) can depend on the actual wear of the shoulder. Naturally, more epoxy  70  is used for shoulders with more wear. If necessary, the shims are heated to set the epoxy (step  114 ). Then in step  116  new pads and insulators are installed, if necessary, unless the old ones are good enough. As part of this step, a lubricant such as white lithium grease may be applied between the insulator  24  and the shoulder face  37  to reduce friction, retard mold formation, etc. In step  116  a new rail segment is positioned on the rail supports  14  and installed, clips are installed to hold the rail segment in place (step  120 ) and finally, in step  122  the ends of the rail segment are welded to the adjacent rail segments. 
         [0025]    The process described in conjunction with the flow chart of  FIG. 6  is particularly advantageous at locations where several adjacent shoulders need repairs, or where a segment of rail needs to be replaced or reconditioned anyway as normal part of maintenance. In an alternate embodiment, e.g., where only one or two shoulders need repair, an abbreviated procedure may be used. In this procedure, the rail is unclipped from several ties (e.g., six ties) and then pulled away laterally from its supports. The pads and insulators are removed, the ties and shoulders are cleaned, the shims are installed on the shoulders with epoxy, and the rail is pulled back to its original position. The rail can be shifted laterally back and forth either manually or with a hydraulically assisted device. 
         [0026]    Numerous modifications may be made to this invention without departing from its scope as defined in the appended claims.

Summary:
In a railroad system a track is formed of ties positioned at predetermined intervals along the right of way, and supporting a pair of rails. Shoulders are disposed in pairs adjacent to the sides of each rail and are partially imbedded in the ties to limit the lateral movement of the rails and define the track gauge. Between each pair of shoulders there is provided a pad disposed under the respective rail. Insulators are provided between the sides of the pad and a respective shoulder. Over time, friction between the insulators and the shoulders may cause excessive wear. This wear is compensated by one or more shims attached to the shoulders by a strong adhesive.