Abstract:
A railroad turnout lift frog has a combination tread and flange bearing design that uses two separate castings to form the lift frog and securely bolt it to the main rail. The lift frog allows for a continuous, unbroken mainline track and also has built-in guarding for a safer move.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The present invention relates in general to railway track sections and, in particular, to an improved system, method, and apparatus for a railroad turnout lift frog.  
         [0003]     2. Description of the Related Art  
         [0004]     A railway frog is employed where one track crosses another. For example, in a turnout, a switch will selectively switch a train from a main track to a turnout track. As the turnout track progresses in a curve from the switch, one of the rails must cross a rail of the main track. The junction assembly at such crossing is called a frog. If two tracks cross each other, four frogs are required, one at each intersection of one rail with another.  
         [0005]     There are a number of different types of frogs. One type, referred to as a spring frog, has a fixed wing rail and a movable wing rail. The wing rails converge toward each other in a central area of the frog, and then diverge from each other. If a casting, a point member is located between the diverging portions of the wing rails. The point member has point rails on an end opposite the point that are joined to standard rails of the turn out and main track. A spring biases the movable rail against one side of the point member. The flange of a railcar wheel progressing from the main track onto the turnout enters between the movable rail and the point member, spreading them apart from each other. The tread of the wheel passes from the fixed wing rail onto the point. Similarly, when traversing from the turnout back onto the main track, the tread of the railcar wheel moves from the point onto the fixed wing rail.  
         [0006]     In both cases, the tread crosses a gap between the point member and the fixed wing rail, this gap being provided for receiving wheel flanges of railcars that are passing through the frog on the main track. The gap increases the contact pressure of the wheel against the point and the fixed wing rail because the tread will not be fully supported on steel as it passes over the gap. This creates repetitive excessive loads on part of the fixed wing rail and point member that cause them to wear more than other portions of the frog.  
         [0007]     The point member is generally formed of austenitic manganese steel because of its ability to work harden under impact loads and its ability to be repaired by welding. The fixed wing rail of the spring frog can be made of conventional carbon steel as normally used in conventional rails, or the wing portion can be integral to the cast point of austenitic manganese steel. Once the wing portion wears to the point, it is not economical to repair, and the entire casting may be replaced. Replacing an entire casting is a time-consuming and expensive task. A rail made of austenitic manganese steel would be too expensive for the lengthy fixed wing rail.  
         [0008]     In a bolted rigid frog, neither of the wing rails is movable. A flangeway is located on each side of the point member. Consequently, a gap must be traversed each time the tread of a railcar wheel passes between the point member and one of the wing rails. The wing rails of bolted rigid frogs are also formed with rails of conventional rail steel. Consequently, they also tend to wear in the areas that are contacted by the railcar wheel adjacent the point. A railbound frog is rigid with a manganese wing integral to the point. The impact areas can be repaired to a certain point. However, every subsequent repair shortens the casting&#39;s life, and replacement is costly.  
         [0009]     Typically, railroad turnout frogs are the highest maintenance item in a turnout. The flangeway or gap in the frog is necessary to allow the wheels of a train to cross a rail. When the wheels cross the gap they generate impacts that adversely affect the frog, wheels, and the track structure. Although each of the foregoing designs is workable, an improved design that further reduces the railroad maintenance would be desirable.  
       SUMMARY OF THE INVENTION  
       [0010]     One embodiment of a system, method, and apparatus for a railroad turnout lift frog allows for a continuous, unbroken mainline track. A combination of a solid, self-guarded, tread and flange bearing design uses two separate castings are used to form the lift frog and securely bolt it to the main rail. The castings may be manufactured from manganese steel. The present invention also has built-in guarding for a safer move. In one embodiment, the present invention is well suited for low speed turnouts that are necessary for equipment or bad order car set out tracks, or an industrial siding with limited use.  
         [0011]     The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the present invention, taken in conjunction with the appended claims and the accompanying drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     So that the manner in which the features and advantages of the invention, as well as others which will become apparent are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiment thereof which is illustrated in the appended drawings, which drawings form a part of this specification. It is to be noted, however, that the drawings illustrate only an embodiment of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.  
         [0013]      FIG. 1  is a plan view of one embodiment of a lift frog constructed in accordance with the present invention and shown installed on main and side tracks;  
         [0014]      FIG. 2  is a sectional end view of the frog of  FIG. 1  taken along the line  2 - 2  of  FIG. 1 ;  
         [0015]      FIG. 3  is a sectional end view of the frog of  FIG. 1  taken along the line  3 - 3  of  FIG. 1 ;  
         [0016]      FIG. 4  is a sectional end view of the frog of  FIG. 1  taken along the line  4 - 4  of  FIG. 1 ;  
         [0017]      FIG. 5  is a sectional end view of the frog of  FIG. 1  taken along the line  5 - 5  of  FIG. 1 ;  
         [0018]      FIG. 6  is a sectional end view of the frog of  FIG. 1  taken along the line  6 - 6  of  FIG. 1 ;  
         [0019]      FIG. 7  is a sectional end view of the frog of  FIG. 1  taken along the line  7 - 7  of  FIG. 1 ;  
         [0020]      FIG. 8  is a sectional end view of the frog of  FIG. 1  taken along the line  8 - 8  of  FIG. 1 ;  
         [0021]      FIG. 9  is a side view of the frog of  FIG. 1  taken from an inside perspective relative to the main rail; and  
         [0022]      FIG. 10  is a side view of the frog of  FIG. 1  taken from an outside perspective relative to the main rail.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     Referring to  FIG. 1 , a main track  21  and a side track  23  are shown crossing each other. For ease of reference, the two rails of main track  21  are labeled outside main rail  21   a  and inside main rail  21   b . Similarly, the two rails of side track  23  are described as outside side rail  23   a , and inside side rail  23   b . For simplicity, the illustrated embodiment of  FIG. 1  depicts the inside side rail  23   b  crossing the inside main rail  21   b  from left to right. However, those skilled in the art will recognize that the present invention is readily adaptable for crossings by other rails in both directions as is commonly known in the art of railroad frogs.  
         [0024]     A frog  31  is located at the illustrated crossing to accommodate the transition of a train on the side track  23  past the main track  21 . The main track  21  extends continuously through the frog  31 . However, the inside side rail  23   b  is segmented into two separate pieces  23   b   1 ,  23   b   2  that are separated by both the frog  31  and the unbroken inside main rail  21   b.    
         [0025]     Referring now to  FIGS. 1, 9 , and  10 , frog  31  comprises only two components: a front end portion or toe  33  and a rear end portion or heel  35 . Unlike some prior art designs (e.g., U.S. Pat. No. 328,815), the present invention does not require a multi-tie bed plate or a double wedge-shaped bar to support its toe  33 . Frog  31  only utilizes the conventional tie plates  32  ( FIGS. 9 and 10 ) that are used by rails  21 ,  23  and are no larger than the ties  34  themselves as shown.  
         [0026]     The present invention includes raised guards  24  that are integral to toe  33  and to heel  35 . This design is similar to a self-guarded frog. This feature is desirable in that the back of the wheel is used to positively guide the flange over the opened flangeway. A guard  26  comprising a guard bar brace and guard bar  28  ( FIG. 2 ) is also positioned adjacent to the outside rail  23   a  to aid the wheel flange through the heel  35 .  
         [0027]     Referring now to  FIGS. 2-8 , a sequential series of sectional end views of a wheel progressing through frog  31  is shown. In  FIG. 2 , both wheels  41 ,  43  on a railcar axle  45  are shown. However, for simplicity, the other figures depict only the wheel  43  that progresses through the frog  31 . The tread  42  of wheel  41  rides on rail  23 a and its flange  44  is guarded by raised guard  24  as shown. Wheel  41  substantially maintains this configuration throughout the transition of wheel  43  through frog  31 .  
         [0028]     As wheel  43  transitions from rail  23   b   1  to toe  33  of frog  31  ( FIG. 1 ), the tread  46  of wheel  43  contacts and is elevated on an incline  47  on toe  33  such that its flange  48  is positioned in a flangeway  49  (right side of  FIG. 2 ). Portions of both incline  47  and guard  24  are elevated above (i.e., vertical height) the top of rail  21   b . The flangeway  49  extends continuously between incline  47  and rail  21   b  and has approximately the same vertical depth throughout its longitudinal length. Guard  24  has a greater length than incline  47 , such that incline  47  terminates before guard  24  ( FIG. 6 ).  FIG. 3  depicts wheel  43  transitioning to the left and being further elevated, as indicated by the arrows, in preparation to lift wheel  43  over rail  21   b . In  FIG. 4 , wheel  43  has been elevated sufficiently such that flange  48  is able to clear rail  21   b  as wheel  43  continues to move left via frog  31 . At this point, wheel  43  may make contact with both toe  33  and rail  21   b , as shown.  
         [0029]     By the sequence of events shown in  FIG. 5 , wheel  43  begins to transition to heel  35  of frog  31 . For a brief moment during this transition, wheel  43  may make contact with all three elements: toe  33 , rail  21   b , and heel  35 . After wheel  43  (i.e., flange  48 ) is fully supported by heel  35  ( FIGS. 6 and 7 ) on surface  53 , flange  48  of wheel  43  is received by a flangeway  51  ( FIG. 8 ) formed in heel  35 . Flangeway  51  declines to gradually lower the tread  46  of wheel  43  onto rail  23   b   2  ( FIG. 1 ), until the wheels  41 ,  43  completely transition to track  23 . The only portion of heel  35  elevated above the top of rail  21   b  is its guard  24 . Surface  53  is the same vertical height as rails  21   b  and  23   b   2  to provide a smoother transition for the tread  46  of wheel  43 .  
         [0030]     In one application, the frog  31  is designed to be used in a system for crossing a train on a side track  23  over a main track  21 . One embodiment of the system comprises a plurality of railroad ties  34 , a main rail  21   b  having a continuous beam mounted to the ties  34 , and a side rail  23   b  mounted to the ties  34  and crossing the main rail  21   b , the side rail  23   b  being divided into a toe segment  23   b   1  and a heel segment  23   b   2  that are located on opposite sides of the main rail  21   b . The frog  31  has a toe  33  and a heel  35  mounted to the main rail  21   b , with the toe  33  being aligned with and secured to the toe segment  23   b   1  and the heel  35  being aligned with and secured to the heel segment  23   b   2 . Both the toe  33  and heel  35  have non-uniform cross-sections in a direction aligned with a line of the side rail  23   b.    
         [0031]     A tie plate  32  is mounted to each tie  34  adjacent the frog  31 , and the toe  33  and heel  35  maintain contact with the tie plates  32  mounted to each of the ties  34  over which the toe and heel pass, respectively. A frog guard  26  may be mounted adjacent rail  23   a  for retaining a train in a proper lateral position with respect to the frog  31 . The frog guard may comprise a guard bar brace  26  and a guard bar  28  mounted to the guard bar brace  26 . The wheel  43  on rail  23   b  makes contact with the main rail  21   b  as the wheel  43  crosses from the toe  33  to the heel  35 . However, only a flange  48  of the wheel  43  makes contact with the main rail  21   b  while crossing from the toe  33  to the heel  35 . In addition, the wheel  43  simultaneously contacts both the toe  33  and the main rail  21   b  during at least a portion of the crossing of the main rail  21   b . Moreover, the wheel  43  may simultaneously contact both the heel  35  and the main rail  21   b  during at least a portion of the crossing of the main rail  21   b . Furthermore, the wheel  43  may simultaneously contact all three of the toe  33 , the main rail  21   b , and the heel  35  during at least a portion of the crossing of the main rail  21   b.    
         [0032]     In other embodiments, the toe  33  has an inclined surface  47  and a guard  24 , and the guard  24  and portions of the inclined surface  47  are elevated above a top of the continuous rail  21   b . The flangeway  47  of the toe  33  extends continuously between the inclined surface  47  and the continuous beam  21   b , and the flangeway  47  has approximately a same vertical depth throughout a length thereof. The guard  24  has a greater length than the inclined surface  47 , such that the inclined surface  47  terminates in length before the guard  24  terminates. The heel flangeway  51  declines to gradually lower the wheel  43  onto a surface  53  of the heel  35  and the heel segment. Alternatively, only a guard  24  of the heel  35  is elevated above a top of the continuous beam  21   b , and a contact surface  53  of the heel  35  is a same vertical height as the continuous beam  21   b  and the heel segment.  
         [0033]     While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.