1. Technical Field
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.
2. Description of the Related Art
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.
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.
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.
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.
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's life, and replacement is costly.
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.
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.
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.
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.
Referring to
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 23b is segmented into two separate pieces 23b1, 23b2 that are separated by both the frog 31 and the unbroken inside main rail 21b.
Referring now to
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 (
Referring now to
As wheel 43 transitions from rail 23b1 to toe 33 of frog 31 (
By the sequence of events shown in
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 21b having a continuous beam mounted to the ties 34, and a side rail 23b mounted to the ties 34 and crossing the main rail 21b, the side rail 23b being divided into a toe segment 23b1 and a heel segment 23b2 that are located on opposite sides of the main rail 21b. The frog 31 has a toe 33 and a heel 35 mounted to the main rail 21b, with the toe 33 being aligned with and secured to the toe segment 23b1 and the heel 35 being aligned with and secured to the heel segment 23b2. Both the toe 33 and heel 35 have non-uniform cross-sections in a direction aligned with a line of the side rail 23b.
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 23a 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 23b makes contact with the main rail 21b 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 21b 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 21b during at least a portion of the crossing of the main rail 21b. Moreover, the wheel 43 may simultaneously contact both the heel 35 and the main rail 21b during at least a portion of the crossing of the main rail 21b. Furthermore, the wheel 43 may simultaneously contact all three of the toe 33, the main rail 21b, and the heel 35 during at least a portion of the crossing of the main rail 21b.
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 21b. The flangeway 47 of the toe 33 extends continuously between the inclined surface 47 and the continuous beam 21b, 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 21b, and a contact surface 53 of the heel 35 is a same vertical height as the continuous beam 21b and the heel segment.
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.