In a well-known railway system, a locomotive or train travels along two (2) substantially-parallel drive rails. The train may be used to transport goods (e.g., a freight train), or may be used to transport people (e.g., a passenger train), between or among destinations. The train includes one or more motors, which may be powered by diesel fuel and/or electricity, and includes one or more train cars for driving the train and/or for transporting the goods or passengers.
Each train car includes at least two (2) wheels on the left side as well as at least two (2) wheels on the right side thereof. Typically, the train car includes at least four (4) to six (6) wheels on each side. Regardless of the number of wheels on the train car, each wheel includes a flange on its left side as well as a flange on its right side. For each wheel, both the left-side and the right-side flanges extend radially and have a diameter greater than a diameter of a surface of the wheel which contacts and rolls on the drive rail. By this arrangement, contact is maintained between each wheel and the drive rail on which the wheel rolls, because the flanges keep the wheels from slipping off the drive rails. Thus, derailment of the train car is prevented.
Guardrails are disposed along certain portions of the railway system in order to provide additional protection from the train car becoming derailed. For example, when the drive rails define a turn having a radius smaller than a predetermined value, one or more guardrails are placed on the outside of the turn. In particular, the guardrails are disposed about parallel to the drive rail on the outside of the turn, and are spaced apart from the desired and expected path of the wheels. Guardrails are also used along other portions of the railway system, such as where one set of drive rails crosses over another set of drive rails. Thus, in the event that the wheels might otherwise begin to slip off the drive rail, the sides of the wheels will contact the guardrails, and derailment of the train car will be prevented.
U.S. Pat. No. 7,467,748 (the '748 patent) gives an example of a guiderail support assembly that does not use bolts to secure the guiderails to the braces that hold and position the guiderails. Instead, the '748 patent uses a hook device to mount each of the guiderails to the braces. Because the '748 patent does not use bolts to secure the guiderails, disadvantages common to a bolted system are avoided. For example, in a bolted system, the precise locations of the bolt holes in the braces must be measured. Then, corresponding bolt holes must be machined or otherwise formed in the guardrails, when the replacement guardrails are being custom manufactured for bolted-installation on the braces. Thus, guardrail replacement in the '748 patent can be accomplished more quickly and less expensively, and with less tooling, because custom bolt-hole patterns are not required to be formed in the replacement guardrails.
The '748 patent suffers from its own disadvantages, however. For example, the guardrails must have a specialized cross-section to fit the specific geometry of the braces disclosed in the '748 patent. Throughout the world, the number of guardrails that are manufactured is far fewer than the number of drive rails produced. Thus, manufacture of the guardrails, such as through forging the specialized cross-section, is relatively expensive per unit as compared to the manufacture of the drive rails, which are a standard component of the railway system and are used in much greater quantity.