The switch rail (or tongue) is a very sensitive component in terms of both machining and structure, used at the beginning of the switch part of the turnout. The main function of this part is to change the direction of the train from a straight path to a curved one and vice versa. Given that the profile of the switch rail differs from the profile of the rail used in the middle section of the turnout, the end of the switch rail must be forged to precisely match the shape and dimensions of the opposing rail profile. Consequently, forging is one of the most essential processes that must occur on the tongue profile.
The reason for the differing profile of the switch rail compared to other rail profiles is that a significant portion of the length of the switch rail must slide onto the corresponding slide chairs when changing direction, while other rails used in the turnout are secured to base plates with corresponding fasteners. As a result, a height difference arises due to the differing thicknesses of the base plate and the slide chair, which is resolved through the forging process.
The switch rails are movable and are connected to each other via a connecting rod. The simultaneous displacement of both switch rails allows for a direction change in movement. Two positions are defined for the switch rails: “open position,” which allows the vehicle to move onto the main track, and “closed position,” which allows the vehicle to continue on the branch track.