Electrical switch point heatings consist of heating rods that are attached to the rail with clamps. Usually these clamps have a width of w ≤ 35 mm and they are set in a distance of d = 30 cm to each other. The clamping force and the resulting thermal contact resistance in the area of the clamp was previously investigated. Due to the large proportion of the heating rod that is not covered by a clamp and the uncertainty of the mechanical properties of the heating rod, a clear statement about the distribution of the mechanical stress at the contact area in longitudinal direction cannot be made. That means the thermal contact resistance can vary in a large range. In order to determine the impact of varying thermal contact resistances at the clamp area and at the area between the clamps, a Finite Elements Method (FEM) model of a rail and an attached heating rod was set up. Heating calculations with various thermal contact resistances show that the temperature distribution in the rail is mainly affected by the thermal contact in the clamp area. The heat transfer into the rail does not benefit from an increased clamping force or a special treatment of the rail surface like milling or usage of a thermal-conducting paste. Even a reduction of the clamping force over time due to mechanical or thermal load on the clamps does not decrease the temperatures significantly in the rail. However, the temperature distribution within the heating rod is strongly dependent on the thermal contact resistance in the area between the clamps. A large contact resistance between the clamps causes very high temperatures at the heating rod that accelerate ageing processes and can eventually lead to the malfunction of this part.

switch point heating; heating rods; heat transfer; thermal contact; FEM-Calculation, thermal contact resistance