Longitudinal forces in railway track and tamping machine shifting sets

Following American and British experience some attempts have recently been made in Poland to determine the axial forces in a rail by using the constra ined transverse displacement technique. The method is based on vertical dis location of a rail section separated from the rail-track up to a certain he ight with the registration of force used for this purpose. An original test ing apparatus has been made to measure the forces and displacements. Taking advantage of experimental investigations it was possible to point out that horizontal displacements of the rail are indispensable. Hence, further inv estigation tasks were concentrated on constrained horizontal dislocations o f the entire track grate. Using a specially prepared apparatus it was possi ble to measure the axial forces within the tamping machine shifting set and the transverse track displacements with various tensile forces in the rail s (in the range of 0-500 kN). It was indicated that the tamper is a machine that can be employed for the determination of axial forces in rails using the constrained transverse dislocation technique. The method provides a cap ability of precise control of the displacement values. It is also possible to utilize measuring force and displacement testers and to create an operat or's station. However, the problem is complex, which is indicated by the pu lse mode of the horizontal force characterized by a much variable rime char acteristic. (C) 1999 Elsevier Science Ltd. All rights reserved.