| Abstract: | Couplers of motor units connect the wagons mechanically, electrically and pneumatically. Nowadays they are also designed to meet crash requirements. Since the traction and braking forces are distributed along the motor unit, coupler forces occuring during operation are considered to be low. In most cases, this is actually true. However, towing away a defect motor unit by another motor unit can lead to high forces due to longitudinal vibrations, which may ultimately lead to a failure of the coupler or superstructure. Investigations on the behaviour of motor units operating in an European city have been carried out for about 3 years Kühnel, A., Hecht, M., Udriste-Breazu, I., Geike, T. and Böhme, C., Kräfte beim Bergen liegengebliebener U-Bahnen—ein unterschätztes Risiko. ZEVrail-Glasers Annalen, Tagungsband SFT Graz, 2004, pp. 128–136; Udriste-Breazu, I., Böhme, C., Kühnel, A. and Hecht, M., Behaviour of Motor Unit Couplers in Towing Case. 4th International Symposium on Passive Safety of Rail Vehicles, Okt. 2003, Berlin, Germany, homepage www.ifv-bahntechnik.de.]. The research has always been focussed on the certain parameters and conditions of the motor units under study. Little effort has been made to theoretically study the problem on a general basis. The aim of this paper is to close this gap. |
