PROSE investigates the running safety under longitudinal compressive forces for London Underground
Germany-based manufacturer Kirow Ardelt GmbH is to deliver eight-axle railway cranes and switch tilters to London Underground (LU). These on-track machines (OTM) and additional wagons form the London Underground’s Modular Points and Crossing (MPaC) system. The MPaC system will be operated on both LU infrastructure as well as Network Rail (NR) infrastructure. PROSE investigated the running safety under longitudinal compressive forces (LCF) of predefined consists of the MPaC system on LU as well as NR network in different specific coupling configurations i.e. central buffer coupler (drophead buckeye) and screw coupler with side buffers. This was done through accurate multi-body simulations in which the forces in the couplings and buffers, the wheel/rail forces, the lateral overlapping of side buffers and the swing angle of the buckeye coupler were analysed. The most sensitive combinations were identified, and practical solutions were proposed to increase the running safety.
In a first step PROSE clarified the boundary conditions, assessment quantities and limit values as these vehicle configurations are not fully covered by standards. On this basis, multi-body simulations using the software Simpack were performed to analyse the running safety of the different consists. During the stepwise analysis, PROSE put forward proposals regarding practical solutions for sensitive cases, e.g. increasing the ballast of the so-called support wagons in order to increase the safety against derailment of specific consists. A close coordination with Kirow and London Underground was fundamental during the different project phases.
PROSE identified sensitive combinations of rolling stock and coupling configurations and derived possible solutions to increase the running safety. In addition, the underlying effect of the longitudinal compressive forces on the lateral wheel-rail forces via the coupling was described.
This project was driven by PROSE’s vast understanding of the railway system (overview) in combination with specific knowledge e.g. specialties of on-track machines, freight wagon bogies and coupling systems, in combination with profound simulation and analysis skills and a strong theoretical background in vehicle dynamics and physics. The problems were identified efficiently, and practical solutions were proposed.
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