Assessing wagon Instability in long trains using parallel co-simulation technique

Wagon running safety and stability issues, such as wagon rollover, wheel climb, body pitch, bogie pitch and wagon lift, are more prominent in long heavy haul trains due to larger in-train forces (longitudinal and lateral) and more force occurrences. This paper used detailed wagon-train interaction models based on an advanced parallel co-simulation method. This method connects a commercial multibody dynamics simulation software package (GENSYS) to an in-house Longitudinal Train Dynamics (LTD) simulation software package. In this way, the developed models are able to simulate detailed wagon models (three-dimensional with wheel-rail contact and track geometries, by GENSYS) and detailed in-train force models (coupler angles, train braking, train traction, etc. by in-house software package). When needed, a parallel computing technique can process the simulations of multiple wagons simultaneously, which increases the computing speed and simplifies the simulation coordination. Nine simulations were conducted on a 25 km long track section with real-world track grades and curves. The simulation results show derailments can occur when empty or half loaded wagons were placed right behind the remote locomotive consists.