This conference paper was submitted for presentation at the NAFEMS World Congress 2025, held in Salzburg, Austria from May 19–22, 2025.

Abstract

Railway vehicles are fascinating machines, running for immense timespans and distances delivering continuous performance, with lifespans of up to 40 years and typically running around 1.000 km daily. Keeping performance over such lifespans makes them engineering masterpieces. The most stressed and safety critical part of railway vehicles are the bogies, constituting the physical connection between carbody and rail. All forces between the vehicle and the ground are transmitted via the bogie. This must be accounted for during the engineering phase of the bogie to guarantee the desired lifespan, putting stringent requirements on the engineering processes regarding reliability and stability. This leads to a strong emphasis of virtual product development methods in railway bogie design. Almost all the design and optimization is done using simulation models. The first bogie that is built is the first product from serial production, there is no intermediate prototype which is optimized physically. The validation of the system requirements, including validation of homologation related requirements, is performed using one of the bogies from serial production. This validation - simply put, physical measurements showing requirement conformity '“ constitutes the top level in the V-model shaped design process. The validation of the topmost layer of the assessment quantities of vehicle dynamics in the V-model is always performed to check system requirement conformity. Nevertheless, assessment quantities with a high impact on the overall design process and engineering iterations, such as spring travel, play a minor role in the validation procedure. Using operational measurements, an MBS (multi-body system) model of a Vectron locomotive was validated with respect to the primary spring travel occurring during operation. Primary spring travel is derived from top-level system requirements during the design process. It has great influence on the derivation of subsequent requirements, like requirements for primary springs. The validation was performed on several levels, starting from simple, quasistatic spring travel resulting from constant traction forces, ranging to validation of dynamic amplitudes up to a check of the frequency content of the spring travel signal. The models'™ predictions of the primary spring travel were found to be very accurate. They could be further improved by adapting some detailed component parameters, which are of secondary importance on the first glance. The work highlights the importance of comprehensive model validation of MBS Models to improve the predictive aspects in design processes of future bogies.