Influence of Modified Powertrain Masses on the Ride Comfort of a Light Rail Vehicle

Abstract

Lower powertrain masses and new integration possibilities can be accomplished by using high-speed machines. Since a changed powertrain means a change of the overall system, the aim of this paper is to examine the effects on the system property passenger comfort. This is done using a simulative approach. First, a multi-body model of a Flexity Zurich, a low-floor vehicle that has been operating in Zurich since 2020, is created using the software Simpack. Subsequently, a run on line 9 is simulated and evaluated according to common methods for determining the passenger comfort of rail vehicles. In detail, these are the Sperling method and the Continuous Comfort method according to DIN EN 12299. In order to investigate how powertrains with high-speed machines affect passenger comfort, the model is modified. Machines and gearboxes are replaced by new components that lead to a significant reduction in the mass of the powertrain. It is shown that a concept that leads to a 13% reduction in the primary suspended mass does not have any significant impact on passenger comfort in the simulated vehicle on the specified route. Neither does a concept that leads to a 35% reduction in primary suspended mass and a 38% increase in unsprung mass. In order to gain an insight into the influence of the unsprung and primary suspended mass on passenger comfort, a series of simulations are carried out to investigate this relationship on a broadband basis on the above vehicle. The results show that there is no evidence of a correlation between the unsprung and primary suspended masses and passenger comfort in the lateral direction. However, there is a slight trend towards better comfort values in the vertical direction with lower unsprung and primary suspended masses.