Study of the derailment safety index Y/Q of the low-floor tram bogies with different types of guidance of independently rotating wheels

Abstract

Modern tram designs use different conceptions of how to implement the low-floor functionality. The key construction part is the bogie running gear which has to accommodate the lower part of the tram body. To adjust the low-floor level, many low-floor tram bogies have different types of guidance of independently rotating wheels with no central axle between the two wheels. Lack of self-steering mechanism in the form of central axle coupling or an external guiding device creates several inherent problems, such as insufficient guiding and excessive wear. Another important context is the safety against derailment when the vehicle negotiates a curved track. In this study the dynamic behaviour of non-powered bogies with different types of guidance of independently rotating wheels are presented using computer simulation models. The simulation results of the Y/Q index are compared for the two track configurations (curved and tangent sections) and four different kinds of bogie running gear.