Bogies towards higher speed on existing tracks

Abstract

Running faster on existing tracks is a common operator's wish that should be set in relation to the necessary infrastructure maintenance costs for track quality enhancement. Designing a track-friendly running gear that exerts moderate forces on the track is a key to relax this relation. A design providing good ride quality even on non-perfect track is preferred to avoid excessive track maintenance costs when speeds are higher. This paper describes how simulations and tests have been performed to optimise certain parts of a high-speed bogie. The result is a bogie with relatively soft wheelset guidance allowing passive radial self-steering in common curve radii, which in combination with appropriate yaw damping ensures stability at higher speeds. It also includes active secondary suspension to further ease the maintenance requirements on the track and/or to improve ride quality. This bogie has been tested and approved according to EN 14363 for a service speed of 250 km/h in combination with enhanced curving speed. Both simulations and recently performed on-track tests further showed that the ride comfort with active secondary suspension at 250 km/h can be at least as good as with passive suspensions at 200 km/h.

Green Train: concept and technology overview

“…The result is a smoother ride in the car body. According to simulations, at least the same ride comfort can be achieved at 250 km/h with active suspension as at 200 km/h with passive suspension [10]. These results are confirmed by on-track tests at speeds A further advantage of active suspensions is that the suspension movements are reduced, thus allowing a wider car body, further improving passenger comfort.…”

“…Radial self-steering (RSS) bogies, capable of running stably at speeds well above 250 km/h, have been developed and tested [10], both in functional and certification tests and in commercial service for 700,000 km. These bogies have been tested under track conditions exhibiting limit values for 160-200 km/h.…”

“…Newly developed technical systems have been tested in this way, e.g. design for noise reduction [8,9], new bogies and suspension [10], improved aerodynamics [11] as well as new traction motors and a high-speed pantograph (see Section 8). Special designs for winter operation have also been tested.…”

Damage Tolerance Assessment of a Brake Unit Bracket for High-Speed Railway Welded Bogie Frames

“…To keep higher safety and reliability of bogie frames for a light rail vehicle, three fatigue assessment procedures in terms of equivalent stress ranges have been carefully examined using highly loaded welded joints, such as the endurance limit approach with the maximum loading amplitude, cumulative damage approach with the loading spectrum of fatigue test program, and cumulative damage approach with the vertical force range spectrum from MBS simulation. It has been confirmed that the MBS-based loading spectrum provides more realistic loads, which act on the bogie frame, for fatigue assessment, depending on the actual railway conditions [3,[14][15][16]. However, it is well-known that the fatigue assessment based on the endurance limit approach provides relatively conservative results for the allowable stress and accumulation damage; nevertheless, such an approach serves as a quick and standard procedure for the safe life analysis of railway safety-critical components [17][18][19].…”

Application of yaw dampers with frequency-selective damping to improve the locomotive adaptability to low/high conicity stability

“…Therefore, a reasonable selection for yaw damper parameters is particularly noteworthy, which can improve lateral ride comfort and reduce the wheel-rail lateral force. [11][12][13][14] Yan et al 15,16 deeply investigated the impact of the yaw damper's damping and series stiffness on the bogie stability and bifurcation type, and integrated the central popular theorem with the paradigm method to acquire the expressions for critical speed and bifurcation types, which were related to the damping and series stiffness of yaw dampers. Xia et al 17 developed a bogie mechanical model with four degrees of freedom, and researched the impression of yaw damper's suspension parameters and installation position on lateral stability, ride comfort and steering ability.…”