Lateral Track Forces at High Speed Curving Comparisons of Practical and Theoretical Results of Swedish High Speed Train X2000

Abstract

This paper initially describes the main features of the radial selfsteering bogies, which have been developed for the high speed train X2000. suburban trains and other applications. One of the main goals with these bogies is to reduce lateral track forces at high speed curving.This development has been supported by extensive theoretical investigations parallel to practical tests and verifications. Since around 1973 the main tool for theoretical analysis has been time domain simulations of non-linear vehicle-track models under influence of perfect and irregular track geometry. There are models for verticaVlongitudinal and for lateral dynamics. The models are assembled and utilised in a specialised computer program, SIMFO, and in a more general computer code, GENSYS, the latter having full 3-dimensional capability. A frequently used model for lateral dynamics of a four-axle bogie vehicle with 37 degrees of freedom (DOF) is shown as an example. In order to avoid an unrealistically stiff lateral coupling between wheel axles and ground, this model contains lateral track-ground elasticity and I or lateral and torsional DOF for each wheel. By comparison with measurements it is shown that characteristic quasistatic and dynamic behaviour can be simulated with accuracy.

Motion sickness on tilting trains

“…Trains whose car bodies are actively tilted were first introduced Ͼ70 yr ago and are now in wide use over the world (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). The tilting compensates for the centripetal acceleration during turns by bringing the vertical axes of the cars closer to the gravitoinertial acceleration (GIA), which is the summation of the equivalent acceleration of gravity and the centripetal acceleration.…”

The importance of kinematics accuracy in modelling the dynamics of rail vehicle moving in a curved track with variable velocity

“…No matter how the adaptation of the equations is performed, imaginary forces appear explicitly in (2). Andersson et al (1995), Berghuvnd and Stensson (1998), Kisilowski and Knothe (1991), Popp and Schiehlen (1993), Yang and de Pater (1991) and Zboinski (1998Zboinski ( , 1999Zboinski ( , 2004) may be mentioned here as the examples for traditional building of equations of motion. Gimenez et al (1991), Scott (1989) and Zboinski (2001) might be used to serve the AGEM methods, with the corresponding ULYSSES (Choromanski and Zboinski, 1995) and VAMPIRE (as reported in Kortum et al (1991)) software packages.…”

“…However, some references (e.g., Andersson et al, 1995;Berghuvnd and Stensson, 1998;Popp and Schiehlen, 1993;Scott, 1989) neglect a few, most, and even all such terms. It happens so despite they often are initially present in the equations in some of these references.…”

Modelling dynamics of certain class of discrete multi-body systems based on direct method of the dynamics of relative motion

“…It can be expected that especially the last one of the mentioned equations has got certain disadvantages [39] connected with its numerical efficiency. One can see that determination of imaginary forces according to (46) means carrying out operations on components of vectors and tensors. In case of big systems it is many quite complex, but also recurrent operations.…”

“…They are usually done without complete knowledge what consequences of particular simplifications might occur, however. Publications [1,30,46,47] can be mentioned as the examples where such simplifications could be identified.…”