Simulation of railway brake plants: An application to SAADKMS freight wagons

Abstract

The UIC railway braking system is a complex pneumatic plant whose performance and reliability are safety relevant. The plant is controlled by the transmission of pneumatic signals; different train compositions involve large parametric variations of plant response. The problem is critical for long freight trains where the delayed plant response involves heavy longitudinal forces between vehicles. Even for simple compositions of 10-15 vehicles, the number of components involved in the plant response is quite high. The distributor valve, a complex pneumo-mechanic device, is devoted to control the brake response on every vehicle and it is perhaps the most difficult component to be simulated.Authors have developed simulation models of the pneumatic plant of the UIC railway brake including libraries of pneumatic submodels that can be parametrically calibrated in order to reproduce different train compositions.In this work, a case study concerning the simulation of a convoy composed by the SAADKMS freight wagon is presented. Simulation results are compared with experimental data kindly supplied by Trenitalia SPA. Model formulation and calibration procedures are shown in order to explain the followed workflow.identify the response of the plant from a reduced set of experimental results available from the Trenitalia SPA.The proposed procedure may be interesting in order to produce a robust tuning of simulation models against errors due to the uncertainty of parameters.

Railway Air Brake Model and Parallel Computing Scheme

“…The authors' experience indicates that a mesh size of at least 1 m per section is recommended to simulate the details of air brake system behavior. This mesh size is also recommended by Pugi et al [23]. In terms of numerically stiff components in air brake systems, these are components that have small volumes, such as the upper chamber in the distributor and a low pressure brake cylinder.…”

Design of a hydraulic servo-actuation fed by a regenerative braking system

“…Inertial effects which are usually with lumped mono-dimensional elements (I) are neglected considering the low dynamical behaviour of the plant. The adopted approach is quite common in literature [20] and also adopted by authors for the simulation of plants and fluid networks with uncompressible [21] compressible fluids [22] or multiphase one, such as steam [23]. Dynamical behaviour of the controlled 4/3 valves: valves are modelled considering the equivalent response of a second order system (eq.…”

Train Braking

“…Due to the importance of the air brake distributors response to the pneumatic signals transmitted through the brake pipe, there were performed numerous theoretical and experimental studies regarding these aspects, based on more or less simplifying hypothesis, all tending to highlight mainly the brake cylinders filling characteristics as accurate as possible (Belforte et al, 2008;Cantone et al, 2009;Piechowiak, 2010;Pugi et al, 2004Pugi et al, , 2008.…”