Adding a brake shoe temperature model into freight train longitudinal braking dynamics simulations

Published research about brake shoe temperature assessments and the influences of temperature dependent brake Coefficient of friction (CoF) on train braking performance do not consider detailed train dynamics. This paper addresses this research gap by combining a brake shoe temperature model with a detailed Longitudinal Train Dynamics (LTD) model. A simplified one-dimensional (1D) Finite Element brake shoe temperature model was developed. Studies were conducted to assess brake shoe temperatures during cyclic air brakes and single-occurrence air brakes. Results show brake shoe temperatures at different positions of the train can be very different due to brake characteristics variations. During case studies, temperature dependent brake CoF increases train braking distances by 10.2 and 6.6% on down grade and flat tracks respectively. Emergency brake cases have the highest increases of brake distances by 11.3% on down grade tracks

Freight train air brake models

This paper is an outcome of an international collaborative research initiative. Researchers from 24 institutions across 12 countries were invited to discuss the state-of-the-art in railway train air brake modelling with an emphasis on freight rains. Discussed models are classified as empirical, fluid dynamics and fluid-empirical dynamics models. Empirical models are widely used, and advanced versions have been used for train dynamics simulations. Fluid dynamics models are better models to study brake system behaviour but are more complex and slower in computation. Fluid-empirical dynamics models combine fluid dynamics brake pipe models and empirical brake valve models. They are a balance of model fidelity and computational speeds. Depending on research objectives, detailed models of brake rigging, friction blocks and wheel-rail adhesion are also available. To spark new ideas and more research in this field, the challenges and research gaps in air brake modelling are discussed.</p