Train-track Interaction Model Research Articles

Two-material rail development: field test results regarding rolling contact fatigue and squeal noise behaviour

Results from the European 5th Framework project “InfraStar” are presented. The InfraStar project is developing a two-material rail to increase the productivity and reliability of rail infrastructure. The two-material rail aims to be rolling contact fatigue (RCF) resistant and to reduce squeal noise. The InfraStar consortium has built a high level of wheel–rail expertise and understanding regarding RCF initiation and development, level and position of wheel–rail contact forces, and new interface materials and has gained experience in both laboratory and field test operating conditions. Within the project a validated theoretical train–track interaction model and a fatigue design model for two-material rails have been developed. This paper focuses on the field test results of the two-material rail, and how the predictions and expectations from the selection process match with the results observed in track. Results are very promising. The two-material rail prototypes, now over 1 year in track, show no RCF damage where the non-treated rail shows clear RCF damage. The development of the application process and other objectives of the InfraStar project are discussed.

Prevention of RCF damage in curved track through development of the INFRA‐STAR two‐material rail

ABSTRACTResults from the European 5th frame research project ‘INFRA‐STAR’ are presented. The goal of the project is to prevent rolling contact fatigue (RCF) and to reduce squeal noise in curves by applying an additional surface layer material on the top of the railhead, resulting in a two‐material rail. In INFRA‐STAR, a dynamic train–track interaction model is used to provide the contact forces. Wheel‐rail profiles, wheel‐rail friction, vehicle data, track data and operating conditions are included to calculate the wheel‐rail contact forces and spin moments, contact positions and load distributions in the contact patch. The contact pressure, friction coefficient, coating thickness, material properties of the coating and the rail material are used in finite element calculations and shakedown theory to calculate shakedown limits, which are then used to predict the RCF performance of the system. The paper details the work on theoretical modelling, twin disc testing, metallurgical research and field testing completed to date (August 2002, the project just passed midterm). The development of the surface layer application methods that are used, and the further objectives of the INFRA‐STAR project, are discussed.

Simulation of Interaction Between a Train in General Motion and a Track

Summary An existing state-space based numerical method to simulate vertical dynamic interaction between a rolling train and a railway track is improved and extended. The model is extended to enable general three-dimensional motion of a train traversing a track. For the vehicle description a multibody dynamics method is used which allows for flexible components, for example, wheelsets. The track model is accordingly made three-dimensional in the sense that it allows for deflections and forces in all three directions at the wheel-rail contact. A track and a train in general motion imply two-dimensional modelling of the contact surface. Therefore, a linearised contact model including contact zone detection is proposed. The equations of motion of the system are formulated in a first-order form. The generalised dynamic train-track interaction model is verified against existing programs and good agreement of the results is obtained.