Third body layer-experimental results and a model describing its influence on the traction coefficient

When adding substances to the wheel-rail contact, they mix with wear particles and form a Third Body Layer (3BL). This layer influences the initial gradient of the traction characteristic. During twin-disc tests presented in this paper, a granular layer consisting of iron and iron oxides with a thickness of up to 50 mu m was found. In addition, a creepforce model is presented that uses non-linear properties of the 3BL to describe its influence on the traction characteristic. The results of the model were compared to the results of the experiment A qualitative and quantitative agreement was achieved. This will improve, e.g., the quality of vehicle dynamics simulations, optimizations of control devices for traction and braking, and predictions of wear and damage on wheel and rail. (C) 2013 Elsevier B.V. All rights reserved.