Linear Induction Motor Research Vehicle Wheel/Rail Adhesion Test

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Linear Induction Motor Research Vehicle Wheel/Rail Adhesion Test

R. P. Chen / G. O. D'Sena

A principal factor in the design of effective propulsion and braking systems for new rail transportation equipment is the available adhesion vs speed characteristics of steel-wheel-on-steel-rail vehicles. Objectives of the LIMRV wheel/rail adhesion test were: (1) to obtain, over a wide speed range, empirical data that complements the considerable body of data available from previous low-to-moderate-speed investigations, and (2) to determine the extent of loss of available wheel/rail adhesion with increasing vehicle speed. The results obtained are qualitatively compatible with published data on moderate-speed tests; at high speeds, however, degradation of the attainable adhesion coefficient was not apparent. This test program indicates that wheel/rail adhesion may not limit the maximum safe speed of wheel/rail vehicles to the degree previously assumed. It is also evident that for the LIMRV, which has a higher speed capability and apparently a larger attainable wheel/rail adhesion coefficient than a conventional vehicle, the running rail surface exerts a more pronounced effect on the maximum attainable adhesion than does vehicle speed. The measured adhesion values were greater than expected at the higher speeds, but the maximum attainable adhesion coefficient was not determined because of force limitations of the present braking system. It is therefore believed that further testing of the LIMRV could significantly add to the existing body of knowledge on wheel/rail adhesion, particularly in the area of attainable adhesion vs speed relationships.