Quantifying Rolling Noise Reduction by Improvements to Wheel-Rail Interface Management

Vancouver SkyTrain noise has historically been highly variable. Corrugation in both curve and tangent track has been a maintenance challenge since the system opened, with changing rail surface condition between maintenance cycles resulting in up to 26 dBA variation in rolling noise emissions. This paper describes the outcomes from pilot studies and investigations to quantify the potential rolling noise reduction achievable by modifications to wheel-rail interface conditions, including harder rail steel; acoustic rail grinding and top of rail friction modifiers. The study demonstrates that reducing the cyclic variation in rolling noise is feasible. The objective is to optimize maintenance practices and wheel/rail interface conditions to keep train passby noise emissions within 5 dB of the best case (minimum) noise at all times.