Experimental analysis of profile degradation of high-speed turnouts: A case study in China

Abstract

Railway turnout is an essential component in the track system, which allows two tracks to intersect at the same level and consequently divert trains. Due to wheel-rail forces and structural weakness of turnouts, switch blades and crossing noses are easy to be damaged, which can lead to significant changes in the running behaviour of trains, especially for high-speed railways. However, the measurement of the profiles of high-speed turnouts is rarely presented in existing studies. This paper presents an experimental study of the profiles of high-speed turnouts that are both replaced and in operation. The turnouts studied are the Type 18 high-speed turnouts with a swing-nose crossing used in the Zhenjiang Station in the Shanghai-Nanjing high-speed line in China. The defects and worn profiles of the replaced switch blades and swing-nose rails during the first seven years of operation (2010–2017) are studied. Besides, the profiles of two turnouts both in the facing and trailing directions measured over four years (2015–2018) have been presented. The common defects, service life and pattern of profile degradation of high-speed turnouts are discussed, which can be helpful for railway companies to make inspection standards or to optimise designs for high-speed turnouts. The main findings are that curved switch blades are the most frequently damaged rails in high-speed turnouts. Its service life varies from 2 to 5 years, which is much longer than that of swing-nose rails and strongly determined by the driving direction of trains. The wear in the facing direction grows far from the tip, with a maximum of 59 mm2/year, while that in the trailing direction grows close to the tip with a maximum of 27 mm2/year.