Dynamic effects of vehicles on tracks in the case of raising train speeds

In order to enhance the efficiency of railway transportation, Chinese Railw ays has decided to raise the speed of trains on the existing railway main l ines. A theoretical model and the corresponding simulation software, VICT, based on the vehicle-track coupling dynamics are employed to analyse dynami c effects of trains on track structures caused by raising train speeds. Chi nese passenger cars and freight cars running on the lines where speed has b een raised were chosen for investigation. It is shown that raising train sp eeds on the existing railway lines obviously intensifies the dynamic effect s of vehicles on tracks, especially in the turnouts, in the welded rail joi nts, and in the sections of bridge-subgrade connections. The occurrence of wheel flats becomes more general after raising train speeds. An unfavourabl e peak of dynamic effects of wheel flats on tracks is observed in the speed range from 140 to 160 km/h, which is just the region of running speeds for passenger trains after the increase in the speed. Some basic countermeasur es, including stricter maintenance standards for the speed-raised railways, are proposed to solve these problems, on the basis of dynamic analysis.