Abstract
Track geometry standards have been enforced for more than ten years in the French Railway Network. Limit values were derived from experience, and up to now they remain a good guarantee of train running safety. The very high speed intensive commercial circulation (V > 300kph) on long distance on high-speed lines as well as the advent of new types of vehicle could require determining limit values adapted to these new conditions. The study consists of using vehicle simulation software for evaluating the consistency between the current track geometry standards and the safety criteria for vehicle acceptance. The possibility of using such software for determining track geometry standards has also been investigated. The influence of track defects on the behaviour of a TGV, running at different speeds and in various conditions, has been analysed for different criteria of defects such as amplitude, wavelength and shape. The study shows that current track geometry standards appropriately cover the studied cases in spite of results close to the limit for very-short-length defects. Moreover, defect wavelength and shape both seem to be important factors in vehicle dynamics. This study has also helped to define a new method to update track geometry standards (V > 22 0kph) and to explore needs for a new very high-speed standard (V > 300kph).