Collision risk analysis based train collision early warning strategy.

A Train Collision Early Warning System (TCEWS) has been developed for collision avoidance. However, there are few studies regarding how to evaluate the collision risk and provide an early warning concerning a preceding train on the railway. In this paper, we have found that the time for collision avoidance is constrained by the timing of events, such as wireless communication latency, driver reaction, safety protection distance and deceleration rate. Considering these timing components, the time to avoid a collision is calculated accurately. To evaluate the potential collision severity when the following train approaches, the collision risk is defined based on the time to avoid a collision. The train collision early warning signal is divided into a four-tier color-coded system based on the collision risk, with red representing the most severe collision risk, followed by orange, yellow and blue. A field test of the train collision early warning strategy on the Hankou-Yichang Railway is analysed. It is demonstrated that the strategy has sufficient capability to indicate a potential collision and warn the following train.