Analytical Approach to Railway Signal Block Design

Abstract

Originally intended for rapid transit systems, it is also applicable to any rail system where high-speed, short-headway characteristics are required to maintain a smooth and efficient flow of passengers or goods. Analytical techniques are used to select system speed commands using a cost-benefit analysis; to determine the speed-location operating profile; to locate signal block boundaries; and to determine signal logic. Four computer programs are used to calculate station dwell times, to simulate train performance, to calculate safe braking distance, and to determine headway. These programs determine the highest feasible speeds, consistent with civil design restrictions, at which trains can travel while at design headways. The algorithm for block layout then ensures that the minimum number of blocks will be used to provide the design headways subject to all system limitations. Program inputs include car characteristics and track profile, user demand statistics, and the design headway.