The impact of end-to-end communication delay on railway traffic flow using cellular automata model

• An improved CA model for moving block system is proposed.
• The improvement is to consider the end-to-end communication delay in CA model.
• The impact of end-to-end communication delay on railway traffic flow is discussed.
• Relationship between end-to-end communication delay and line capacity is analyzed.

Increasing number of railroads have begun to operate with a moving block system that relies on a data communication system to transmit real-time information such as train position and velocity. The end-to-end communication is a critical component to ensure the efficiency and the safety of train operation. The delay in the end-to-end communication affects every aspect of the specification and operation of the moving block system and therefore deserves special attention. In this paper, an improved cellular automata (CA) model is proposed as a tool to perform analysis of this delay issue through defining neighborhoods in the cellular automata railway traffic model. Based on this model, simulation of traffic flow in a transit system is conducted and the results are presented to demonstrate the dependability of the proposed model. The study shows that, if the end-to-end communication delay satisfies the requirement described in the Euroradio specification, the throughput of railway line (in number of trains per hour) is nearly the same in the simulation scenarios when running the 3 schemes we derived. However the influence on each individual train is not negligible. As one of delay factors, d3 should be kept as small as possible to minimize the headway time.