An Approach for Moving Block Signalling System and Safe Distance Calculation

This study represents a moving block signaling system model. In this system, different from the conventional railway systems, there are access points near the railway and moving trains communicates via them. In this way, not only railway traffic flow is increased but also waiting time for the passengers is decreased, especially in metro lines. In this work, representing a multi-carriage train, multi-degree of freedom mass-spring-damper models are used. Then, a tractive force and braking force are applied to the system as an input and location is obtained from this output. In addition, a limit movement authority is defined for control algorithm. So, trains move according to this authority. Finally, for the safe stop of trains, brake distance value is calculated. This equation is solved depending on the speed of the rear train. So, if the rear train accelerates, the distance will increase according to the square of the speed of the rear train. Besides, depending on the speed of the rear train and travel time, a safety margin distance is obtained. The proposed technic is simulated by using Matlab-Simulink™ and the results including train models, speed profiles, locations, accelerations etc. are shown in Figures.

I. Introduction

In the railway transport, many train control systems are used and operated. The aim of this systems is to prevent accidents caused by trains which travel on the same route. Besides, these systems allow the trains to move safely from a station to another. The conventional signalling systems use track circuits and wayside signals for safe movement. These signals, which are similar to traffic light signals, are called Fixed Block Signaling. In this signaling, trains are divided into many blocks according to the train is in the block or not, the signals could be red, yellow or green. If the track circuit is occupied, the signal is red. If two track circuits are unoccupied, the signal is green. If a track circuit is unoccupied, the signal is yellow. In this system, it is not known where exactly the train is. That means the location of the train is not known certainly [1].