An important task in the initial design stages of rapid-transit type systems or "metros" is the allocation of signals and control points. These are placed so as to achieve a specified minimum time-separation between trains (headway), whilst minimizing the amount of signaling equipment but maintaining the highest level of safety. Conventional signaling and control systems are based on the fixed-block principle, whereby the track (or guide way) is divided into sections of predetermined length. A train is only allowed to proceed into a block when that block and usually the next one is clear of traffic. With the moving-block concept, a train can follow a preceding train at a safe braking distance behind the tail of the train.
In this paper, the transient performances of the two signaling systems are compared. A multi-train simulator which was originally developed at Birmingham University (U.K.) with a fixed-block algorithm, has been adopted and modified to accommodate the moving block algorithm. Both signaling systems were applied to Singapore Mass Transit Railway (MTR) and the results were compared in terms of train movement and transient performances including headway and station delay under safety and speed restrictions. Results have shown that with a pure moving-block system a considerable improvement in transient performance can be achieved.