COMPUTER-BASED OPTIMIZATION TECHNIQUES FOR MASS-TRANSIT RAILWAY SIGNALING DESIGN

The paper represents an attempt to harness the vast processing power available in modern computers to the task of assisting signal design engineers with the layout and performance assessment of various signalling systems, particularly as applied to metro systems, The primary aspects considered are the minimum headway and line capacity dictated by the dynamics of the train following, particularly across stations; the paper does not report in detail on the further considerations of route setting and interlocking and train regulation under disturbances. After reviewing the basic relationships governing the behaviour of a signalling system, the properties of the track circuit-based, multi-aspect, equi-block system are discussed in detail. A mathematical optimisation technique, which chooses ideal intermediate speeds accounting for equipment response delays and jerk limiting, is presented. Developed software, which then automatically makes trial block layouts on a given station-station run, is described with examples of its output presented. The same software applied to the case of a transmission-based system yielding a moving-block capability shows a useful increase in headway, although it should be borne in mind that the underlying assumptions here may not be as pessimistic as with the equi-block scheme reflecting the smaller experience with transmission-based systems in the UK. Together with the earlier examples, these results demonstrate the great value of computer-aided design techniques in allowing the signal engineer to concentrate on the higher levels of systems performance by making possible quick trial layouts with the minimum of effort.