Abstract
M.Ing.
A signal is an apparatus that safely provides visual information to the train driver of
availability, route and safety of the way ahead and enables him to decide how to control
his train. These signal units consist of a number of lights that display the required aspect to the train. The need for safer and more effective train control methods become more important as the number, speed, mass and length of trains increase. By extending the number of aspects to include 'flashing-aspects, i.e. switching some of the aspects on and off at a constant rate, more information can be conveyed to the train driver. A systems) needs to be introduced into the interlocking in order to produce these aspects. This dissertation explores the implementation of a dc-to-dc switching converter, in a relay interlocking environment, in order to produce an oscillating voltage for these flashing aspects. The reliability of the system is improved by a modular design of power supplies and equal current sharing is implemented by means of current-mode control. The results presented show the system performing satisfactory in the signalling environment and being able to cope with varying loads.