Author(s)

G.E. Clark

Abstract

In recent years the high passenger demand levels on metres has stretched the existing 'conventional fixed block' signalling systems to their limits and has led the signalling engineer to radically re-think his total system. The developments in transmission systems, particularly radio, coupled with the expanding use of more complex vital processing techniques has enabled new systems to be considered to replace the existing method of safely authorising a train to proceed. The processor intensive nature of these systems require the development of an assurance culture which addresses the whole system life-cycle and gives the level of confidence in the software integrity appropriate to the criticality of the signalling system. History In the mid 1980's, passenger demand was higher than ever experienced by London Underground

Keywords