2017 – March – Moore – Signalling system safety is NOT an absolute

Trevor Moore Hon FIRSE FIEA Aust Australian Rail Track Corporation We often design a signalling system and continue its operation even though there are significant changes in train operating conditions. Do we assume that is still as safe as the day it was commissioned into service? Some cases are self-evident that safety has changed. If we increase the train speed over a level crossing we know that the approach warnings have to be reviewed and updated. Do we check and update if they have changed the road traffic classification to B double trucks? When and how should we review the signalling system for safety of operations? What should be the catalyst to undertaking a review? Should this be part of the standard practice for signal engineers managing infrastructure and for signal designers on new works? The paper addresses some of the situations that can arise leading to a change in the safety of the signalling system.