Signalling is a safety- and service-critical metro asset. Across CoMET and Nova metros, signalling is the second-highest cause of delay incidents, and cause approximately half of all delay incidents for very reliable metros. This study analysed information from 26 metros about their signalling equipment, looking in detail at six sub-assets: point machines, interlockings, track circuits, axle counters, train stops, and signal heads. The study compares these sub-assets, including their age, reliability, and inspection/maintenance regimes, and collects initiatives that metros are pursuing to improve signalling reliability.
Metros with older and more traditional signalling systems tend to have more trackside signalling equipment, which may lead to more potential for failure and greater need for maintenance interventions to maintain reliability. To improve signalling reliability metros are rationalising their asset bases, as well as pursuing both solutions that can be retrofitted into their existing systems and new systems such as CBTC.