Case study: poor visibility of OFF indicator
14 March 2024
New LED indicator resolves visibility issues.
On darker days, the OFF indicator for signal MP389 – on platform 14 at Manchester Piccadilly station – is visible. But it’s hard to read it when it’s sunny. Moving elsewhere on the platform doesn’t help, said the reporter to CIRAS. They believed the display was too dim and there was no shade from the sun. When a signal’s OFF indicator is lit, it means a train can pass the signal. If an OFF indicator is blank, it means the signal is red (danger). If station staff can’t read the OFF indicator, they might dispatch a train against a red signal, which could lead to a signal passed at danger (SPAD).
Network Rail accepted that the display wasn’t as bright as indicators on other signals nearby, which had already been upgraded with LED displays. Its signalling and telecommunications (S&T) staff at Manchester Piccadilly attended the site, cleaned the signal contacts, checked that the voltages were correct, and renewed the lamp.
The S&T staff ordered an LED OFF indicator for this signal and fitted it in February this year.