In message , Chris
writes
While at another station I heard an announcement to the effect that Green
Park had been closed due to "defective safety equipment"

With signals being safety equipment, is this another way of saying
"Signal Failure"?

Nah, usually means the fire alarm has gone defective. Had it been
signals they'd have been queuing back to Acton in short order.
--
Steve Fitzgerald has now left the building.
You will find him in London's Docklands, E16, UK
(please use the reply to address for email)