Today whilst waiting at Baker Street, I noticed a purple lamp light up right at the start of the running tunnel. It seemed to come on briefly as the train entered the far end of the platform, and was extinguished before it came to a halt.
The lamp itself looked like a single aspect LU style signal. It seemed to work independently of the red/green signal.
What does it mean?
The lamp itself looked like a single aspect LU style signal. It seemed to work independently of the red/green signal.
What does it mean?