Why does the green line stop so often inbetween underground stations?

Question

Why does the green line stop so often inbetween underground stations?

Answer 1

Presumably you're talking about some subway/metro/underground railway somewhere in the world - but you don't say where... London, Boston, NY, Paris, Manila, the list goes on and on.

One simple guess would be congestion - there's a train still stopped at the station ahead.

Answer 2

Perhaps colour blindness.   Is the "red" line in close proximity?

Answer 3

On the London Underground at peak times the trains are so frequent (up to 1 every 2 minutes) that they often have to stop between stations to wait for the train ahead to clear the next station.

By 'green line' I assume you mean a line covered by a green signal, meaning 'clear to proceed'. The approach to the station would be covered by a red signal ('danger, stop') until the station was clear, then the signal would change to green.

Answer 4

It is a go forward signal.