I was on a 165 formed of 3 x 2 carriage sets the other day, sat at the
front of the back 2 car unit. The driver passed the signal and by the
time my coach got to the signal, (as you'd expect) it had a red aspect
showing, but why wasn't the train 'tripped?' Do all the tripcocks
become inactive apart from the ones in the 1st unit when they're
coupled together, or do the train stops raise after a delay (say
30Secs) or so to allow the train to pass over?