On 18 Mar, 14:13, Peter Fox wrote:
The typical door release delay at Victoria is about 15 seconds - one
would hope that this can be achieved at SPILL, Farringdon and City. 90
seconds at each of those = timetable chaos.

Silly me, but why have any delay at all? *What am I missing?


GPS is used tell the train's computer where it is and so stopping the
doors being opened when there is no platform along side (e.g in an 8
coach train the computer would only allow the front 4 coachs' doors to
be opened when at a 4 coach station). Victoria is undercover and so
the GPS system can't get a fix from the satelites. I can't remember
whether the GPS is overridden or if they have a fake transmitter at
Victoria, but the delay is in switching the whatever the backup system
is. The delay used to be longer than 15s.