Boltar wrote:
They tried the system where trains set off at 2 minute gaps without
the hindereance of signals about 100 years ago.....too many
crashes....You might be a bit late for a meeting or dinner...but
this is safe.

I'm not suggesting ignoring signals, I'm just trying to figure out the
logic
behind the system they use now. Signal has failed so go slow across
the
next 2 working signals. Don't get it. Signals don't fail to green
(supposedly)
so if the signal after the failed one is green why on earth go slow
past it,
why not just go normal line speed? It just seems OTT.


Because of something called an "overlap". In order to provide protection for
the next train ahead the signal is positioned before the start of the track
section it controls access to. The length of the overlap varies according to
the weight and speed of the trains plus an allowance for bad weather.

If driver's resumed normal speed after passing only one signal at clear or
caustion there might be another train or other problem withing the overlap.
Then no one gets home for tea.

If you want to learn about how the underground works, and why it's done the
way it is, try http://www.trainweb.org/tubeprune