In article ,
Tom Anderson wrote:
Okay, so my solution is slightly facetious, but only slightly - i don't
see how opening the right number of doors needs to be terribly expensive.

The testing required to prove a safty-critical piece of kit would,
I expect, be larger than you think.

By making something more complicated, you tend to reduce its
reliablity, so you need to factor in the cost of increased downtime
and increased maintaince over the lifetime of the kit.

Don't get me wrong: I think they could have done a number of things
that would have worked, been safe, kept the line open, and probably
cost less than shutting the line[1]. But I'm prepared to admit
that I don't know all that much about runnin a railway, and could
be wrong.


[1] eg run with 6 doors that open at the Stratford end of all platforms,
and lock out the car at the other end of the train. On the flag day,
run with 7 doors that open on the platforms, and ban 6-car trains.

--
RIP Morph (1977-2005)