On 2015-03-07 23:38:01 +0000, Paul Corfield said:

I'm obviously guessing here but there are not many refuge sidings on
the ELL core section so you really need to get trains beyond Surrey
Quays to be able to hide them away somewhere.

I was wondering when watching it being built what they would do for
contingency - it seems very little. The elevated section down to
Shoreditch used to carry four tracks and one would have thought a
siding could have been put in there.

E.