Clive wrote:
In message ,
Brimstone writes
That's my understanding also, the surface building would need to be
located elsewhere in the vicinity.
There's no reason why the escalators can't be from a different part of
the platforms to the current booking hall, is there?

The principle is OK but would depend on the distance between the platforms
and the street. There is also the question of creating overloaded areas of
the platform and hence the train.