Search london history from Roman times to modern day
A bit out of date, but this interactive map of step free London is very good
All the London railway stations :
Underground lines : London Overground (East London line)
Accessibility friendly : No.
There is a long escalator (37 steps) from the ticket office to the station landing. From the landing to the platforms is a further 39 steps.
General description : See wiki
More comment : National Rail Map & Guide - lots of steps.