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A bit out of date, but this interactive map of step free London is very good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 :
National Rail : ThamesLink
Accessibility friendly : Step-free access to Ticket office only. No step-free access to platforms. Nearest step-free staffed station is East Croydon. The nearest step-free station staffed part time is Norbury.
General description : See wiki
More comment : National Rail Map & Guide.