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A bit out of date, but this interactive map of step free London is very good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 : Central
AccessAble Access Guide :
Accessibility friendly : No entrance/exit. You can change between the eastbound platform towards Liverpool Street (B step 173mm/ gap 140mm), westbound platform towards West Ruislip (B step 207mm/gap 123mm) and National Rail services.
No stair-free exit. Escalator access between street and platform, including National Rail services, entrance only.
General description : See wiki