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A bit out of date, but this interactive map of step free London is very good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 : Bakerloo, London Overground (Watford DC Line)
AccessAble :
Accessibility friendly : Bakerloo is not accessible to wheelchair users due to stairs between the platform and street level. It is also inaccessible to changes from Bakerloo line to Overground services.
General description : See wiki
More comment : National Rail Map & Guide, 35 steps to platforms.