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A bit out of date, but this interactive map of step free London is very good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, National Rail Chiltern Railways
AccessAble Access Guide :
Accessibility friendly : South Ruislip is not accessible to wheelchair users due to about 30 stairs between the platform and street level. This applies to the National Rail and the Central lines.
General description : See wiki
More comment : National Rail Map and guide