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A bit out of date, but this interactive map of step free London is very good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 : District, London Overground (West London line), ThamesLink
AccessAble Access Guide :
Accessibility friendly : Partial. District line (A step 123mm/gap 50mm). Open Mondays to Saturdays 0700 until 2345 and Sundays 0800 until 2345 only. The London Overground station is very accessibility friendly. All trains carry a ramp for wheelchair access - Please seek assistance from station staff.
Level access between street and platform, including London Overground and National Rail services.
General description : See wiki
More comment :National Rail Map & Guide,