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A bit out of date, but this interactive map of step free London is very good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 :
Carshalton Beeches is on the ThamesLink, and is not accessible to wheelchair users to access platforms. See pictures and further accessible transport in London detail from links below.
National Rail : ThamesLink
Accessibility friendly : There is no step-free access. Nearest step-free station is Sutton.
General description : See wiki
More comment : National Rail Map & Guide.