All the London railway stations :
Underground lines : Metropolitan, National Rail Chiltern Railways
AccessAble Access Guide :
Accessibility friendly : Harrow on the Hill is not accessible to wheelchair users due to stairs between the platform and street level.
No stair-free entrance/exit.
Level interchange between fast, semi-fast and ‘all stations’ Metropolitan line trains running in the
General description : See wiki
More comment : National Rail Map and guide
Inclusive Britain Station Guide