All the London railway stations :
Feltham is on the South West rail network, and is very accessible to wheelchair users including lifts available to cross between platforms. See pictures and further accessible transport in London detail from links below.
National Rail : National Rail South West
AccessAble Access Guide :
Accessibility friendly : Yes.
General description : There is level access to both platforms. There is level interchange between platforms using lifts. The lifts are in operation when the station is staffed until 00.30 everyday. See wiki
More comment : National Rail Map & Guide