All the London railway stations :
Amersham station is largely only accessible heading southbound towards Liverpool Street on the Metropolitan line. There are newer Metropolitan trains which are much more accessible due to step / gap sizes considerably reduced. The national Rail service is totally inaccessible to wheelchair travel, and there are no train boarding ramps available. See pictures and further accessible transport detail from links below.
Underground lines : Metropolitan, National Rail Chiltern Railways
AccessAble Access Guide :
Accessibility friendly : Partially? WC (female only, southbound platform). You can only enter and exit the southbound platform for trains towards Liverpool Street (A step 250mm / gap 40mm). There is Level access between street and southbound platform only, towards Liverpool Street.
New, more accessible trains are currently being introduced on the Metropolitan line. The step and gap onto the train will vary. If you require level access onto the train, you will need to board a new train
National Rail - There is step free access between the street and Platform 3 for Southbound Metropolitan Line services. Customers need to be aware that there is a step between train and platform of up to 200mm for London Underground services. There is no step-free access between the street and Platforms 1 and 2 for Chiltern services. Boarding ramps are not available at this station.
General description : See wiki
More comment : National Rail Map and guide ;