All the London railway stations :
Elmers End is on the South Eastern rail network, and is accessible to wheelchair users. The tramlink is highly accessible. See pictures and further accessible transport in London detail from links below.
National Rail South Eastern & London Tramlink
Accessibility friendly : National Rail - Yes. Tramlink - Yes.
General description : The London tram network runs from
Wimbledon through Croydon to Beckenham. All access to trams is step-free.
All tram travel is free for wheelchair users, who can easily wheel on and off
the trams. There are two dedicated spaces for wheelchair users to travel in each
tram. Next to the wheelchair space is a specially sited intercom, which allows
you to speak to the driver in an emergency, and an easy reach stop request
button. All doors have an opening button on them at an accessible height.
At Wimbledon Station there are passenger lifts providing connections to other rail services. See wiki
More comment : National Rail Map & Guide - step free access to both platforms, platform 1 is via sidegate. Ticket Office and Car Park are step free.