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A bit out of date, but this interactive map of step free London is very good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 :
Elephant & Castle is on the Northern and bakerloo underground
lines, and is largely not accessible to wheelchair travellers or those with difficulty walking.
From southside entrance:
There is lift access between street and southbound Northern line platform ONLY.
There is lift plus 35 steps between street and norththbound Northern line
There is a lift plus 43 steps between street and Bakerloo lines
From northside entrance:
There is a lift plus 63 steps between street and southbound Northern line platform ONLY.
There is lift access plus 53 steps between street and norththbound Northern line
There is a lift plus 20 steps between street and Bakerloo lines
See pictures and further accessible transport in London detail from links below.
Underground lines : Northern, Bakerloo, ThamesLink
Accessibility friendly : No. You can only enter and exit the Northern line southbound platform for trains towards Morden (A step 183mm/ gap 3mm).
Lift access between street and southbound Northern line platform ONLY without climbing further stairs, towards Morden.
General description : See wiki