Still where one might find a train -- a railway! (10)
I believe the answer is:
stationary
'still' is the definition.
(both can mean immobile)
'where one might find a train a railway' is the wordplay.
'where one might find a train' becomes 'station' (train station).
'railway' becomes 'ry' (abbreviation for railway).
'station'+'a'+'ry'='STATIONARY'
(Other definitions for stationary that I've seen before include "Static" , "Not moving" , "Motionless" , "Fixed" , "Unmoving" .)