The hospital worker possibly rode on the railway (7)
I believe the answer is:
orderly
'the hospital worker' is the definition.
(I've seen this before)
'possibly rode on the railway' is the wordplay.
'possibly' is an anagram indicator.
'on' is a charade indicator (letters next to each other).
'the railway' becomes 'rly'.
'rode' is an anagram of 'orde'.
'orde'+'rly'='ORDERLY'
(Other definitions for orderly that I've seen before include "Officer's assistant" , "in a mess? No" , "Neatly arranged; hospital attendant" , "Systematically, not haphazard" , "Methodical; hospital worker" .)