Refer to Euston, finally, after running on time (7)
I believe the answer is:
mention
'refer to' is the definition.
(synonyms)
'euston finally after running on time' is the wordplay.
'finally' says to take the final letters.
'after' is a charade indicator (letters next to each other).
'running' is an anagram indicator (the letters run around to different places).
The last letter of 'euston' is 'n'.
'on'+'time'='ontime'
'ontime' with letters rearranged gives 'mentio'.
'n' put after 'mentio' is 'MENTION'.
(Other definitions for mention that I've seen before include "state" , "Passing reference" , "Briefly refer to (something)" , "Acknowledge" , "Cite; quote" .)