Tell’s fast train (7)
I believe the answer is:
express
I believe this is a double definition.
'tell's' is the first definition.
(thesaurus)
'fast train' is the second definition.
(I've seen this before)
(Other definitions for express that I've seen before include "Fast train; specific" , "Squeeze out - speak" , "Swift" , "Of train, travelling rapidly with few or no stops" , "Articulate, give voice to" .)