Semester, say, in which one may get to train (8)
I believe the answer is:
terminus
This might be a double definition.
'semester' is the first definition.
The answer and definition can be both related to time as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'in which one may get to train' is the second definition.
(train terminus)
'say' acts as a link.
(Other definitions for terminus that I've seen before include "Victoria, perhaps" , "Destination point" , "End, extremity" , "End (of rail line)" , "End station" .)