Cringe, having to discern what's in front of train (10)
I believe the answer is:
cowcatcher
'in front of train' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'cringe having to discern' is the wordplay.
'cringe' becomes 'cower' (synonyms).
'having' means one lot of letters goes inside another.
'to discern' becomes 'catch' (I can't justify this - if you can you should give a lot more credence to this answer).
'cower' placed around 'catch' is 'COWCATCHER'.
'what's' is the link.
Can you help me to learn more?
(Other definitions for cowcatcher that I've seen before include "device for clearing tracks" , "Lasso" , "metal frame" , "Maybe rancher" , "Protective frame on the front of some trains" .)