They lead the way in our present transport system (8)
I believe the answer is:
reindeer
'present transport system' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'they lead the way in our' is the wordplay.
I cannot really understand how this works, but
'lead' could be 'rein' and 'rein' is present in the answer.
'way' could be 'e' (Compass direction - East) and 'e' is present in the answer.
The remaining letters 'der' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for reindeer that I've seen before include "D [DECORATION]" , "Eg, Prancer and Dancer" , "Arctic ruminant" , "Santa's Prancer, say" , "Red-nosed Rudolph is one" .)