Petty Officer in transport route is also a bouncer (10)
I believe the answer is:
trampoline
'a bouncer' is the definition.
(I've seen this before)
'petty officer in transport route' is the wordplay.
'petty officer' becomes 'po' (naval abbreviation).
'in' is an insertion indicator.
'transport route' becomes 'tramline' (I can't explain this - if you can you should believe this answer much more).
'po' placed into 'tramline' is 'TRAMPOLINE'.
'is also' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for trampoline that I've seen before include "Trap oilmen (anag.)" , "Spring up" , "bouncer" , "where pike may count in competition" , "On which bouncers go" .)