Pierce through vehicles I will leave to repair (8)
I believe the answer is:
transfix
'pierce through' is the definition.
(I've seen this before)
'vehicles i will leave to repair' is the wordplay.
'vehicles' becomes 'trains'.
'will leave' is a deletion indicator.
'to repair' becomes 'fix' ('fix' can be a synonym of 'repair').
'trains' with 'i' taken away is 'trans'.
'trans'+'fix'='TRANSFIX'
(Other definitions for transfix that I've seen before include "Stun in horror - run through" , "Paralyse with sudden emotion" , "Entrance" , "Render motionless" , "Make still with horror or astonishment" .)