Motor club's loco controller (6,6)
I believe the answer is:
engine driver
'loco controller' is the definition.
(someone controlling a locomotive)
'motor club's' is the wordplay.
'motor' becomes 'engine' (engine is a kind of motor).
'club' becomes 'driver' (type of golf club).
'engine'+'driver'='ENGINE-DRIVER'
(Other definitions for engine driver that I've seen before include "Railway worker" , "Footplate man" , "Railway employee" , "loco?" , "Once the dream career of schoolboys?" .)