Girl in train or automobile (4)
I believe the answer is:
nora
'girl' is the definition.
(girl's name)
'in train or automobile' is the wordplay.
'in' says the answer is hidden in the clue.
'NORA' is hidden in the letters of 'train or automobile'.
(Other definitions for nora that I've seen before include "Girl's name" , "Woman" , "-- Batty (Last of the Summer Wine)" .)