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' indicates a hidden word.
'NORA' is hidden within 'train or automobile'.
(Other definitions for nora that I've seen before include "Girl's name" , "Woman" , "-- Batty (Last of the Summer Wine)" .)