My acceleration due to gravity checked by device used when driving train (7)
I believe the answer is:
cortege
'when driving train' is the definition.
'cortege' can be an answer for 'train' (both can mean a procession following behind). I'm not sure about the 'when driving' bit.
'my acceleration due to gravity checked by device' is the wordplay.
'my' becomes 'cor' (both are expressions of surprise).
'acceleration due to gravity' becomes 'G' (as in G-force).
'checked by' indicates putting letters inside.
'device' becomes 'tee' (tee is a kind of device).
'g' inserted into 'tee' is 'tege'.
'cor'+'tege'='CORTEGE'
'used' is the link.
Can you help me to learn more?
(Other definitions for cortege that I've seen before include "Processing figures" , "train" , "Solemn funeral procession" , "Entourage, retinue" .)