The most common and most likely answer to this crossword clue is the 7 letter word DETRAIN
I've seen this crossword clue in The Guardian
D
E
T
R
A
I
N
More clues leading to the result DETRAIN
- Leader of riot in hold to get off transportation
- Run into delay? Get off at Crewe maybe
- Evacuate carriage, finding alien in tube
- Stop holding edge of door and get on the platform
- Get off? I daren’t move!
- Stop keeping end of taper alight
- Journalist recalled retinue had to get off at a station
- Alight from French TGV?
- Keep around third of fires alight
- One of the CID to come down and alight on platform
Buddy explains!

The straight part
We know that "Get off" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case get off = detrain.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DETRAIN mean?
DETRAIN verb- To exit from a train; to disembark
- To remove a passenger or passengers from a train; to evacuate passengers from a train.
- (of an athlete) to reduce one's training, particularly during the offseason, in preparation for a cycle of retraining.