The most common and most likely answer to this crossword clue is the 8 letter word DETRAINS
I've seen this crossword clue in The Daily Telegraph
D
E
T
R
A
I
N
S
More clues leading to the result DETRAINS
Buddy explains!
The straight part
We know that "Emerges from railway journey" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case emerges from railway journey = detrains.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 DETRAINS mean?
DETRAINS 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.