The most common and most likely answer to this crossword clue is the 8 plus 7 letter word HOGWARTS EXPRESS
I've seen this crossword clue in The Guardian
H
O
G
W
A
R
T
S
E
X
P
R
E
S
S
More clues leading to the result HOGWARTS EXPRESS
Buddy explains!
The straight part
We know that "online literary creation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case online literary creation = hogwarts express.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.