A "queue" is, by definition, line-shaped, therefore it makes sense to define it by its length rather than its size .
So "a long queue".
In contrast, a "crowd" is kind of blob-shaped, so you would say "a big/large crowd".
ell.stackexchange.com/users/42184/Andrew
I can't argue with the logic of previous answers, preferring 'Long'.
But, as a native English speaker, I have to say that 'a big queue' would raise no eyebrows.
ell.stackexchange.com/users/14011/Laurence Payne
Either one is fine to my British ears.
Because of the physical shape of queues, any big queue has to be long, so the words have equivalent meaning in this case.
ell.stackexchange.com/users/4468/David Richerby
As this NGram query shows, long is the right answer.
This doesn't tell you why or even how to remember it , but I agree with Andrew's answer that long tends to be used for one-dimensional objects and big and large for higher dimensions.
An area can be long but not big; take the country Chile as an example.
It's long, and big when compared to my backyard but rather small next to its neighbour Argentina.
ell.stackexchange.com/users/18673/Glorfindel
Only "half-native" here but just today I used "big queue" and it certainly did not raise any eyebrows among the "full-natives" around me.
Additionally to the previous answers I'd say that "big" can be understood as a "category" containing "long" and other "shapes" of "big".
Therefore you could always use the superordinate "big" to replace any of the "subordinate" and more specific forms of "big".
ell.stackexchange.com/users/16350/Patric Hartmann
What's the idiomatic adjective for the noun " queue "?    I waited there in a very  long  queue.   or   I waited there in a very  big  queue.   Or maybe something else?
We're waiting in a BIG or LONG queue?
ell.stackexchange.com
<idioms><adjectives><idiom-request>
ell.stackexchange.com/questions/195143
ell.stackexchange.com/users/12430/Judicious Allure
A "queue" is line-shaped, therefore it makes sense to define it by its  length  rather than its  size, so it is "a  long  queue". However, "a big queue" would not be misunderstood by english natives. A one-dimensional line would usually be described as long, while a two- or three-dimensional shape would be described as big. However, a long line could also be described as big, and it would not be considered too unusual to call a line big.
A one-dimensional line would usually be described as long, while a two- or three-dimensional shape would be described as big. However, a long line could also be described as big, and it would not be considered too unusual to call a line big.