The queue at the ATM was endless

[Bassim]

I am wondering if my sentence is grammatically correct.

The queue at the ATM was endless, and Bob was furious that he had to wait so long to withdraw his own money.

 

[bhaisahab]

I would make it two sentences: 'The queue at the ATM was endless. Bob was furious...'

 

[emsr2d2]

I find the use of "endless" a little odd when used for something like a queue, which clearly has an end. However, your meaning is entirely clear.

 

[JMurray]

not a teacher

I agree with emsr2d2 to some extent. The hyperbole of "was endless" feels more like conversation.
"Where have you been?"
"Oh, the queue at the ATM was endless. I thought I'd never get my money".

In the written form you've given us, perhaps "seemed endless" works better.