"all passengers" vs "all the passengers"

My friend and I have argued about this problem but found no solution yet.
We considered whether “By the time the train left, all the passengers had been on board” or “By the time the train left, all passengers had been on board” was correct
I think “all the passengers” is right. In my opinion, the train is defined, so the passengers are defined too
But according to my friend, it should be “all passengers”. He explained: “all passengers” means in general while “all the passengers” needs a phrase to modify more clearly, e.g., “All the passengers in the Titanic ship would never forget the disaster if they ever survived”
Please kindly help me.

Hi,

I think I’d come down in favour of your explanation - it is ineed ‘all the passengers on the train.’

Alan

Oh thank you very much.
So now I can be sure to tell my friend the answer.

Oh my god, help!
My friend says to me that if the passengers are defined, so it must be “all of the passengers”, not “all the passengers”
But I think both are acceptable.
What are your opinions? Please help me

Hi,

The addition of ‘of’ is simply more emphatic.

Alan

Thank you very much indeed

In addition to what I mentioned in your other thread (Is omitting “would” in this sentence right?), I’d like to point out that the negative version of “all of the” is “none of the”. It would be more natural to use ‘none’ and ‘ever’ in this sentence. For example:
None of the survivors would ever forget this disaster.
.

Thanks very much for your advice