This sentence seems fine to me - in the UK at least people get on a train more often than they get in a train. Maybe the sentence seems wrong in American.
This is a broken sentence
I guess that we are trying to say " when do we get in the train?" but the English at the moment is nonsense.
Edited 04.12.18. ...it was nonsense. It is now good.
When do we get on the train
Is good English ... at last.
I've been able to do this unit okay before, but the new track is very unclear. The last two words are difficult to hear.
When do we board the train?