Again you are forgetting that I know that this yard is a busy depot and maintenace yard with many workers and with constant in and out traffic. So it is more than just an assumption that he did not try to attract attention.
I agree with the rest.
I acknowledged this above; however, even in a busy depot and maintenance yard, there are periods in the day when the activity around one particular bus may be nonexistent. If a child does not try for more than a few minutes to garner attention (and so many kids have such short attention spans that they will assume that calling for help/banging on windows/doing X is fruitless because it didn’t work within a few minutes), then there is less chance of that child being discovered.
Unless this story is updated, we don’t know how much, or for how long (if at all) this kid tried to attract attention before he gave up to find ways to entertain himself. It probably did not occur to this kid, until the hours stretched by, that any adult would be away for more than a few minutes.