They have their feet on the seats. Their iPods sound like mosquitoes with boots on. What are you going to do?
Look, you are on holiday now and you don't know those kids. No one is expecting you to solve this problem, so stop twitching like that.
Some teachers shed their teaching selves in the time it takes to open a beer. Others still wake at dawn mumbling their "to-do" lists. Yet for most, all it takes to snap back into teacher mode is one pair of feet on the seats.
How do you relax and stop treating the world as your classroom? If you don't, your summer holiday is only a break on the calendar. It is not enough to be lazy. You have to be irresponsible, too.
This is hard, as it is ingrained in teachers to try to shape their world. Besides, being bossy is fun. I'm not sure I want a holiday from it. I would love to make those kids pick up their crisp packets, but I can't call senior management if one of them hits me because, annoyingly, this is a train.
So if I wanted everyone on this train to obey me, a lot would have to change. Feet would come off seats, iPods would vanish and free newspapers would neatly stack themselves. The girl checking for nits in her boyfriend's hair would be asleep. The child banging the door would be reading a book.
Since none of that is going to happen, I will just have to find a way of not caring about it. Switch off the inner teacher and send the need to control on a holiday. "Stop playing God," as they say.
What exactly does God do, though? I thought the whole point about God was that he doesn't shove us about or make us do things. He gives us all free will. If God was on this train, he wouldn't mind the banging door or the feet. He gave us doors and feet to use as we like.
God is the ultimate lazy teacher. I've only just realised this, but it makes perfect sense. He lets us all muck about and fight if we want to. He did about a week's work several thousand years ago, then felt a bit tired and put one of the kids in charge. Then as soon as the kid's naughty friend Eve got them both into trouble, they were expelled.
Jesus was a worker, though. An amazing teacher, he could enthral classes of thousands with rubbish resources like a couple of fish. He really loved his pupils, and he was totally committed to inclusion - even if you were a Roman centurion and no one else would have you. He laid down his life to get good results for his students. Today's teachers are a bit like him. They work miracles every day but still get crucified at the end of it.
But God? God is a hippy supply teacher. His presence is rarely felt and he just kicks back on his cloud listening to his iPod (or iGod?). It only plays songs about how great he is, while the rest of us poor saps down here are actually trying to change things. When we ask him what something means, God says "Look, it's a mystery. Don't ask questions, man. It's just all about love."
Oh, look, those kids have started fighting now. And I don't have to care because I am on holiday - and I am going to try and take a God-like approach to it.
Catherine Paver is a writer and part-time English teacher.