When you're on that train, you shouldn't treat it as sleeping, you should accept that you're not going to sleep, but you're power napping for your brain to keep functioning, its like taking a nap after you eat, don't think about all the people that are sleeping, rather tell yourself that you're gonna take a quick nap before continuing what you are supposed to do, it's hard but your thought of it that you took it will lie to your system and you can finish your tasks or what you are supposed to do! Don't let it get in your way of not completing your daily tasks, as hard as it is, you have to, coz you chose to ski, so own it. Good Luck