wintersummer, I've never tried to use a hair dryer on a train, but i did charge my cell phone in the "shaver's only" outlet once, so i'm guessing you'll be okay. But the cabins - even those with showers - are kind of small. Is there any chance you can go a few days without washing it?

And I have applied mascara in a moving train, but if you're nervous about it then why not wait until you pull into a stop?

PS. if you decide not to wait, suggest you have some Q-tips handy as they're the best thing for getting rid of mascara mistakes.