you are in fact brave! I heard sometimes one might get robbed at night. I've been gone for 15 years though, perhaps it's gotten better safety-wise.

I remember traveling in the platzkart when I was 7. my brother wanted the top bunk and fell off it in the night.
I did it again from Moscow to Odessa when I was 10, and that was way more fun since a slew of us were traveling together. 24 hours later every time I set down anywhere, I felt the shaking and the monotonous train wheel beat.