I think that we reached the Mongolian boarder around 10 am. After handing over my passport and getting out so that the cabin could be inspected I went back to sleep. I woke up when my passport returned but fell right back to sleep. At the Russian boarder I had been expectiong a search and questioning. We had to get out of the cabin for a minute, but other than that they took my passport and brought it back with a stamp about an hour later. I couldn't believe it, I had reached my travel Everest!
We waited at the boarder for ages. I had exchanged some of my backup money for rubles and was able to stop by a shop for some fresh food. The shop was really weird, everything was behind a counter and you had to tell the woman what you wanted. It took ages.
Around 4 pm the train began to move again. I read for a bit, but mostly watched movies on my ipod before falling asleep.