When a 100 or so bright young students go on a journey together, one should expect something more than just generic travel documentation. Photos, diaries and such are of course important and valuable, but this kind of an adventure offers great possibilities for something even greater – in the true sprit of an expedition.
I propose miniature research projects for all participants. See the special environement of the train from the angle of your expertise – or perhaps try doing research in someone else's field? In “tongue-in-cheek” -style or maybe something more profound – the choice is yours.
Study the microeconomics on a Trans-Siberian train, the various cultural collisions, local knowledge of Finland, time zone travelling – effect on the appetite?, hygienics on a Siberian train, architecture in rural Siberia through the window of a moving train, physical phenomenas of the moving train, samovar – the magical contraption, “close quarters” - experiences sharing the personal space …
I would support a psychological research of people on the train.
Lasse Korpela commented
Sorry for the Finnish, but maybe in lines of: http://tutkimus.parvi.fi/index.php/Mik%C3%A4_on_mikroartikkeli