This is really cool. Instructions are in Russian but not too hard to figure out, Day of the trip is determined by clicking the bars at the top. Click on a wagon to start the trip: http://www.rzd.ru/images/flash/
[WS:] Been there, done that. Back in my day, however, the cars had shower cabins for every two compartments - a feature that regrettably seems absent from the current arrangement, given a six day journey. But the samovar at the end of the car is still there.
120 km/h does not seem like the lighting speed, by the European standards, and it was about the same 30 years ago AFAIR. However, Amtrak does not fare any better outside the NE corridor. BTW, I also took Amtrak from NYC to SF and LA and back, as well as China Railway from Beijing to Canton and back, so I can say that I have traveled around the world by train (as much as possible). This is such a civilized way to travel, even if speed is not that great.
Wojtek