My first contact with Belarusian rail was in Berlin even before boarding it, and it was an olfactory one: the coach to Minsk exhibited a slight but noticeable smell of oil. However, inside the coach it was quite cosy and comfortable. Curtains at each window, carpet with an old-fashioned pattern in the corridor and in the compartment. The bed/seat covered in red velvet and even a small table cloth on the table.

However, and this be a big warning to anybody attempting to do this this trip, the main drawback was the missing restaurant coach on this 18 hour trip (for us, others stayed on the train for much longer, like Kiev). The conductress of our coach only had hot water and could sell us some ramen noodles. I know, had they had internet on that trip, the prototypical Computer Science PhD student would not have left the train: the outside world is passing by without interaction, a long night and ramen noodles all the time a perfect habitat. If you wonder, Rollton (Роллтон) is the essential piece of vocabulary here. I, for my part, stuck to the mixture of healthy (apples, mandarins) and unhealthy food (chocolate) that I had obtained in the last minutes before departure, probably following some kind of instinct.
The only two exciting events happened in the middle of the night: entering Belarus which meant being woken up by several sternly looking people in differently coloured uniforms wearing differently shaped hats that examined our passports and asked if we were bringing alcohol, cigarettes or household appliances. We did not, at least not according to Belarusian custom rules: everything that has less than 7% of alcohol is not considered an alcoholic beverage.
The other event is exciting for rail enthusiasts and a slight annoyance to other passengers. As in all parts of the former Soviet Union, the rails have a broader gauge than in the western part of Europe. The solution to that challenge is to lift each coach, to exchange the wheels underneath and to put the coach down on the rails again. This is less exciting than it sounds, even considering that you stay in the coach. The train enters some kind of garage, the coaches are uncoupled, moved to some kind of hoisting platform, slowly lifted and put down again. Had it not been for some banging and clanging noises and for the shunting movements, this process would have almost been unnoticeable.

The layout of a long-distance train coach is different, too. They don't have comfortable reclineable seats, but instead two benches facing each other with space for three persons each. However, above each bench there is a bed that can be folded down so that four people can sleep in that open compartment. Across the aisle, there are two seats on a table, facing each other and with some intricate mechanism one can turn this into two bunk beds.