I prefer travelling by train in Russia, I like to look outside of the window and see places, so I will share couple of videos about Russian trains, so you can know what to expect. I will let fellow Americans tell you this story.
2 Storeys Russian Train
This is what we call coupe. You have a room for 4 people and you can close the door to your compartment. There are toilets and shower available. Clean sheets are provided. Food is also provided if requested.
Econom Class Train This what we call it platzcart. The area is shared with other passengers. You get to meet new people, so it is fun too.