The most famous train routes in Russia are probably between Moscow and Saint Petersburg, the two biggest cities in Russia. To travel this routes you may take a regular train or an express train. By express trains it only takes you 4 hours. The regular trains are made for long distances and mostly sleeper trains. You can see three different carriage types of these carriages: first class (SV), second class (Kupe), third class (Platskart). In these trains you will have beds in which you can sleep but some additionally have seating carriages. The difference in the different classes is the amount of beds in one enclosed room:
First class: two beds
Second class: two lower and two bunk beds
The third class doesn’t have an enclosed room and has 4 beds.
Concerning regular trains the most popular one is Red Arrow which operated at the times of the Soviet Union to take the Communist Party elite between Moscow and Saint Petersburg (name at that time was Leningrad). There is a theme song for this train which will be played at time of departure from the train station. The train goes every day at the best times that you will have time to sleep during the ride and that you will arrive early at your destination.
As for the express trains you can take the ‘Sapsan’ which goes three times every day. Especially business travelers like to take this train because it is very fast and comfortable.
Nevertheless, the most extravagant train is the Grand Express. The different classes are VIP, Premium, first and second class. The highest comfort you will experience in VIP, Premium or first class. Though the second class resembles the Red Arrow train and goes every day.
These are not the only trains running between Saint Petersburg and Moscow but also a lot of branded trains. These do not differ in their price so you should make your decision by times of departure and arrival. It depends on you if you want to be there very early for a meeting or if you want to sleep a little longer.