Train #79/80 is an express which operates on St. Petersburg - Kaliningrad route. It also makes a short stop in Vilnius. The train is managed by Russian Railways. It covers 1327 km and goes through the territory of 3 countries: Russia, Belarus and Lithuania.
There are 2nd class and 3rd class carriages in this train. 2nd class cabin has two upper and two lower sleeping berths. 3rd class has all berths together in an open coach. There is also a restaurant car
NOTE: Since the train crosses Belarus, you will need Belarus transit visa for the trip.