Russian Railways has scheduled another, third, double-decker train for service on the Moscow-St. Petersburg line. It is currently scheduled only for service from January 18 to April 24, according to Travel.ru.
Departure from Moscow daily, except Saturday, at 21:24, arrival in St. Petersburg at 5:19. Return departures daily, except Sunday, at 0:40, arrival in Moscow at 10:05.
Ten compartment cars are currently on sale. Fares start at 1,278 rubles for upper berths and 1,476 rubles for lower berths.
It's worth noting that one of the two existing double-decker trains (departing at 9:50 or 9:55 p.m. from both cities) will be renumbered as of December 10th, becoming the 23/24, receiving the branded status and name "Smena," and correspondingly more expensive tickets (starting at approximately 2,000 rubles for a compartment). The other train, departing at 10:50 p.m., will retain its current status and offer slightly lower fares. As a reminder, ticket sales will open 90 days prior to departure starting December 10th.
Source: travel.ru