There are two trains going from Moscow to Peking every week:
Train №004 Moscow¬ – Peking (through Ulan Bator)
departures from Yaroslavskiy station on Tuesdays at 21:35 and includes Chinese formation luxury class coaches with 2-berth compartments (with a shower in each compartment), second-class 4-berth compartments, also first-class 4-berth compartments.
The train goes through Mongolia (you will need a transit visa to use this train), stops at Erlyan, Dzinin, Datun, Chzhanzyakou stations.
the train goes back towards Moscow on Wednsdays at 07:45.
Train №020 Moscow – Peking (through Manchuria)
departures from Yaroslavskiy station on Saturdays at 23:55 and moves to China through Manchuria. the train with RR/FPA formation includes luxury coaches (first-class, 2-berth compartments) and coupe (second-class, 4-berth compartments) and stops at Manchuria, Haylar, Boketu, Anansi, Dazin, Harbin, Chanchun, Sypin, Shenyan, Dzinchou, Shanheigua, Tanshan, Tyandzin.
the train starts back towards Moscow on Saturdays at 23:00.