At the first Soviet mission of Yuri's Revenge rather that going back to Red Alert 2 the Soviet Remnants go back much further...
...back to October 8, 1917. All the Soviet forces that participate in the 1st Part of Time Shift make the jump back in time. Including the stuff the Soviets capture.
The plan is to leave San Francisco with as much stuff as possible and join Lenin in his October Revolution and Russian Civil War
Infantry: Conscripts, Flak Troopers, Engineer, Attack Dogs, Tesla Troops (Two Battalions of each Unit Type) and Boris
Buildings: 1 Hospital, 1 Allied Repair Bay, 1 Neutral Repair Bay and 4 Neutral Power Plants (Guess strip them of parts and study the buildings to rebuild them in Russia)
Land Vehicles: Rhino Tanks and Flack Tracks (One Battalion of both)
Air Vehicles: MiG-29UBs (12 of them)
Navy Vehicles: Dreadnoughts, Submarines, Sea Scorpions, Giant Squids and Amphibous Transports (55 of each)
Just to make things simple, the Time Machine blows up after the Time Jump but not before Zofia and the Commander leave it. The Time-travelers only have blueprints for making Nuclear Reactors, Radars, War Factories, Iron Curtain, Nuclear Missiles and Sentry Guns plus all Soviet Infantry and Vehicles. No More Time-Travels.
Not sure how Lenin and the Reds would react to their new and powerful Allies and the news of the future
The Giant Squids alone give the Reds a massive naval advantage