In the scene with the sled dogs, the dogs are connected wrong. The ganglion hitch is used in North America. In Russia, they would use a fan hitch.
The text and map at the start of the film show countries that the Sowjet Union allegedly forcibly occupied during World War II.
This is not true.
As a result of the Molotov-Ribbentrop Pact the Sowjet Union invaded the Baltic states, parts of Finnland, Poland and Romania.
During and after the second World War the Sowjet Union never forcibly occupied Albania or Yugoslavia as shown in the map.
CO-17-774 steam locomotive was built in 1937 as as CO-19-774 and only in 1958 was converted to CO-17-774.
In one shot of the train, modern locomotive (probably TEM-TMH) is visible.