I watched the Soviet unit roster and saw an excellent series of armored trains. Very impressive.
There is an NKPS-42. But I did not see there significant armored trains at the beginning of the war.
It would be nice to see them in the same style.
If you allow me, I will write about them here.
At the beginning of the war, armored trains mainly consisted of two types.
A heavy armored platform with a 1 - 107mm gun is the PT-33 (probably the barrel of the tower should be turned in the direction of movement

)
And a light platform with a 2 - 76 mm gun. This is the PL-35, 37. (you can choose the PL-37 between them slight differences)
These were the most mass series trains. (34 and 14 pieces)
Later, OB-3 was added to them, also a mass series (65 pieces)
In the picture she has a strange trunk (it should be raised higher in my opinion).
Here is another one to have an idea of what the tower looks like.
I saw the version of OB-3, it looks like an armored locomotive itself.
If you make an armored car it will be wonderful.
The remaining various versions could be built in just one or more instances.
But there is also an interesting version of the anti-aircraft armored train with 2 - 76mm АА guns. (in first screen)
I think it would be worth adding at least one armored train with the PT-33 and PL-37 to the barbarossa scenario.
If interested, I can later write the second part, about armored trains that were built and used since 43 years.