Forgot the name of this Cold War themed movie?

I was recently thinking of the title to a movie I saw as a kid but I've totally lost all recollection of it. All I can remember is that it was a Cold War themed movie and I feel like it came out in the late 80s. I remember the beginning and it went like this: A dawn landscape in the flat Russian countryside. There's a train in the going in the background. It turns out that this train is carrying a nuclear warhead and it's passenger cars are full of sleeping Soviet soldiers (presumably to guard it). Then these spec op guys with night vision goggles get on with red laser sights on their guns and the camera pans out (assuming that they massacre the sleeping soldiers). Then the camera goes back to the dark, flat landscape and suddenly, the nuke goes off. That's all I can remember. If you know the title of this film, please let me know!