Just before Stanley Mott meets Dieter Kolff for the first time, near the end of part one, he is standing on a street as a tank goes by behind him. But if you watch the "tank" the tracks aren't moving, and it bounces like a 4 wheel vehicle instead. Obviously the production didn't have a tank, so they built one around a car or truck chassis, and neglected to animate the tracks. They also neglected to insert the sound of a tank going by.