Revealing mistake: In the opening sequence when Colonel Ryan's plane has crashed and is on fire, you can see a metal pole supporting a burning aircraft shell, not a real plane.
Revealing mistake: Obvious model train in the wide shots of the bombing of the town the train is going through.
Answer: The majority of prisoners were heading towards Switzerland through the tunnel, only a few prisoners with weapons were acting as a rear guard to hold off the German troops chasing them and buy the prisoners time to escape.
Scott215
All the prisoners were on the train. I've contended before, they didn't need to fix the track. Just leave the train on the bridge and go straight through the tunnel. That route HAD to be shorter than going around on the walkway, and they would have had a much larger head start than waiting to fix the track.
kaevanoff