Hanging on - Dean Kootz

It all began when Major Kelly's Army engineers were dropped into Nazi-occupied France and ordered to keep a bridge open until the Allies arrived.
Except the mission was a secret and nobody knew they were there -- nobody except the Luftwaffe, which kept bombing the bridge ... which meant the GI's kept rebuilding it ... which meant the Luftwaffe kept bombing it ...
Which meant the tension was doing funny things to Major Kelly's men's minds ... which meant anything could happen