Railroads

Germany's invasion of the Soviet Union foundered not on Soviet resistance alone, but on an 85mm gap between German and Russian railroad gauges. The logistics of Barbarossa reveal how infrastructure determines strategy.

Railroads promised to solve the eternal logistics problem—moving supplies faster than any horse-drawn wagon. But in both the American Civil War and the Franco-Prussian War, commanders discovered that rails created as many problems as they solved.

The largest military operation in history was crippled not by Soviet heroism alone, but by a 89mm difference in railroad gauge width that made German supply lines progressively useless as the advance continued.