‘I’m glad this question was asked. All too often, we only hear and talk about impressive numbers of tanks, guns, men and dramatic decisions to transfer or redeploy them from one place to another to prepare for an upcoming gigantic counter-offensive or relieve attempt. But we don’t really pay attention to how they were moved over thousands of miles.
A few days after the Red Army launched Operation Bagration in June 1944, Hitler transferred the 12th Panzer Division from Army Group North to the 9th Army in the south to stem the advance of General Rokossovsky’s 1st Belorussian Front. This division was under-strength at the time but it still required 53 trains to move its men and vehicles.
In the book “Blitzkrieg”, author Len Deighton notes that a full-strength panzer division transported by railway needed no less than 80 trains, each train with up to 55 wagons.
This knowledge was particularly useful in estimating enemy strength. In 1944, members of the French Resistance working as railwaymen were able to report to Allied command that the 12th SS Panzer Division “Hitler Jugend” in Normandy was at full-strength because, they had counted, 84 trains were needed to move it.’
Answer by , World War II fanatic, on Quora.