When the Nazis invaded Russia, Stalin dismantled a crapload of tank and other military production factories, along with steel production equipment and the heavy machinery that went with it by rail to safer sectors in Siberia and the Caucasus, where they were rebuilt so production could begin as soon as possible. 1300 factories were packed up from the northern industrial sectors and carried east by train into the Urals, Central Asia or Siberia. I watched a British TV series called “War Factories.” I believe it consisted of four seasons, and they covered the evacuation of the buildings, and machinery by rail. It was an amazing feat. I had never heard about it before. I know the U.S. provided many train engines and rail cars during the war.