True, but the Russians had their own production problems too, namely the loss of nearly the entire industrialized area of their country to the enemy in 1941. The great virtue of the T-34 was that it was so simple to manufacture that it could be built in numbers in the ad-hoc, open-air factories the Russians set up east of the Ural Mountains, and maintained even in facilities directly under enemy attack, like the famous Tractor Factory in Stalingrad (http://en.wikipedia.org/wiki/Volgograd_Tractor_Factory).