True, but to be correct I think the focus is not so much on the Soviet Railroads as it should be on the lack of Soviet roads. In the supply chain during Barbarossa the worst bottleneck was river crossings for the Wehrmacht in general and the supply columns specifically. The Germans had plenty of bridging equipment but the real problem was the access area to the bridge and exit from it quickly became overused and barley passable (undeveloped, unsurfaced muddy mess with long waits). So even if the rail was more efficient or efficient enough, any offensive beyond Smolensk is going to have a shorter leash than the previous offensive efforts. When Barbarossa began the Germans had an established logistical base to work from (Poland/Prussia/Romania) which made the resupply runs shorter for the supply columns of trucks. In addition and more importantly the Germans had the "handkoffer" which was containerized fuel (Jerry cans, barrels, etc.) which accompanied them as they went and enabled them to advance as far as they did as fast as they did. However, once that was used it could not be replenished far forward in the field and therefore the same type of advance up to that point could not be replicated. Any advance beyond Smolensk required a full reset and replenishment (3 weeks roughly) assuming the rail system would support it and even then it was less capable than the initial operations. That is more or less the OTL logistical plan in a nutshell and it was based upon the flawed assumptions on Soviet strength and force generation previously mentioned. If accurate Intel was available could the Wehrmacht have performed better, definately... Does that guarantee an Axis victory? No. Conversely, if the Soviets had accurate Intel the German attack would have been much more costly and not gotten near Moscow (assuming they had about 90 days to prepare).