Why did Germany face transportation problems during its invasion of the Soviet Union in 1941?

During the 1941 invasion of the Soviet Union, Germany faced severe transportation and logistical challenges that hindered its military momentum. These difficulties stemmed from several critical factors:

• Infrastructure and Gauge Differences: The Soviets destroyed or evacuated much of their rolling stock. Furthermore, the German military could not utilize the Soviet rail system effectively because Soviet railroad tracks were of a different gauge than German tracks, requiring time-consuming conversion to accommodate German rolling stock.1
• Environmental and Weather Conditions: By mid-July, heavy rainstorms turned sandy Russian roads into deep mud, which significantly slowed German wheeled transport. Later in the year, the onset of an exceptionally severe winter paralyzed German mechanized transport, tanks, artillery, and aircraft.21
• Shortage of Motorized Transport: The Wehrmacht suffered from a chronic lack of motor transport and rolling stock. Most of the invading force consisted of slow-moving infantry divisions reliant on horse-drawn wagons, which could not keep pace with the rapid advances of the armored spearheads.3
• Scorched Earth Policy: The retreating Soviet forces destroyed bridges and infrastructure, further complicating the German ability to move supplies forward.1