http://en.wikipedia.org/wiki/Lend-Lease
Even after the United States forces in Europe and the Pacific began to reach full-strength in 1943–1944, Lend-Lease continued. Most remaining allies were largely self-sufficient in front line equipment (such as tanks and fighter aircraft) by this stage, but Lend-Lease provided a useful supplement in this category even so, and
Lend-Lease logistical supplies (including motor vehicles and railroad equipment) were of enormous assistance.
Much of the aid can be better understood when considering the economic distortions caused by the war. Most belligerent powers cut back severely on production of non-essentials, concentrating on producing weapons. This inevitably produced shortages of related products needed by the military or as part of the military-industrial complex.
The USSR was highly dependent on rail transportation, but the war practically shut down rail equipment production:
only about 92 locomotives were produced. 2,000 locomotives and 11,000 railcars were supplied under Lend-Lease. Likewise, the Soviet
air force received 18,700 aircraft, which amounted to about 14% of Soviet aircraft production (19% for military aircraft).[15]
Although most Red Army tank units were equipped with Soviet-built tanks, their logistical support was provided by hundreds of thousands of U.S.-made trucks. Indeed by
1945 nearly two-thirds of the truck strength of the Red Army was U.S.-built. Trucks such as the Dodge 3/4 ton and Studebaker 2½ ton, were easily the best trucks available in their class on either side on the Eastern Front.
American shipments of telephone cable, aluminium, canned rations, and clothing were also critical.[16]
