By 1945, L-L was virtually gone! The real importing of goods was from 1942 to 1944.
Like any rail system, it is good point to point but, it is a comedy to think of a rail system that could support an army on the move! The problem with any rail system is that it is good from point to point. To go from the rail junctions to the battle area, is where you need trucks... lots of trucks.
To me the biggest surprise was the reality that 70% of L-L came into the USSR from Alaska (mostly by air transport) and through Iran!
BUT... more over, the USA nor the USSR will ever agree on the importance of L-L. If you believe the USA/UK then, we did a lot. It is not just the goods delivered but also giving technology assistance (aluminum, petroleum products, automotive production assistance, etc.) was a big boost in the capability of the USSR. If you believe the USSR then, American and the UK did not do much.
A lot of people condemn the UK for supplying the newest jets engines to the USSR. What is less known is, that if the USSR felt more secure about air defense it would be less hostile in the post war years. In that effort the USA to supplied the USSR with radar technology!
To me the biggest surprise was the reality that 70% of L-L came into the USSR from Alaska and through Iran!
To go from the rail junctions to the battle area by trucks could be done ....on very short distances,if the armies advanced,the rail roads had to advance :all German and Russian offensives had to stop because of supply problems,the same happened in september 1944 in Western Europe:when the Allies were over the Seine,the supply problems began ,and these could not be solved by the Red Ball Express .
There also is the point that tanks,trucks,artillery,ammunition...had to be transported by train.
The German AGC received in july,august,september 1941 an average of only 26 trains and 10500 tonnes A DAY,and this was not enough for some 1 million men .
The whole Ostheer needed (without bitter fighting) every day 750 trains with 30000 tonnes,to transport this from the railway junctions to the frontline,the Germans needed 30000 operational trucks,every day ,what they did not have .
As the average Russian front strength was 6 million,they would need every day 60000 tonnes,meaning a minimum of 60000 operational trucks,and I doubt they had that amount .On 1 january 1945,the Soviet front units had 300000 trucks,but only 50 % (at most) could be used to supply the units,the others had to join the advancing forces .
A total of 362,288 US L-L trucks arrived in the SU (till 20 september 1945)
Each Soviet division needed at Bagration 275 t/a day and the Soviets only had 12000 trucks to transport goods from railheads to units .
About the distances from the railheads to the units :in july 1944,the Allies had the capacity to transport 45000 tonnes of supply 50 miles r/t each day,or 90000 tonnes 25 miles (this was fairly closily with the German capacity of june 1942).The longer the distance betwen the railheads and the units,the lesser the capacity,the result being the halt of AGC in august 1941,the halt of the Allied pursuit in september 1944,the halt of the German advance to the Wolga in august 1942,etc...etc ...