First we have to understand, that Czarist Russia is often unfairly portrayed as completely backwards and out of its time.While in some ways this is the case, one must also say that Russia a absolute world power that had the largest army in the world. The Regime was capable of fighting WW1 mostly with weapons they produced themselves.

After the the revolution and the civil war, you have group in power that is dedicated to centralization of power and industrialization. Sadly for them however the peasant revolution has captured all the land and the newly free farmers, did not really like the idea of giving up grain for essentially free.

Lenin was forced to install a new program called the NEP (New Economic Policy). That introduced most importantly that peasants could sell their grain. The problem is of course that you can not massively invest in industrialization when you have to spend all your money on food.

The answer was collectivisation, but that was hard to implement. Stalin emerged as a leader and had the willpower to actually go threw with it. It was a long and brutal struggle that weakened the USSR but by the end of it political control over all peasants was established.

By this point Stalin has the most top down regime that has ever existed, full control over all workers and peasants. Now he can throw his full power behind industrialization and development of natural resources.

Heavy industry specially for military materials was the most important, not consumer goods. Imagine a hole society mobilised, not to mention 100000s of prisoners put to work.

Combined this with the inflow of tech and material in WW2, by the British and Americans. This combination gives you a country that has lots of people, lots of resources, modern technology and a strong centralized state that controlled it all.

Edit: I would want to point out that this is not quite as special as some people think. Also the major effort was to make the nation a superpower, while other nations just want to enrich their own people.