Answer:
As sad as it might be, the truth is that the transition came under Stalin. Intensive industrialization under Joseph Stalin, of both Agriculture and the production of Machinery, led them into arms production and got them competitive on the World Stage… it was Stalin who got them outdoing most of the Depression-hit Capitalist nations in the west.
But it came, of course, at a huge cost- thousands died from overwork, and massively unreasonable targets. Death and repression was the cost of such a speedy transition from poverty to power.