Adding to what @QinShiHuangsShlong@lemmy.ml said, keep in mind there's multiple different interests here. The bourgeoisie still make a significant amount of economic decisions in China, and they're heavily influenced by the west/capitalism. At the same time, the CPC guides those companies (either through voting shares or party connections) towards accomplishing the goals of the party.

So it is a contradiction. Should China do more to export trains instead of cars? Sure, but they're still somewhat at the mercy of the global market. And China is still the largest exporter of trains anyway.