These are genuine questions. We don't have a large industrial complex, so what exactly will we be moving. The current status of our railway is in shambles due to poor maintenance and serviceability. The railway link is merely an alternative route for china to transport it's good. We'll only generate toll from it. The same way NATO supply works. We Pakistani suck at charging fees from foreigners.
The 220 million population and increasing is an incoming disaster. Lack of education and skilled workforce. 30 million children out of schools. What's the point of having such a large population?
When I was growning up in Pakistan, decades ago, I remember watching those very long "mall garis" (the freight trains" running through Karachi going in different parts of the country. If the economic activity was there back in those days, it is still there but our "democratic governments" have destroyed whatever infra we had and regressed us. Manufacturing doesn't mean you are shipping high tech stuff. It could be raw materials. agriculture products etc. You can relived all the traffic on your motorways and make them less congested.