The world’s leader in high-speed rail development is certainly China. They keep adding to their tens of thousands of miles of train track each year.
But now they are taking their high-speed train on the road. According to this article, China and India have entered into an agreement where China will develop a feasibility study for creating a rail system between the two countries. When completed, the rail line will include over a thousand miles of track.
No doubt India is very comfortable with China paying for the study. The difficult part, however, will be when the study is complete and the nations have to discuss who will pay how much for the rail lines and trains. It will be quite an impressive feat for both countries if they actually make this happen.