Yea, but as I was told, it correlates to the current population distribution that's too heavily concentrated in China Proper.
China's population density correlates closely with rainfall, Western China is too dry to support a large population. Eastern China not only has significantly more rainfall, it also benefits from rainwater flow from the highlands of Western China. The only way I see that changing with any significance is with the 红旗河 project. It is projected to eventually increase western China's population by over 100 million, especially in Inner Mongolia, Gansu, and Xinjiang.
The terrain in Tibet, Qinghai, and mountain regions of Sichuan and Yunnan are too rough to support a dense transportation network (it is expensive to built roads and rail lines there), thus would mostly have a few main lines.
How will these long railways effect on your cities ? Is there a study on this subject ?
I want to know more about population and economy of target cities .I'm big fan of high speed trains
Not sure about studies but inter city HSR is giving rise to suburbs in China and maintaining the economic competitiveness of large cities. Some people now live 50-100km from major economic centres and can commute to work in these economic centres with ease on slower intercity hsr (200-250 km/h). This is the trend around Beijing and Yangzte river delta. Eventually this is projected to give rise to large interconnected economic clusters, made possible by rapid transport. Rapid transit facilitates outward investment flows and improves capital efficiency.
The three economic mega regions China is currently trying to create is Jing-Jin-Ji/JJJ, Yangtze River delta/YRD , and Pearl River delta/PRD. Each region is composed of sub units that are growing outwards, eventually it will integrate/absorb neighbouring mega regions. Jing-Jin-Ji for example is the outgrowth of Beijing and to a lesser extent Tianjin. Many commuters now live in the region between Beijing and Tianjin as real estate is cheaper there and can commute to Beijing in 20-25 minutes on G class trains. This serves to reduce property price spikes in Beijing and provide investment (in many sectors) in peripheral regions. Eventually Hebei province will absorb the divestment from Beijing and create a mega-region called Jing-Jin-Ji with about 100-120 million people and an transport circle of 1 hour on HSR with Xiongan New Area as the geographic center.
http://english.ctrip.com/trains/schedule/langfang-to-beijing/
During growth phase of JJJ, ongoing development of Shandong and Liaoning will also take place. These regions will be integrated with more transport links to create the Bohai economic rim surrounding the Bohai bay. A major project in this integration will be the under sea tunnel connecting Dalian and Yantai.
https://en.wikipedia.org/wiki/Bohai_Strait_tunnel
Other economic regions will experience a similar integration process. As technology progresses, the commuter circle would get progressively larger. I am not sure about the practicality of this as a commuter transport but eventually by mid-century it would be possible for China to have a 1-2 hour transport circle encompassing nearly the entire country's population and geography with high speed maglev trains.
These regions are not a continuous mega city but a cluster of cities that are easily accessible to each other.