* Plan will span nine projects, with total length of 1,100 km
* Projects to be built over the years to 2020 - economic planner (Adds context, comments and market reactions)
SHANGHAI, Nov 28 (Reuters) - China has approved a 247-billion-yuan ($36-billion) railway plan to improve transport links between the capital Beijing, the port city of Tianjin, and the neighbouring province of Hebei, part of plans to integrate the three areas into a mega-city.
The plan will span nine projects that total 1,100 km (683 miles) in length, the country's powerful economic planner, the National Development and Reform Commission, said in an online statement on Monday.
The projects will be built over the years to 2020, and are part of a wider plan that will stretch to 2030, it added.
The current population of the three areas is estimated at around 110 million, and by the time the plan is complete, the so-called Jing-Jin-Ji project will span 212,000 sq km (82,000 sq miles), or more than twice the size of South Korea.
The expanding railway networks have cut commute time in the region significantly, said Steven McCord, research head at real estate service firm Jones Lang LaSalle (JLL).
"It was not possible to go all the way from Beijing to Binghai and that's a one-hour trip now. It's now also possible to go between Tianjin and Tangshan in less than 30 minutes, which was previously several hours' drive," he said.
"I think there are few places in the world that have that kind of integration. It has made it much easier to do business."
The news helped push up shares of firms that stand to benefit from the plan.
Shares of China State Construction Engineering Corp soared 10 percent in Shanghai trading, while China Communications Construction Co surged 6.5 percent.
Shares of China Railway Construction Corp rose 5.5 percent and China Railway Group Ltd gained 4 percent. ($1=6.9018 Chinese yuan renminbi) (Reporting by Brenda Goh, Ryan Woo and Yawen Chen; Editing by Michael Perry and Clarence Fernandez)