China is planning to connect all provincial capitals by high-speed railway, and all trips to Beijing, save those from Urumqi and Lhasa, will be no longer than eight hours, said a senior railway expert.

Wang Mengshu, an academician of the Chinese Academy of Engineering, confirmed a recent report by The Beijing News that an undersea high-speed railway tunnel under the Bohai Gulf will be built, part of a network that will connect Northeast China and South China's Hainan Province, extending 5,700 kilometers in 11 provincial regions.

Wang told the Global Times on Monday that the nationwide high-speed railway network will expedite provincial exchanges.

The undersea high-speed railway tunnel, if realized, would run from Dalian, Northeast China's Liaoning Province to Yantai, Shandong Province in a mere 40 minutes, a great improvement from the current six-hour trip, the Guangzhou-based 21st Century Business Herald reported on Friday.

Zhao Jian, a professor with the School of Economics and Management at Beijing Jiaotong University, however, questioned the comparative advantage of inter-provincial railways over other means of transport.

"It is internationally believed that a distance of 500 kilometers is to the best advantage of high-speed railways and a distance of 1,000 kilometers is the maximum, but the distances between big Chinese cities are usually more than 1,000 kilometers," he told the Global Times.

Zhao chose the 1,300-kilometer-long Beijing-Shanghai high-speed railway as an example. There are more trains between Beijing and Jinan along the line, at a distance of around 500 kilometers, than between Beijing and Shanghai, while the number of flights between the two biggest metropolises in China has not decreased, said Zhao.

He said that passengers prefer planes for longer trips since high-speed train fares are not cheaper than air fares at that distance.

Wang argued that the undersea high-speed railway will drive economic development in the northeastern region and meet the huge demand for energy resources from coastal cities.

"In addition to the coastal regions, China should also develop northwestern, northeastern and southeastern parts to be gateways as Central and Western Asian countries serve as large energy exporters for China," Wang added.

However, Zhao noted that high-speed trains cannot provide freight services and energy reserves in the three provinces in Northeast China are low. Even if trains are able to carry goods, the inadequate passenger flow and freight volume from the region will put high-speed railway under great pressure to recoup its enormous building costs, said Zhao.