High-speed trains are expected to run at an operational speed of 500 kilometers per hour or above by 2050, experts said in Beijing on Thursday.

"We will own the technology of operating trains at the speed of 500 km per hour by 2050," Zhang Shuguang, deputy chief engineer of China's Railway Ministry, said at the seventh World Congress on High Speed Rail.

Zhang made the statement when participants were asked "how fast high-speed trains will run per hour in 2050."

Among almost 2,000 participants, 42 percent said at least 500 km, 33 percent selected 500 km and only 9 percent selected 400 km.

Zhang used his own experience on a train during its test run on the Beijing-Shanghai high-speed railway, which is under construction, to prove his argument.

During the test run on Dec. 3, a CRH-380A train set a new speed record of 486.1 km per hour.

"After the speed exceeded 380 km per hour, the interaction between wheel and track did not increase obviously along with the growth of the speed," Zhang said.

"When the speed per hour hit 450 km, I felt even better than when it reached 400 km," Zhang said. "So I think in 40 years, we will reach this goal."

Ning Bin, president of Beijing Jiaotong University, echoed Zhang's remarks, saying the operational speed of high-speed rail would exceed 500 km per hour.

"The train's speed per hour is affected by the limitations of technology, economic and social benefits," Ning said.

The operational speed of high-speed trains increased to 350 km per hour in 2010 from 200 km per hour, a record Japan set in 1964.

"In the next 40 years, with the development of material science, non-contact power supply and wheel track technologies, it is possible (for the speed per hour) to increase another 150 km," Ning said.

However, other experts were cautious when forecasting the future of high-speed rail.

Norimichi Kumagai, executive director of Japan's Rail Technical Research Institute, said high-speed rail should consider factors such as technology, environment, energy efficiency and maintenance costs.

For Japan's high-speed rail, the wheel-track system was suitable for a speed of 400 km per hour. But when the speed exceeded 500 km per hour, it was better to operate magnetically levitated trains. Both could be used when the speed is between 400 and 500 km per hour, Kumagai said.

"We should evaluate depending on different situations," Kumagai said.

Antonio Gonzales Marin, chief executive officer of Spain's Administrator of Railway Infrastructure, said it was more appropriate to operate trains at a speed of 450 km per hour.

"We should consider the speed issue from the perspectives of technology, the influence it will exert on environment and energy consumption, and it depends on different countries," Gonzales said.

The seventh World Congress on High Speed Rail, with the theme "High speed rail spearheads greener transport," was held in Beijing from Dec. 7 to 9. It is the first time that a non-European country hosted such event.

Representatives of four international organizations, officials from more than 60 countries and regions as well as experts and scholars attended the meeting.