A staff thrilled about the launching of the new bullet train at a naming ceremony in Beijing, June 25, 2017. [Photo/VCG]

Fourteen Fuxing bullet trains will serve passengers on the 1,318-km Beijing-Shanghai line starting on Sept 21, reducing the travel time to about four and a half hours, State-owned China Railway Corp, the train's operator, said on Sunday.

Currently, the trip between the two metropolises, on one of China's busiest rail lines, takes from four hours and 49 minutes to six hours, the difference arising because of varied numbers of stops being made.

China reduced its bullet trains' maximum speed to about 300 km/h in August 2011 for safety reasons.

The newest generation bullet train, the Fuxing, Chinese for rejuvenation, has been in operation since June 25. On July 27, railway authorities completed testing of the Fuxing that will permit the restoration of the maximum speed to 350 km/h on the Beijing-Shanghai high-speed line.

During their journey, the passengers have a bit more arm and leg room, and enjoy free Wi-Fi and better-placed charging plugs for phones and computers - located near the armrests instead of below the seats.

In addition, comprehensive and scientific assessments have shown the rail line meets the requirements for bullet trains run at that high speed, and, given that the ample preparations made, rail authorities and experts have guaranteed that Fuxing trains are capable of the high speed, according to the company.

"Restoring bullet trains' top speed to 350 km/h is a sign of the maturity of China's high-speed railway technologies," Liu Xu, vice-president of the Chinese Academy of Engineering, told Xinhua in a previous interview.

Fuxing trains, the product of Chinese railway standards and technologies, have improved safety, comfort and energy conservation, according to China Railway Corp.

Following their debut on the Beijing-Shanghai line, they will be put into operation in the Beijing-Tianjin-Hebei area on Monday, serving 10 stops in the region, including Tianjin, Baoding and Shijiazhuang, the company previously said.

There, Fuxing trains will run at a maximum of 300 km/h.

The longest tunnel - 8,755 meters - on the Harbin-Mudanjiang high-speed railway was expected to be finished on Sunday, marking a major step for the northeastern high-speed rail, China Central Television reported.