China opened the world's longest high-speed rail line on Wednesday, cutting in half the time it takes to travel from the country's capital in the north to Guangzhou, an economic hub in southern China.

The opening of the 2,298-kilometre line was commemorated by the departure of a train from Beijing for Guangzhou. Another train left Guangzhou for Beijing an hour later.

China has massive resources and considerable prestige invested in its high-speed railways program.

But it has in recent months faced high-profile problems: part of a line collapsed in central China after heavy rains in March, while a bullet train crash in the summer of 2011 killed 40 people. The former railway minister, who spearheaded the bullet train's construction, and the ministry's chief engineer, were detained in an unrelated corruption investigation months before the crash.

A man accepts a booklet while aboard China's new high-speed train. Passengers will be whisked from Beijing to the southern commercial hub of Guangzhou in just eight hours. (Associated Press/Getty Images)

Trains on the latest high-speed line will initially run at 300 km/h with a total travel time of about eight hours. Before, the fastest time between the two cities by train was more than 20 hours.

The line also makes stops in major cities along the way, including provincial capitals Shijiazhuang, Wuhan and Changsha.

More than 150 pairs of high-speed trains will run on the new line every day, the official Xinhua News Agency said, citing the Ministry of Railways.

Railway is an essential component of China's transportation system, and the government plans to build a grid of high-speed railways with four east-west lines and four north-south lines by 2020.

The opening of the new line brings the total distance covered by China's high-speed railway system to more than 9,300 kilometres — about half its 2015 target of 18,000 kilometres.