The debut of the Beijing-Guangzhou high-speed railway on Wednesday marked another significant step in China's plan to develop a high-speed rail network.

With the opening of the line, the world's longest high-speed rail track, China now has more than 9,300 km of high-speed railways in operation. Below are facts about the country's high-speed railway development:

The State Council, or China's cabinet, approved the Medium and Long-term Plan for Railway Network in 2004, paving the way for the country to start development of high-speed railways -- railroads capable of accommodating trains with a traveling speed of 200 km per hour and beyond.

High-speed trains traveled for the first time on April 18, 2007, when bullet trains running at 200-250 km per hour were put to use on several tracks, including the Beijing-Harbin, the Beijing-Shanghai and the Beijing-Guangzhou lines.

The country's first high-speed railway, linking the Chinese capital Beijing and the neighboring port city Tianjin, was inaugurated on August 1, 2008, with trains traveling at a speed that could reach 350 km per hour.

An adjusted version of the Medium and Long-term Plan for Railway Network came into effect on October 31, 2008. According to the plan, the total operation mileage of the country's express passenger railways will exceed 50,000 km by 2020, covering almost all Chinese cities with a population of 500,000 or above.

The country's backbone high-speed rail network will be comprised of four north-east lines and four east-west lines, according to the plan.

The four north-east railways will connect Beijing with metropolises like Shanghai and Guangzhou as well as the northeastern cities of Shenyang, Harbin and Dalian. They will also link southeastern coastal cities such as Hangzhou, Fuzhou and Shenzhen.

The east-west lines will bridge the Beijing-Guangzhou and Beijing-Shanghai high-speed routes and extend the network to western cities like Xi'an, Lanzhou, Chengdu, Chongqing and Kunming.

On Dec. 26, 2009, the 1,069 km-long Wuhan-Guangzhou high-speed railway was put into service. It was China's first long-distance high-speed rail track.

On Dec. 3, 2010, a CRH-380A train set a new speed record of 486.1 km per hour on a test run on the 1,318-km Beijing-Shanghai high-speed railway, which officially started operation on June 30, 2011.

On July 23, 2011, a high-speed train slammed into a stalled train near the eastern city of Wenzhou, resulting in 40 deaths and 172 people being injured. The accident, which was blamed on faulty signaling equipment and mismanagement, led to a nationwide rail safety check, speed reduction for bullet trains and stagnation in high-speed rail construction.

The country cautiously resumed construction and operation of high-speed railways this year. Fixed-asset investment in railways rose 3.1 percent year on year to 506.97 billion yuan ($81.1 billion) during the first 11 months of 2012, according to Ministry of Railways data.

The State Council adopted the 12th five-year plan for transportation system development in March this year, which plans for more than 40,000 km of express railways by the end of 2015.