A train runs past the Badong station along the Yichang-Wanzhou railway in central China's Hubei Province, Dec. 22, 2010. The Yichang-Wanzhou railway, linking Yichang in central China's Hubei Province and Wanzhou in southwest China's Chongqing Municipality, started operation Wednesday. The 377-kilometer-long railway, considered to be China's most difficult and expensive to build, snakes through 159 tunnels and 253 bridges in southwestern China's mountainous regions. [Xinhua]

A railway considered to be China's most difficult and expensive to build started operation Wednesday.

The maiden journey began at 10:18 AM, when a train carrying more than 900 passengers left Enshi Station, Hubei Province, for a two-hour journey to Yichang City.

"We used to pay 100 yuan (US$15) for a one-day bus trip to Yichang before. Now, 30 yuan can get us there in two hours," said Zeng Mingquan, 58, who took his grandson to the launch ceremony.

Wednesday's maiden trip covered more than half the 377-km route linking Yichang to Wanzhou District, in neighboring Chongqing Municipality.

Five trains will run the full length Thursday and more trains will be added on Jan. 11 to bring the railway into full operation.

It took about 50,000 workers seven years to dig and complete 159 tunnels and build 253 bridges through a stretch of mountains on the eastern edge of the Yunnan-Guizhou Plateau for the project.

The length of track that runs through bridges and tunnels accounts for about 74 percent of the line's total.

In the most extreme case, it took almost six years to drill a tunnel through Qiyue Mountain due to complex and dangerous construction conditions.

Workers overcame the karst terrain, molten lava, subterranean rivers, fault zones, stress areas, coal and gas layers, and many other geological challenges, said Hu Ziping, chief designer of the railway.

The line, involving 22.7 billion yuan (US$3.41 billion) in total investment, is also China's most expensive railway in terms of cost per kilometer.

It cost about 60 million yuan to build each kilometer, compared with 29 million yuan per kilometer for the Qinghai-Tibet Railway, said Zhu Pengfei, a senior project leader, who also worked on the construction of the Qinghai-Tibet Railway.

The Yichang-Wanzhou railway will cut trips between Chongqing and Wuhan, capital of Hubei, from 22 hours to just five hours. Travel times from other central or east China cities to southwest China will also be significantly shorter, bringing new opportunities to residents who live in the steep and remote mountains.

"It is hoped it will help boost agricultural, industrial, tourism and commercial exchanges and set an example for future railway projects in other mountainous regions in the country," said Wang Jianzu, vice director of the Development and Reform Commission of Hubei.

The idea of building a railway in the landlocked mountainous region was initiated in 1903 during the Qing Dynasty (1644-1911), but was abandoned later due to war and financial problems.

The government resumed a survey for the project in 1994. Construction began on Dec. 1, 2003, and finished on Aug. 18 this year.