BEIJING - China has started building 16 new express rail projects, including a 115-km line that will cut Tianjin-Beijing travel time in half ahead of the 2008 Beijing Olympics, Xinhua news agency reported on Sunday.

Work began several days ago on the Tianjin-Beijing line, and trains with maximum speed of 300 kph (185 mph) will shorten the journey from 70 minutes to around 30 minutes, Liu Rong, director of the Ministry of Railways construction project, was quoted as saying.

China aims to have 12,000 kms (7,500 miles) of express-rail lines by 2020, linking provincial capitals and large and medium-sized cities, as well as cities in the booming Bohai Sea, Yangtze and Pearl River regions, Xinhua said.

China's State Council has also approved a feasibility study on a planned 1,318 km (818 miles) high-speed railway to link Shanghai and Beijing, a plan that has been in the works for nearly 10 years.

It would be the longest high-speed rail line in the world and would cut travel time between the two cities from around 10 hours at present to about five hours, according to the report.