A building of the Geely Auto Research Institute is seen in Ningbo, Zhejiang province, China August 4, 2017. REUTERS/Aly Song

BEIJING (Reuters) - Chinese automaker Zhejiang Geely Holding Group [GEELY.UL] said on Tuesday it signed an agreement with China Aerospace Science and Industry Corp (CASIC) [SASAAI.UL] to jointly develop “supersonic” trains in the country.

The strategic framework agreement aims to combine two technologies – magnetic levitation to eliminate ground friction, and vacuum tubes to reduce air resistance – to achieve a “hypersonic” mode of transportation, Geely said in a statement.

China runs the world’s longest high-speed rail line and is looking to build its own supersonic transport network.

State-owned CASIC, one of China’s major space contractors, has said it is working on a system that can shuttle trains at a maximum speed of 1,000 kph (620 mph) and studying technologies that could go as fast at 4,000 kph in the future.

Hangzhou-based Geely and CASIC will “pool their capabilities”, the statement said, but it did not give details on their investment in the joint effort or a timeframe.

“Technologies developed through the realization of supersonic trains will help Geely Holding advance the fields of new energy vehicles, automotive safety, and new material science,” the statement said.

The agreement was signed at an aerospace industry show in the southern Chinese city of Zhuhai.

Geely Holding is one of China’s five biggest automakers. It holds a major stake in Germany’s Daimler (DAIGn.DE) and owns Sweden’s Volvo Cars, as well as the company that makes London’s black cabs.