Changsha trials low-speed maglev rail line

China's first home-developed low-speed maglev rail had a trial run on Saturday in Changsha, Hunan province, marking the nation becoming the fourth in the world to master medium- and low-speed maglev rail technology, joining Germany, Japan and South Korea.

The line, which stretches 18.5 kilometers and links the Changsha south railway station with the local airport, is the longest of its kind in the world. More than 90 percent of the track is built on bridges.

The line allows maglev trains to run at a maximum speed of 100 km/h. The trains, each of which is 48 meters long, have three carriages each and can carry a maximum of 363 passengers .

Industry insiders said the project is not only a milestone in the advancement of China's maglev technology, but will also help build a transportation hub in central China.

Low-speed maglev lines differ, in terms of motor structure and power supply, from high-speed maglev lines, such as the Shanghai maglev train that started operation in 2003 and runs at more than 400 km/h, said Yan Juping, assistant director of China Railway Siyuan Survey and Design Group, the contractor for the Changsha project.

He said low-speed maglev trains are suitable for mid-volume urban transportation, as they produce little noise or vibration, and feature rapid acceleration and deceleration, strong climbing ability and are environmentally friendly.

Zhang Kunlun, leader of the low-speed maglev train research and development team at Southwest Jiaotong University, said the team had found "the right path of industrialization for low-speed maglev technology in partnership with companies".

The university started its maglev rail research some 30 years ago. It and CRRC Zhuzhou Locomotive Co are the key technology providers for the line.

"The maglev control system, for example, must guarantee the train's steady movement in all conditions, whether it's in the depot, on straight lines, curved lines or slopes. We need to combine theories and practice to achieve that," he said.

The train is suspended 8 mm above the rail, thanks to 20 stabilizers under each carriage, which involves many different technologies including system design, electromagnetic compatibility, control theory and control algorithm, Zhang said.

The gap sensors work thousands of times each second, detecting the rail and slope conditions and track joints, to tell the control system how to make adjustments.

zhangzhao@chinadaily.com.cn

(China Daily 12/30/2015 page17)