INFRARED rays have been installed on doors at the edge of platforms along the city's newly opened Metro Line 10 to detect any problem with the doors' closing.

Once any of the doors are found not properly closed, signals will be sent to prevent the train from starting.

"We are still testing the efficiency of this technology," said Gao Guorong, a manager with the Metro equipment department.

Line 10 is on a pilot schedule, its trains running only from 9am to 4pm.

How the newly installed doors will perform in the most crowded peak hours hasn't been tested yet, Gao said.

The infrared technology eventually might be applied to the entire subway network to reduce the chance of accidents when crowds of people squeeze into subway cars, an infrared-ray technology provider said at an international Metro exhibition held in Shanghai.