CHANGCHUN-- The CNR Changchun Railway Vehicles Co has suspended delivery of a type of high-speed train and launched a technical overhaul after a string of breakdowns.

The overhaul, targeting the company's delivered and undelivered CRH380BL trains, is expected to end in a month, a spokesman with the company, a prominent bullet train maker under the China CNR Corporation, told Xinhua on Wednesday.

Changchun is expected to manufacture 112 CRH380BL trains for the Beijing-Shanghai high-speed railway, and has already delivered 24 trains.

In late July, two CRH380BL trains abnormally stopped three times when delivered from Beijing to Shanghai.

The breakdowns were mainly caused by failures of the trains' sensors, said Zhao Minghua, the company's vice general manager.

"A train has more than 1,000 sensors to monitor components' pressure, speed and temperature. When the sensors detect any unusual conditions, they will issue an alert and make the train stop automatically," Zhao said.

The company has dispatched more than 30 technical professionals to check the trains' sensors, provided by a foreign supplier, in the cities of Beijing, Shanghai and Jinan.

"The breakdowns make us realize that we must conduct strict checks for suppliers' products," Zhao said.