Employees of CRRC Changchun Railway Vehicles Co finished the deep maintenance of the first subway train in Mecca, Saudi Arabia, on Thursday.

The company, which is based in Changchun, Jilin province, provided the first subway trains to the Mecca Metro line in 2010.

The 18-kilometer line, with nine stops connecting major holy sites related to the annual Hajj pilgrimage, is operated during the event annually to ease pilgrim traffic. It is the world's longest metro train with a capacity of nearly 5,000 passengers.

So far, it has safely transported more than 20 million people, alleviating road traffic congestion during the annual event and winning widespread praise from residents.

A workshop for deep maintenance of subway trains is located in a depot in Arafat, Saudi Arabia. [Photo provided to chinadaily.com.cn]

"After years of operation, the trains need deep maintenance, including checking key systems, replacing worn parts and reassembling and debugging the vehicles," Wang Changhong, the project manager, told China Central Television.

Last year, CRRC won a bid to provide deep maintenance services for Mecca Metro and completed the upgrading and renovation of the depot.

Deep maintenance of all trains on the line is expected to be completed by the end of 2024.

Zhang Siyu contributed to this story.

A subway train runs on the Mecca Metro line. [Photo provided to chinadaily.com.cn]