Passengers enter Chatswood Station of the newly-opened Sydney Metro Northwest, in Sydney, Australia, May 26, 2019. Sydney's new driverless northwest Metro opened on Sunday. (Photos: Xinhua)

Passengers take a driverless train of the newly-opened Sydney Metro Northwest at Chatswood Station in Sydney, Australia, May 26, 2019. Sydney's new driverless northwest Metro opened on Sunday.

A driverless train of the newly-opened Sydney Metro Northwest pulls into Chatswood Station in Sydney, Australia, May 26, 2019. Sydney's new driverless northwest Metro opened on Sunday.

A driverless train of the newly-opened Sydney Metro Northwest pulls into Chatswood Station in Sydney, Australia, May 26, 2019. Sydney's new driverless northwest Metro opened on Sunday.

Passengers take a driverless train of the newly-opened Sydney Metro Northwest in Sydney, Australia, May 26, 2019. Sydney's new driverless northwest Metro opened on Sunday.

Passengers wait on the platform to take a driverless train of the newly-opened Sydney Metro Northwest at Chatswood Station in Sydney, Australia, May 26, 2019. Sydney's new driverless northwest Metro opened on Sunday.