sentences:  It is expected that the Yonge-University-Spadina line will have OPTO implemented in 2019, and the Bloor-Danforth line will follow with OPTO in 2021.The TTC's future light rail lines will use one-person operation in conjunction with an automatic train control (ATC) system.GO Transit in Ontario operates with a conductor and engineer in the cab, as well as a conductor called a "Customer Service Ambassador" located within the train who is responsible for controlling the doors and making announcements.