Automatic train operation (ATO) is an operational safety enhancement device used to help automate operations of trains. Mainly, it is used on automated guideway transits and rapid transit systems which are easier to ensure safety of humans. Most systems elect to maintain a driver (train operator) to mitigate risks associated with failures or emergencies.
Many modern systems are linked with Automatic Train Control (ATC) and in many cases Automatic Train Protection (ATP) where normal signaller operations such as route setting and train regulation are carried out by the system. The ATO and ATC/ATP systems will work together to maintain a train within a defined tolerance of its timetable. The combined system will marginally adjust operating parameters such as the ratio of power to coast when moving and station dwell time, in order to bring a train back to the timetable slot defined for it.
According to the International Association of Public Transport (UITP), there are five Grades of Automation (GoA) of trains:
Many railways are planning on using ATO. The Delhi Metro officials have stated that driverless trains with advanced features will run on the Botanical Garden - Kalkaji corridor with trial runs planned for the last week of July 2016 and the trains being operated on the route from August 2016 onwards. Initially, drivers will be deputed to operate the trains but they will be gradually withdrawn said a metro official. ATO was introduced on the London Underground's Northern line in 2013 and will be introduced on the Circle, District, Hammersmith & City, and Metropolitan lines by 2022. Although ATO will be used on Crossrail and Thameslink, it has not yet been implemented on UK mainline railways. The Toronto Subway and RT is undergoing signal upgrades in order to switch to have the system running on ATO over the next decade. The U-Bahn in Vienna gets an ATO in 2023 on the new U5 line.