Automatic train operation

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 subways 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.

Types of train automation
According to the International Association of Public Transport (UITP), there are five Grades of Automation (GoA) of trains:


 * GoA 0 is on-sight train operation, similar to a tram running in street traffic.
 * GoA 1 is manual train operation where a train driver controls starting and stopping, operation of doors and handling of emergencies or sudden diversions.
 * GoA 2 is semi-automatic train operation (STO) where starting and stopping are automated but a driver in the cab starts the train, operates the doors, drives the train if needed and handles emergencies. Many ATO systems are GoA 2.
 * GoA 3 is driverless train operation (DTO) where starting and stopping are automated but a train attendant operates the doors and drives the train in case of emergencies.
 * GoA 4 is unattended train operation (UTO) where starting and stopping, operation of doors and handling of emergencies are fully automated without any on-train staff.

Examples
The earliest ATO system on a full metro line was on the Barcelona Metro line 2 (now integrated in L5), introduced in 1961 and replaced with a more modern system in 1972. The original system used two photocells, one for acceleration and one for braking, with steel plates on the track to control train spacing and intervals. Another example was on the Victoria line of the London Underground, opened in 1968, whose ATO system was upgraded in 2013. The ATO system performed all functions of the driver except for the opening and closing of the doors: the driver pressed two buttons to start the train and, if the way was clear, the train automatically proceeded to the next station. Many newer systems are now computer-controlled, including London's Docklands Light Railway and the Central Line and Jubilee Line of the London Underground, Line 14 of the Paris Métro, Copenhagen Metro, Kelana Jaya Line of Kuala Lumpur Rail Transit System, the Washington Metro, Hong Kong MTR, Manila Light Rail Transit System, North East Line, Circle Line and the future Downtown Line of Singapore MRT, Tokyo Metro Namboku Line, Kobe Municipal Subway, a number of ART-based and VAL-based systems.

Records
A "driverless" train is defined as meeting GoA 4.


 * Longest and oldest network: Vancouver SkyTrain, 68.7 km (42.7 mi), 1985-86
 * Longest partially automatic driverless line: Lille Metro Line 2, 31.7 km (19.7 mi)
 * First partially automatic driverless line: London Underground, Victoria Line, 1968
 * First Metro with All Lines system Caracas Metro, 1983


 * Longest fully automatic driverless underground line: Circle MRT Line, Singapore, 35.7 km (22.2 mi)
 * First fully automatic driverless underground line: Paris Métro line 14, Paris, 1998

The Dubai Metro (about 70 km in the first phase, including 50 km in one line) and Singapore's Downtown MRT Line (42.0 km) are likely to take over the longest network/line and longest underground line records respectively when completed.

The future
Many railways are planning on using ATO. It has been partially implemented on the Delhi Metro with plans of full operation by 2013. ATO was introduced on the London Underground's Northern line in 2013 and the SSR Lines by 2018. Although ATO will be used on Crossrail and Thameslink, it has not yet been implemented on UK mainline railways.

Guided buses
Guided buses may be operated automatically.