at track 4 of the
42nd Street Shuttle (right) in 1962 Many modern systems are linked with
automatic train protection (ATP) and, in many cases,
automatic train control (ATC) where normal
signaling operations such as route setting and train regulation are carried out by the system. The ATC and 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 coasting when moving and station
dwell time in order to adhere to a defined timetable. Whereas ATP is the safety system that ensures a safe spacing between trains and provides sufficient warning as to when to stop. ATO is the "non-safety" part of train operation related to station stops and starts, and indicates the stopping position for the train once the ATP has confirmed that the line is clear. The train approaches the station under clear signals, so it can do a normal run-in. When it reaches the first beacon – originally a looped cable, now usually a fixed transponder – a station brake command is received by the train. The on-board computer calculates the
braking curve to enable it to stop at the correct point, and as the train runs in towards the platform, the curve is updated a number of times (which varies from system to system) to ensure accuracy. When the train has stopped, it verifies that its brakes are applied and checks that it has stopped within the door-enabling loops. These loops verify the position of the train relative to the platform and which side the doors should open. Once all this is complete, the ATO will open the doors. After a set time, predetermined or varied by the control centre as required, the ATO will close the doors and automatically restart the train if the door closed proving circuit is complete. Some systems have
platform screen doors as well. ATO will also provide a signal for these to open once it has completed the on-board checking procedure. Although described here as an ATO function, door enabling at stations is often incorporated as part of the ATP equipment because it is regarded as a "vital" system and requires the same safety validation processes as ATP. • Eliminating human sources of errors • Increasing capacity by stronger utilisation of existing rail tracks • Reduction of operational costs.
Paris Métro reduced its operational costs in case of GoA 4 by 30%. • Increasing overall service reliability • Improving fleet management and service flexibility • Increasing
energy efficiency Accidents and incidents involving ATO While ATO has been proven to drastically reduce the chance of
human errors in railway operation, there have been a few notable accidents involving ATO systems: == ATO research projects ==