Grades of Automation (GoA)
Grades of Automation (GoA) is the IEC 62290 scale for how much of train operation is automated: GoA0 (on-sight), GoA1 (manual with protection), GoA2 (semi-automatic, driver present), GoA3 (driverless with attendant) and GoA4 (unattended). Higher grades shift safety enforcement from the driver to networked control systems.
How it works
Each grade defines which functions remain with a human and which are automated. At GoA2 the system drives between stations while a driver handles doors and disruptions. At GoA3 there is no driver but an attendant on board can take over. At GoA4, unattended train operation (UTO), the train runs with no staff on board and all functions, including driving, door control, obstacle detection and incident handling, are automated.
GoA is most commonly applied to metro lines running CBTC, where GoA4 operation has been in service for decades.
Why it matters for security
As the grade of automation rises, the human safety backstop is removed and more decisions depend on the control network, the onboard controllers and their communication links. A cyber incident affecting a GoA4 line has fewer manual fallbacks, which raises the importance of monitoring and defending the automation systems themselves.
Related solution
Securing CBTC systems without disrupting automation
Protecting highly automated metro lines while preserving performance and safety assurance.
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