A five-step scale (GoA0–GoA4) for how much of a train's driving is automated — and, above all, whether any staff are on board at all.
🤖 This definition was generated with AI from the sources linked throughout. It has not had a complete human review — treat it as a starting point and follow the sources. How this works.
Grades of Automation, set out in the international standard IEC 62290-1, are a five-step scale for how much of a train's driving a machine does. GoA0 has no signalling protection at all. At GoA1 a driver drives, watched over by signalling. At GoA2 the train accelerates and brakes itself while a driver stays in the cab and works the doors. At GoA3 nobody drives, but an attendant rides along. At GoA4 — unattended operation — nobody is aboard.
The last step is a staffing question, not a technology one, which is why the grade lets a reader check a "driverless" headline instead of trusting it. Santiago is the cleanest case in this atlas: the CAF trains on Lines 6 and 3 were built with no driver's cab at all, so there is no staffed fallback to quietly return to. Delhi is the opposite — the "driverless" launch of December 2020 was the ribbon-cutting, and operators only came off the Magenta Line in stages between 2024 and 2025. Toronto never overclaimed: its resignalled Line 1 is honest GoA2, and what automation actually removed was the second crew member.
A high grade promises nothing about service, and it can be revoked. Busan's fully unattended Line 4 is the least-used line on its own network. Osaka put crews back aboard its automated guideway after a 1993 runaway injured more than 200 people. Washington switched its automation off within a day of the fatal 2009 Fort Totten crash and needed fifteen years to bring it back, line by line.
Added 2026-08-01 · Part of the growing Smart City Glossary