In 2026, the vast majority of trains worldwide are still operated by human drivers, though the industry is rapidly transitioning toward various levels of automation. Modern rail systems use the "Grades of Automation" (GoA) scale, where GoA 2 is currently common; this means the train drives itself from stop to stop, but a human driver remains in the cab to override the system and manage door operations. However, "fully autonomous" trains (GoA 4), which require no staff on board, are now standard in many metro systems like the Paris Métro Line 14, the Vancouver SkyTrain, and the newly expanded Phase II lines in Chennai. Freight rail is also seeing automation, with Rio Tinto’s "AutoHaul" in Australia operating 2-kilometer-long autonomous trains. Despite these advances, human oversight remains critical for high-speed intercity lines and complex freight networks to handle unforeseen obstacles, weather disruptions, and mechanical emergencies that AI cannot yet fully manage.