https://en.wikipedia.org/wiki/List_of_driverless_train_systems https://en.wikipedia.org/wiki/List_of_driverless_train_syste... The length ranking seems to be s

https://en.wikipedia.org/wiki/List_of_driverless_train_systems https://en.wikipedia.org/wiki/List_of_driverless_train_syste... The length ranking seems to be something like: Riyadh - 176 km https://en.wikipedia.org/wiki/Riyadh_Metro https://en.wikipedia.org/wiki/Riyadh_Metro Dubai - 90km, first operation 2009 https://en.wikipedia.org/wiki/Dubai_Metro https://en.wikipedia.org/wiki/Dubai_Metro London DLR - 38 km https://en.wikipedia.org/wiki/Docklands_Light_Railway https://en.wikipedia.org/wiki/Docklands_Light_Railway Shanghai is probably in the running as it upgrades: https://en.wikipedia.org/wiki/Shanghai_Metro#Infrastructure https://en.wikipedia.org/wiki/Shanghai_Metro#Infrastructure