Transports Metropolitans de Barcelona (TMB) has begun operating a trial service without passengers on a 20 km section of the new L9 automated metro line.
It marks a significant milestone in the testing of the line, which will connect Barcelona-El Prat Airport and the University of Barcelona.
The current test phase is replicating similar service frequencies and conditions as will be used when the line goes into commercial service in February.
The line, which includes 15 new stations, will be fully automated and is roughly the same size as the longest line on the network, L1.
L9 currently only runs between Can Zam to Sagrera stations. The new southern extension, which will eventually be linked to the existing L9 route by a central section, includes stations at airport terminals T1 and T2, plus links to L1, L5 and L3.