The Urquiza Line is a 26 km (16 mi) suburban electric commuter rail line in Buenos Aires, Argentina, operated by the Buenos Aires Underground operator Metrovías. It runs from the Federico Lacroze terminus in the neighborhood of Chacarita, to General Lemos terminus in Campo de Mayo district of Greater Buenos Aires, completing a total journey time of 46 minutes. The line uses third rail current collection and, at present, is used by an average of 75,400 passengers daily. The line operates 20 hours a day, 7 days a week at 8 to 30 minute intervals. This suburban line runs on track once operated by General Urquiza Railway before railway privatisation.

In earlier times the line was planned to run into the centre of Buenos Aires, through a long tunnel. But when the tunnel was finally built in 1930, it was taken over by the Underground system as part of Line B, and as a result, suburban passengers had to change at Federico Lacroze, named after its builder, about 6 km (3.7 mi) from the centre. The ramp connecting the Urquiza Line to Line B still exists, though it is only used for maintenance purposes. Today Federico Lacroze has a direct connection to the line B underground station of the same name.

Like the Buenos Aires Underground system, the Urquiza line uses the 1,435 mm (4 ft 8 ¹⁄₂ in) standard gauge rather than the 1,676 mm (5 ft 6 in) broad gauge used in other interurban railways of Buenos Aires.

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