The Buenos Aires Underground, locally known as Subte, is a rapid transit system that serves the area of the city of Buenos Aires, Argentina. The first section of this network opened in 1913, making it the 13th earliest subway network in the world and the first underground railway in Latin America, the Southern Hemisphere, and the Spanish-speaking world, with the Madrid Metro opening five years later, in 1919. As of 2023, Buenos Aires is the only Argentine city with a metro system.

The Urquiza Line is a 26 km (16 mi) suburban electric commuter rail line in Buenos Aires, Argentina, operated by the former 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.