Buenos Aires Underground 100 Series

The 100 Series are a series of underground railway cars manufactured by Alstom in Brazil and Argentina for use on the Buenos Aires Underground. They are used on Line D, serving alongside some 300 Series and formerly Fiat-Materfer cars, and since 2019 some units have also been used on Line E. The 100 Series was initially purchased for Line A to replace the ageing La Brugeoise cars, but ended up replacing the slightly newer Siemens-Schuckert Orenstein and Koppel cars, which were allocated to Line D instead. The original purchase was 80 cars for 16 five-car trains, because of the shorter platform length on Line A, and 16 more cars were bought up to 2009, making 96 cars and allowing six-car trains. In 2015 the cars began a mid-life refurbishment to add air conditioning, better lighting and new upholstery. Despite a successful service life they are the noisiest cars on the network, and in 2024 Line D was adapted to use communications-based train control, requiring the fleet to be adapted.