Buenos Aires Underground 100 Series

100 Series
A 100 Series train on Line D, before mid-life refurbishment
Manufacturer	Alstom
Family name	Alstom Metropolis
Constructed	2001-2009
Entered service	2004
Number built	96
Number in service	96
Formation	6 cars per trainset
Operator(s)	Buenos Aires Underground
Line(s) served
Specifications
Car body construction	Stainless steel
Doors	4 per side
Track gauge	1,435 mm (4 ft 8 1⁄2 in)

The 100 Series are a number of underground cars manufactured by Alstom in Brazil and Argentina for use on the Buenos Aires Underground. They are used exclusively on Line D of the network, where they make up the vast majority of the fleet, serving alongside Fiat-Materfer cars.

The 100 Series was initially purchased for use on Line A to replace the ageing La Brugeoise cars, however they ended up replacing the slightly newer Siemens-Schuckert Orenstein & Koppel cars which served on Line D instead.

Originally, the purchase consisted of 80 cars for a total of 16 trains made up of 5 cars each, due to the shorter platform length on Line A. However, 16 more 100 Series cars continued to be purchased in that decade up until 2009, making a total of 96 cars and allowing each train to have 6 cars, making full use of the line's platforms.

In 2015 the cars began to receive a mid-life refurbishment, primarily to add air conditioning, but also incorporating more minor aesthetic differences to the interior such as improved lighting and new upholstery. Despite enjoying a successful service life, they are also the noisiest cars on the network.

New Alstom cars Series 300, are set to replace the Fiat-Materfer cars and serve alongside the existing 100 Series cars in 2017-2019.