The Fiat-Materfer Buenos Aires Underground rolling stock was built by the Argentine company Materfer - then a subsidiary of Fiat Ferroviaria - beginning in 1980 and continuing on through that decade.

It was originally conceived to standardise the diverse rolling stock of the Buenos Aires Underground with the use of one model throughout all the lines.

However, with the economic and political turmoil faced in the country during and following the collapse of the National Reorganisation Process junta in 1983, its production ended up being far more limited.

[1][2] Over the years, the cars have seen cosmetic upgrades, as well as technical ones, such as the incorporation of Automatic Train Protection, the new Line H, and ability to play pre-recorded messages through its speakers, a feature which, unusually, was left out at the time of production.

[11] Ironically, the line had also been converted to 1500 volts that same year to incorporate the new CNR trains so the easy 1100 V to 1500 V conversion which the Fiat-Materfer cars were designed to have was ultimately never needed.