The AES (Automotor Eléctrico Suburbano) is an electric passenger railcar that has been in use in Chile since 1977, originally with Ferrocarril del Norte, and later for MERVAL, the Valparaiso region metro system.

There was a major accident at the town of Queronque on February 17, 1986, involving two AES units.

In the early 2000s, MERVAL has gradually introduced new UT440R (Unidad de Tren 440 Reformado) railcars, bought second-hand from Spain and refurbished.

After operating side-by-side with the AES units for a brief period, they have completely taken over passenger service on June 30, 2005.

Although the change to the sophisticated, quieter, airconditioned and technologically advanced Alstom X'trapolis units has been met with a very positive public response, there are many Chileans who feel nostalgic about the AES trains that have been part of their daily lives for decades, in the future model AES train, used service especial tourist "Train Memory".