The system started as a 134-kilometre (83 mi) line between Santiago and San Fernando, unifying between them the city of Rancagua and 23 other towns in the Metropolitan and O'Higgins regions.

The services were eliminated in 1979 by the military dictatorship of Augusto Pinochet, because of low profitability and the economical and administrative reformulation process that the state was having during those years.

After the fall of the military dictatorship, and with the return of democratic rule in 1990, pollution in Santiago became a health priority issue for the new authorities.

In order to avoid collapse in the public transport, the government decided to create an improvised commuter rail service to connect Santiago with Talagante in the west, and Rancagua in the south.

In 2006, given the crisis inside EFE after a corruption scandal that led the company to almost bankruptcy, it was decided to empower the most profitable services in order the national rail system.

The Metrotren line received a complete renovation in communications, electrification, signaling and station infrastructure, as well as the rolling stock was painted orange in order to facilitate the use in other EFE services like Biotren.

During that year, the first administration of Michelle Bachelet left planned an express service to Rancagua, in order to reduce travel time to 55 minutes.