The Ferrocarril Suburbano de la Zona Metropolitana de México (Suburban Railway of the Mexico City Metropolitan Area) is an electric regional rail system in Mexico City. It is also known as Valley of Mexico Suburban Rail System and colloquially referred to as El Tren Suburbano.
The initial line covers a route measuring 27 kilometers from Mexico City's Buenavista Station north to Cuautitlán, in the State of Mexico. This initial section, which began commercial service on June 1, 2008, cost US$706 million to build, with the Mexican Federal Government contributing 55% of this investment. The line is projected to carry 100 million passengers annually. From the period of June 1, 2008 through July 7, 2008, the service carried one million passengers, or an average of approximately 30,000 passengers per day, which is a rate far below the annual projections. Trains are scheduled every 6 minutes during peak hours.
The inaugural demonstration trip of the service from Buenavista to Lechería station and back again was made by the President of Mexico, Felipe Calderon Hinojosa, and the Governor of the State of Mexico Enrique Peña Nieto with President Calderon acting as the train's engineer.
The line was built on an existing railroad right of way. However, inside Mexico City itself on the approach to Buenavista Station, a considerable amount of grade separation, including below-grade excavation and new bridges was necessary due to high density and traffic congestion. The construction elicited complaints by some Mexico City residents who objected to having their neighborhoods split by the rail line, but overall the public has supported the project.
On August 24 2005, CAF (Construcciones y Auxiliar de Ferrocarriles, S.A.) obtained a 30 year concession to supply rolling stock, build and operate the Tren Suburbano. The trains used on this service are electric trains built by CAF and are similar to the series 2000 trains of the Companhia Paulista de Trens Metropolitanos of São Paulo,Brazil
Authorities hope to extend the system as far as it is practical to do so (the current long range plan is for 242 kilometers of lines), in order to reduce Mexico City's heavy road traffic congestion and air pollution. In most cases the system will follow existing rail lines, however grade separations similar to the ones done on the initial segment may be necessary.