Soon the growing Spanish railway system was dominated by two large companies: the Compañía del Norte (Northern Company), who operated the lines between Madrid and the Atlantic North of Spain from the Estación del Norte (now Príncipe Pío), the Madrid, Zaragoza and Alicante railway (MZA) who operated the lines between the capital and the Mediterranean and Andalusian cities from the Atocha station.

After the Civil War, in 1941, the ailing railway companies were nationalised and joined in the new RENFE, and the narrow gauge lines were progressively closed, the last one in 1970.

The towns around the line (Coslada, San Fernando de Henares, Torrejón de Ardoz, Alcalá itself) and some suburbs within the city of Madrid (Vallecas Villa, Vicálvaro) started to grow large bedroom communities, which relied heavily in the railway for commuting to Madrid.

At the same time, the former rural towns of Alcorcón, Móstoles, Leganés, Fuenlabrada and Getafe (and some others) started to grow as bedroom communities.

In the 1980s, services started to operate between Madrid-Chamartín and the new town of Tres Cantos, serving also the Autonomous University of Madrid campus, in Cantoblanco.

In 1989, RENFE divided its services in business areas (áreas de negocio), each one with its own symbols and livery.

[2] At the same time, a shift was appreciated in the Metropolitan Madrid area growth; the new housing initiatives moved from the northeast and southwest part of the region to the northwest.

RENFE then started an ambitious plan of growth of the Cercanías network: upgrading the 19th-century link [es] from the decaying Norte station, now renamed Príncipe Pío, to the Atocha station, through the former industrial districts just south the Madrid downtown, burying it underground from Príncipe Pío to Delicias.

[3] The next year, the rail station of Puerta del Sol in downtown Madrid, part of this second tunnel, was inaugurated.

In 2004 construction was begun on a second central line to link Atocha and Chamartín, to relieve the heavy traffic in the old tunnel (built during the 1930s and 1940s, when materials were scarce and poor).

Rather strangely for such a night-living city as Madrid, trains do not operate late at night, mostly for union and safety reasons.

As Renfe is (at the moment) a constituent of the Spanish Ministry of Infrastructure, and national infrastructure development projects during the last ten years have focused on the development of the Spanish high speed network, funding for new lines has been scarce and growth has been slow (in comparison with the rocket-paced growth of the Madrid Metro).