Line 4 has a total of 43 stations and a length of 40.5 kilometers divided into two routes, called the North and South routes, and goes mainly through Mexico City's downtown towards and from Mexico City International Airport.

[1] Construction of Line 4 started on July 4, 2011 and it was inaugurated on April 1, 2012 by Marcelo Ebrard, Head of Government of the Federal District from 2006 to 2012.

[5] Buenavista to Terminal 2 (North route) Buenavista to San Lázaro (South route) Buenavista to San Lázaro (North route) Pantitlán to Hidalgo[6] Alameda Oriente to Hidalgo Line 4 services the Cuauhtémoc and Venustiano Carranza boroughs.

Mercado de Sonora, La Merced, Mercado Ampudia,[h] Las Cruces Norte and Museo de la Ciudad stations were relocated southbound due to traffic jams caused by their location in the market area of the historic center of the city.

[22][23] Conexión Centro-Aeropuerto, SA de CV (CCA) is the sole operator of Line 4.