Original line

The Line 1 was the first line of the Madrid Metro, and was inaugurated on 17 October 1919. It was opened to the public on 31 October 1919. It originally ran from Cuatro Caminos and Sol, containing 6 intermediate stops: Red de San Luis (now Gran Vía), Hospicio (now Tribunal), Bilbao, Chamberí, Martinez Campos (now Iglesia), and Ríos Rosas.^[3]

The original line was extended from Sol to Atocha in 1921, then further to Puente de Vallecas in 1923.^[4] It was extended from Cuatro Caminos to Tetuán in 1929.^[5]

Early extensions

The line was expanded from Tetuán to Plaza de Castilla in 1961, and from Puente de Vallecas to Portazgo in 1962.^[6]

Between 1964 and 1966, station platforms were extended from 60 metres (196 ft 10 in) to 90 metres (295 ft 3 in) in order to allow 6-car trains, due to heavy increasing passenger flow. This resulted in the closing of Chamberí station, whose platforms could not be lengthened due to it being located on a sharp curve near Iglesia station. The old Chamberí station, however, was reopened to the public in 2008 as part of the Madrid Metro's Platform 0 project, now functioning primarily as a historic exhibition.^[7]

Recent improvements

In recent years, the line has been extended both north and south. Firstly, in 1988 Atocha Renfe was added between the stations of Atocha and Menéndez Pelayo to serve the new long-distance rail station of Atocha. On 1 April 1994, it was extended from Portazgo to Miguel Hernández and on 4 March 1999 from Miguel Hernández to Congosto.

In 2007, the line was extended to Pinar de Chamartín in two stages. First, on 30 March 2007, the line was extended from Plaza de Castilla to Chamartín, which provides interchange with Line 10 and Renfe services. The new metro complex has line 1 and in the future, line 11 on the lower level and line 10 on the upper level. On 11 April 2007 the extension to Pinar de Chamartín was completed. Here, there is interchange available to Line 4. There are two side platforms for arrivals and an island platform for departures. In May 2007, interchange to Metro Ligero 1 was available, which terminates one level higher.

On 16 May 2007, the line was extended south from Congosto to Valdecarros with two intermediate stations.

Line 1 was closed for reforms from 3 July 2016 to October 2016. 25 of the 33 stations were closed for a €70 million refurbishment project meant to modernize the line, the oldest in the system, and repair tunnel linings and replacing power cables. Replacement buses were offered to patrons during the closure.^[8][9]