Travel Information about Espana and Madrid

(GMT)08 JAN 2017 GANGGU7:  One of eight stations on the Metro's first line, the Chamberí station linked the nascent system to the Plaza de Chamberí above.
Opened in 1919, this inaugural version of the Metro ran for four kilometers, from Cuarto Caminos to Puerta del Sol. However, this modest start would quickly become a popular and vital part of the urban landscape, expanding rapidly over the following decades to become one of the longest and most comprehensive metro systems in the world.
As part of this progressive expansion, the trains on line 1 were lengthened in the 1960s. This meant the end for Chamberí; built on a curve, and close to both Bilboa and Iglesia, lengthened the station's platform proved both pointless and basically impossible. Chamberí was closed on May 22, 1966. The rails, however, were not moved, nor the trains rerouted, so it served for decades thereafter as the mystery station glimpsed by passengers on trains merely passing through.

https://www.eyeonspain.com/blogs/bestofspain/16610/madrids-phantom-station.aspx