Estación Museo Chamberí
Andén 0 ("Platform 0"), the so-called ghost station of Chamberí, is now a locomotive museum managed by Metro Madrid. It occupies the grand old Chamberí Station, built in 1919 and defunct since 1966. There are vintage advertisements, old maps, and other memorabilia. Tours (free) and placards are in Spanish only. Don't wait for staff to come fetch you after watching the introductory film—just head down to the platform.