Line 1 is the oldest of the metro lines in
Budapest, having been in constant operation since 1896. The initial section ran between
Gizella tér station (now
Vörösmarty tér station) and
Aréna út station (now
Hősök tere station) and served an intermediate station under Deák Ferenc square. This original station was constructed with two side platforms, at a depth of just . The approach to the station included a sharp curve disctated by the original layout of the square. In the 1950s and in preparation for the planned line M2 of the metro, the route of the M1 line under the square was diverted in order to ease the sharp curve. This diversion left an long section of the original tunnel empty and walled off. In the end, line M2 did not open until the 1970s, but in the 1960s further preparatory work led to the creation of a large-scale pedestrian underpass system under the square, which called in question the fate of the section of abandoned tunnel. At first it was planned to fill it in, but then it was suggested that a metro exhibition be organized in it. As the eventual result of this suggestion the new museum was created in the rebuilt tunnel. The museum opened on 26 October 1975. It was renovated in 1996, the 100th anniversary of the opening of the railway. ==Collection==