2014. Routes The metro consists of four lines (M1–M4), each denoted by a different colour. M1 (yellow) runs from Mexikói út south-west towards the river. The M2 (red) line travels east–west through the city, crossing the Danube. The M3 (blue) runs in a broadly north–south alignment, interchanging with the three other lines. The M4 (green) line commences at Keleti pályaudvar and travels south-west, crossing the river, to terminate at Kelenföld vasútállomás. Metro line M1 Line 1 runs northeast from the city centre on the Pest side under Andrássy út to the Városliget, or City Park. Like Metro 3, it does not serve Buda. Line 1, the oldest of the metro lines operating in Budapest, has been in constant operation since 1896. In the 1980s and 1990s, the line underwent major reconstruction. Of its 11 stations currently served, eight are original and three were added during the reconstruction. The original appearance of the old stations has been preserved, and each station feature displays of historical photographs and information. As part of the reconstructiona Millennium Underground Museum in the old station at Deák Ferenc tér connected to the concourse. There are plans for the future extension of the line in both directions. Metro line M2 Line 2 runs east–west from Déli pályaudvar in Buda's Krisztinaváros, through the city center, to Örs vezér tere in eastern Pest. It offers connections to Hungarian State Railways at Déli and Keleti pályaudvars, to metro lines M1 and M3 at Deák Ferenc tér, to M4 at Keleti pályaudvar, to suburban railway lines 8 and 9 at Örs vezér tere, and to suburban railway line 5 at Batthyány tér. Prior to the opening of M4, it was (for more than 45 years) the only metro line that served the Buda side of the city. Metro Line 2 underwent a major reconstruction in the second half of the 2000s, with all of the track replaced and stations revamped by 2010. The entire fleet of Metrovagonmash 81-717/81-714 cars operating on the line were replaced with Alstom Metropolis metro cars by 2012. Planning of a direct connection of Metro Line 2 and the suburban railway lines with a shared new station at Örs vezér tere and the addition of a potential new underground station near Hungexpo Budapest Congress and Exhibition Center, offering another interchange point to mainline railways began in 2021. Metro line M3 Line 3 runs in a north–south direction