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.