The
Central line is a
London Underground line that runs through central London, from
Ealing and
Ruislip in the west to
Epping, Essex in the north-east. Coloured red on the
tube map, the line serves 49 stations, 20 of which are below ground, in . It is the longest tube line. It is also one of only two lines on the
London Underground network to cross the Greater London boundary, the other being the
Metropolitan. One of London's deep-level tube railways, the trains are smaller than those on British main lines.