The Northern line is one of two commuter rail routes operated by Merseyrail and centred on Merseyside, England, the other being the Wirral line. The cross-city route runs from Hunts Cross in south Liverpool then branches in the north to terminate at Southport, Headbolt Lane and Ormskirk (Lancashire).

Urban and suburban rail plays a key role in public transport in many of the major cities of the United Kingdom. Urban rail refers to the train service between city centres and suburbs or nearby towns that acts as a main mode of transport for travellers on a daily basis. They consist of several railway lines connecting city centre stations of major cities to suburbs and surrounding towns.