[8][10] The Wirral line has carried its present name since the opening of the Merseyrail network by Queen Elizabeth II on 25 October 1978,[11] during the British Rail period.

The Wirral line is fully electrified with a DC third rail,[8] and has existed in its current form since May 1994 with the start of electric services to Ellesmere Port.

[12][13] A total of 34 stations are served, with connections available to mainline services at Liverpool Lime Street, Bidston, Ellesmere Port and Chester.

The route between the two settlements was surveyed by George Stephenson in 1830,[18] but the railway company itself was not incorporated until 12 July 1837,[19] after a previous bill had been rejected a few months earlier.

By October 1839, over 900 navvies and 40 horses were employed on the southern 5 miles 37 chains (8.8 km) of the route, which included the construction of Mollington Viaduct over the Shropshire Union Canal at Moston, now Grade II listed.

[33] A 5 miles 22 chains (8.5 km) single track line was constructed between Hoylake and Birkenhead Dock (adjacent to Wallasey Bridge Road),[34] and the railway opened to passengers on 2 July 1866.

[32] The railway had ambitious plans that included the construction of a bridge across the Dee Estuary to join the LNWR North Wales Coast Line at Mostyn,[35] but due to financial difficulties the company went into receivership on 13 February 1869.

[32] The North Wales and Liverpool Railway opened for passengers on 18 May 1896, but powers to extend the service from Bidston to the more appealing destination of Seacombe were not granted until 1898.

The bill received the support of the chairman of the Mersey Docks and Harbour Board and of John Laird, the Member of Parliament for Birkenhead at the time, although ultimately it was unsuccessful due to strong opposition from the LNWR.

[44] A second tunnel proposal was made in 1865 by Sir Charles Fox, who planned to build a single track pneumatic railway under the Mersey between the two settlements.

[49] It was determined that there was an almost uninterrupted stratum of red sandstone beneath the river[50] and as a result construction began in August 1881,[51] before the pilot bore had been completed.

[53] Steam-driven ventilating fans were installed at James Street, Shore Road and midway between Hamilton Square and Birkenhead Central.

[61] By the end of April 1903, and at a cost of £300,000, the electrification work was complete,[62] making the railway Britain's first steam-operated line to be converted to electric traction.

From 1904, driving controls were also fitted to selected trailer vehicles which enabled trains to be divided into shorter units during quieter times, yet still be drivable from both ends.

[68] Additional vehicles were added to the fleet in 1925 and 1925, constructed by Cravens of Sheffield, and in 1936, built by the Gloucester Railway Carriage and Wagon Company.

[34] To allow through services to run to Liverpool, all trains had to be able to operate with both systems, and automatic changeover devices were installed between each set of rails at Birkenhead Park.

[73] The explosion of a parachute mine just west of Birkenhead Park station demolished the carriage shed that was located there; damaged vehicles were sent to Wolverton works and extensively rebuilt.

At first, services continued as before, with trains from New Brighton and West Kirby to Liverpool Central, and services on the former Birkenhead Joint Railway from Birkenhead Woodside to destinations such as London Paddington, Chester General, North Wales, West Kirby (via Hooton), Wolverhampton Low Level, Birmingham Snow Hill and Shrewsbury General.

Liverpool City Council took a different view, and proposed the retention of the suburban services and their integration into a regional rapid-transit network.

[82] The one track Loop Tunnel was designed to allow trains to run in a clockwise direction beneath Liverpool's city centre.

The Loop is a single-track tunnel, 2 miles (3.2 km) in length, 4.7 metres (15 ft) in diameter, and was driven during 1972 and 1973 through mainly sandstone rock.

To bore the tunnel, three new DOSCO electro-hydraulic excavating machines were used, giving a maximum work rate of 57 metres (187 ft) per week.

The first phase of the Merseyrail development was formally opened by Queen Elizabeth II on 25 October 1978, when she visited Liverpool Central station and rode to Kirkby on the Northern line.

[85] Due to a stock shortage in the Southern Region, the new four-car trains were first introduced to operate inner-suburban services from London Waterloo.

[85] In the early 1980s, plans were made to extend the Wirral line from Rock Ferry to Hooton along the former Birkenhead Joint Railway route.

[88] Bromborough Rake station opened along the line to coincide with the introduction of electric services, and diesel multiple units provided onwards connections at Hooton to Helsby and Chester.

[17] In conjunction with this, on 20 July 2003, the franchise was awarded to Serco-NedRailways (now Serco-Abellio), a 50-50 joint business venture between Serco and Abellio, a subsidiary of Dutch national train operator Nederlandse Spoorwegen.

As part of the agreement with Angel Trains, the fleet would receive a refresh package including external re-livery, internal enhancements and engineering work.

[107] Various proposals over the years have suggested the electrification of part or all of this route and incorporating it into the Wirral line, as well as also electrifying beyond Ellesmere Port through to Helsby.

[131] The West Kirby branch of the line has several level crossings, and accidents at these, involving pedestrian fatalities, have taken place in July 2007,[132][133] January 2008,[134][135] and November 2009.