From 1896 there was a junction to the Liverpool Overhead Railway between North Mersey Branch Junction and Gladstone Dock. Aintree Racecourse station opened around 1890 as the only station on the line and saw its last service on 25 March 1961. It only operated on race days at Aintree Racecourse. Gladstone Dock station opened on 7 September 1914, when the section of track from North Mersey Branch Junction was electrified, and closed on 7 July 1924. Two more stations on the line opened on 1 June 1906 with the electrification of the line; these closed on 2 April 1951. Freight trains ran from Edge Hill and further in the country along the North Mersey Branch to Aintree Container Base, situated at the site of Ford Railway Station. Some ran further east to Fazakereley Yard via Sefton Jc. Grand National Express trains ran from London and other locations in the country, direct to Aintree Station via the North Mersey Branch and Bootle Branch Line which has a direct connection to the WCML. In 1988 the decision was made by BR to cancel the Grand National Express for good due to attacks from vandals at two locations along the line. Missiles, bricks and other objects would be thrown at the train when coming down to the old site of Spellow Station in Walton, therefore giving this cutting the title “Bomb Alley” and then further North in Litherland on the old site of the North Mersey Junction at the end of crossover above the Merseyrail Northern Line. BR made the decision to stop after too many of their trains and coaches were arriving into Aintree with significant damage. In 1986 the line to Aintree Container Base was cut leaving no further need for container trains along the line. In 1987 the short spur to Fazakerley sidings was closed and the Metal Box service had finished by 1991 leaving no regular goods services on the North Mersey Branch.
Today
The section of the line between Sefton Junction and North Mersey Branch Junction is no longer maintained to basic Network Rail operational standards and as of December 2017 is completely overgrown in places. Occasional diesel-powered engineering/maintenance trains used to use the branch to access the Southport line, saving the need to reverse at Sandhills. For trains to access the branch, a key must first be obtained in advance from the MerseyrailIECC signalling centre which unlocks the gate allowing access to/from the branch line at Aintree. The line is largely single track and is not electrified.
Future
Plans to open this section as part of Merseyrail's Northern Line have been put forward in Sefton's transport plan, with the first details to emerge about its possible reopening being published by the media on 28 February 2008. The Crosby Herald newspaper reported that the line could be reopened in conjunction with a proposed new stadium for Liverpool F.C., to provide additional transport links via the town of Litherland, likely to cost millions. This was again mentioned in Merseytravel's 30-year plan of 2014. In January 2019, Campaign for Better Transport released a report identifying the line which was listed as Priority 2 for reopening. Priority 2 is for those lines which require further development or a change in circumstances.