The Eastern Counties Railway (ECR) had originally proposed plans to extend what is now the Great Eastern Main Line from Colchester to Harwich, although this was a cause for concern to the town of Ipswich, which was a rival port.^[4]

In 1846 a railway line from Manningtree to Harwich proposed by the Eastern Union Railway (EUR) was approved by the Railway Commissioners. In 1853 an agreement was reached between the companies, with the ECR taking over the working of the EUR from 1 January 1854. The single-line branch opened on 15 August 1854.^[4]

In 1862 the ECR and the EUR merged to form the Great Eastern Railway (GER).^[4]

The track was doubled in 1882 by the GER, and the Manningtree North Curve which allows direct running between Ipswich and Harwich was also added at that time.

In addition to the closed station at Bradfield, there was a halt stop called Priory Halt between Wrabness and Bradfield which serviced the adjacent War Department facility; the halt station closed in 1965.^[5] There was a relatively extensive system of sidings fed from a spur on the "down" (Harwich-bound) side which was controlled by a signal box which was in use from 1918 until 1966.^[6] Use of the halt was confined to Admiralty employees only during various periods.

The War Department also had a munitions dump in Copperas Woods between Wrabness and Parkeston served by a spur which was situated on the north (river) side of the line just west of the point where the original alignment of the track to Dovercourt and Harwich Town had been changed when Parkeston was built. This spur was controlled by a signal box, named Primrose Box, reflecting the profusion of primroses which grew lineside in the area.^[5]

In 1948 following nationalisation the line became part of British Railways Eastern Region.

By the late 1970s the costs of running the dated mechanical signalling systems north of Colchester was recognised and in 1978 a scheme for track rationalisation and re-signalling was duly submitted to the Department of Transport. This was followed by a proposal to electrify the Great Eastern Main Line and branch to Harwich in 1980. Electrification work was undertaken in the early – mid 1980s.^[7]

In 1982 British Railways sectorised their operations and the branch fell under the London & South East (later renamed Network SouthEast in 1986).

On 14 April 1985 the first electric train consisting of two Class 308 electric multiple units (EMU) worked the line although the previous year another member of the class had been dragged from Ipswich to Parkeston and used for crew training. The following day a Class 86 locomotive visited the branch to test various sidings and crossings on the line. The full electric service was introduced on 12 May 1985 with InterCity Class 86s working the Liverpool Street boat trains and EMUs working local services.^[8]

The line was given the marketing name the "Mayflower line" in September 1997, with a ceremony held at Mistley in the presence of local MP Ivan Henderson.^[9]

The line diverges from the Great Eastern Main Line at Manningtree and is double-track for passenger services as far as Harwich International, where connecting ferry services are available to Hook of Holland on Stena Line. Until 2014, Esbjerg was connected by DFDS which is now closed. Beyond Harwich International, the original second track remains in place as a through siding, but only the "up" (Manningtree-bound) line was electrified and that section to the eastern terminus Harwich Town is bidirectional.^[5]

East of Manningtree there is a triangular junction that enables trains operating to the port to reach the branch from both the north and south. The line is electrified at 25 kV AC using overhead wires and has a loading gauge of W10 (excluding W9);^{[clarification needed]} the maximum line speed is 60 mph (97 km/h).^[1]

The shortest platform is the "down" (Harwich-bound) platform at Wrabness, which is 90 yards (82 m) in length.

Stations edit

The following table summarises the line's six stations, their distance measured from London Liverpool Street, and estimated number of passenger entries/exits in 2018–19:

In 2015, a trial of an electric overhead wire/battery train was undertaken on the line. A single Class 379 Electrostar began a passenger service after electric lithium batteries were installed. The train could travel up to 60 miles on energy stored in the batteries; it recharged the batteries via the overhead-wires when on electrified sections of the line, at stations and through brake regeneration.^[10] Network Rail refer to this prototype model and its possible future descendants as Independently Powered Electric Multiple Units (IPEMU).^[11]