The Grimsby & Immingham Electric Railway (G&IER) was an electric light railway, primarily for passenger traffic, linking Great Grimsby with the Port of Immingham in Lincolnshire, England. The line was built by the Great Central Railway (GCR), was absorbed by the London & North Eastern Railway (LNER) in 1923, and became part of the Eastern Region of British Railways. It ran mainly on reserved track.
The origin of the line lay in the decision of the Great Central Railway (GCR) to build a vast new docks complex on the marshlands of the south bank of the Humber near the small settlement of Immingham. The GCR reached agreement for the purchase of the land required and presented two Bills in Parliament of which the second was enacted as the Humber Commercial Railway and Dock Act 1904. A number of railways was authorised in connection with the construction and operation of the dock estate, comprising a new main-line railway approaching from Ulceby in the south (the Humber Commercial Railway); a branch from Goxhill in the west, facilitating services to and from New Holland and the Humber ferries (the Barton and Immingham Light Railway); and a direct link towards Grimsby (the Grimsby District Light Railway, GDLR, for which light railway powers were granted on 15 January 1906). Dock operation was labour-intensive and the GCR recognised that it would need to operate a passenger service to bring in dockers from neighbouring towns, principally the fishing port of Great Grimsby about seven miles east. The company also built a large locomotive depot at Immingham, which required workers’ transport. These enactments and considerations were the starting point of the G&IER.
To facilitate construction of the docks the GDLR was initially built from the Grimsby direction as a contractors’ railway and the GCR ran a steam-hauled workmen’s service on this from 3 January 1910. The GCR had two reasons for proposing an electric tramway in addition to this light railway. (Legally the G&IER would form part of the GDLR, although there was no physical connection between them). They had developed a major power generating plant at the Docks, which used electricity extensively for crane and lock operation. This could economically supply the tramway, and did so until 1957. Secondly they envisaged on-street operation in Grimsby itself, extending the area served and facilitating direct connexion with the existing Grimsby and Cleethorpes tramways. The GCR’s 1906 light railway order included a 1½ mile street tramway between Corporation Bridge and Cleveland Bridge in Grimsby, and a private right-of way alongside the existing GDLR between Cleveland Bridge and Immingham Dock.
The electric line opened from Grimsby as far as Immingham Town on the eastern fringe of the dock estate on Wednesday 15 May 1912. It was extended about a mile into the estate on 17 November 1913, terminating at the landward end of the Eastern Jetty, a short walk from the Immingham Dock station of the Barton and Immingham Light Railway. For reasons not fully understood the 1913 extension joined the existing line at Immingham Town by a trailing junction, necessitating a reversal on all through journeys. A short spur was built in 1914 from Immingham Town terminus to Queens Road nearer Immingham Village, but this was never opened to normal traffic, possibly because of the onset of the First World War. The G&IER from Corporation Bridge to Immingham Town was single track with passing loops of a standard length of 110 yards (100 m). The 1913 extension from Immingham Town to Immingham Dock was double track alongside the road, except where it shared the road as it crossed "Tramcar Bridge" east of Immingham Town. There were originally eight intermediate loops on the cross-country Pyewipe – Immingham Town section, numbered in sequence from Pyewipe, although most stops also had names. Four of the loops were removed in 1917, the track being used for war purposes. There were three or possibly four loops on the street section in Grimsby.
There were small waiting rooms and offices at Corporation Bridge and Immingham Dock termini. A temporary structure was erected at Cleveland Bridge after the line was cut back in 1956.