Great Central Railway

Opened: 1912

Closed: ——

Location code: E48/13

Another of the Great Central's power schemes was introduced in the Immingham docks area in 1911. Whereas the earliest Great Central installations used air pressure for point and signal operation (such as at Hyde Junction), this and later schemes used all electric operation. It may have been lack of faith in modern electrical technology that resulted in this exercise being carried out in a freight-only area.

Reception Sidings box is quite a large version of the Great Central's final box design, a type which continued to be erected right through to 1930, well into LNER days. A determination to protect it, and the adjoining lamp room, from bomb damage during world war two resulted in ugly brick enclosures. Notice how the adjoining hut is built to the same architectural style.

The box was originally built for the Humber Commercial Railway & Dock Company and was subsequently leased to the GCR. There were originally six boxes in the area but now just three remain.

The box remains in use, but is not Railtrack property. It actually belongs to the Assiciated British Ports, which explains the blue colour scheme, although it is manned and maintained by Railtrack under contract.

Inside we find a similar frame to that seen at Hyde Junction but rather larger - being of some 91 slides spaced at 3" intervals. The original layout must have been quite extensive, although many slides are now redundant and out of use. Some have been removed permanently.

The instrument shelf carries a sparse range of equipment, but a smart Tyer & Co. permissive block instrument, and its associated bell, stand in the foreground.

Although the layout has been considerably rationalised, some expansion has also taken placeand two small modern panels can be seen at the far end. The panel on the block shelf was installed in 1970 to control the entrance to the export coal terminal, which was rendered redundant by the miners’ strike whilst at the same time assuming control of the branch to Immingham West Junction from the slide frame.

One of the two panels is a fully-fledged "NX" panel controlling the triangle at Humber Road Junction. This was commissioned in 1967 when the two large oil refineries opened.

The term "NX" refers to "Entrance-Exit" working - each route requires a button at the entrance and a button at the exit to be pressed to initiate the route. The route will then set all the required points and clear the signal.

The row of switches at the lower right allow for controlled operation of points during special working, and the stack of red magnetic blocks at the bottom are the equivalent of lever reminder collars in miniature.

To signal a through train on the main lines in involves the frame, the switch panel and the NX panel.

Returning to the slide frame, notice the cast brass numbers above the slide handles, and the horizontal plates below that describe the function of each slide. Many spaces exist where redundant slides have been removed.

Access to the frame's mechanism is through the glass lids with handles.

The equipment from that appears to belong to a horror movie controls the power supplies for the points, signals and detection and is called the Cabin Switch Board on the original circuit diagram. Nicknamed “The Clock”, it contains amongst other things a trip switch, which comes into operation when any stray and earth currents are present. When it trips, the 110v D.C. point and signal supply is fed through two resistance lamps located at the top of the cabinet. This prevents any operation but allows enough current to flow in order to maintain any signals in the “off” position. The door is open – presumably that trip switch was playing up!