Caledonian Railway


Opened: 1901

Closed: ——

Location code: Sc16/23

Stirling Middle signal boxOpening on 4th August 1901, Stirling Middle was one of three large boxes that controlled the large station and the surrounding junctions. Two of these are still in use today, although the layout has, of course, been drastically reduced over the years.

The box is of the Caledonian Railway's Northern Division 1889 design, described in more detail at Larbert North. Like that box, the locking-room windows have been removed and bricked up.

Mid-way along the building, a bay window has been provided to allow the signalmen to view, flag and communicate with drivers without having to walk to the far end of the lengthy box. This feature actually became superfluous when the lever frame was renewed in the 1950's and placed against the rear wall of the box.

Inside Stirling Middle boxA general view inside the box shows the 96-lever lever frame installed by British Railways. The white lever handles are not painted - they are encapsulated in plastic sleeves to avoid the need to keep the lever handles polished and clean.

Equipment on the long block shelf seems sparse, apart from the block instruments (centre), there are just a few signal repeaters and some illuminated indicators showing the electric point detection. On the right is the signalman's diagram.

Block instruments at stirling MiddleThe block signalling instruments are of British Railways origin. This type were manufactured in-house by the Scottish Region at St. Rollox, and seem to be based on the later instrument of the North eastern Railway. These particular examples are not wholly typical in that the needles themselves seem to be of NER origin, unlike most of those seen elsewhere.

The block bells to the left of each instrument are of LNWR design, often known as "coffin" bells. To the left of the right-hand bell is a LNWR closing switch. Both of these items were adopted as standard by the LMS and were manufactured well into BR days.

A wall clock that undoubtedly predates the rest of the box equipment is located on the back wall behind the instrument shelf.

Signalman's diagram of Stirling Middle (click on image to see lenlarged view)A relatively modern track diagram hangs above the instrument shelf. The rationalised layout still has a large number of track circuits to detect the position of trains. These sections of line are indicated by a pair of red bulbs that illuminate when the track circuit is occupied by a train. Apart from indicating in this way, they also electrically lock specific levers to ensure that signals cannot be cleared, or points moved, which would endanger the train concerned.

To see the diagram in greater detail, please click on the image.

Signals at Stirling MiddleThe very last Caledonian Railway lower quadrant signal survived until 2000 at Stirling Middle. Quite why one arm of a bracket signal should survive amongst a sea of upper quadrants isn't known, but no doubt in later years it became the pride of the S&T department.

The signal concerned was worked by lever 14, and routed trains from the Platform Line towards the Up Loop.

Stirling Middle box survives, but sadly this little friend is no longer with us.

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All photographs copyright © John Hinson unless otherwise stated