THE SIGNAL BOX

PHOTO GALLERY

British Railways (Scottish Region)

THORNTON YARD

Opened: 1956

Closed: 1991

Location code: Sc42/27


Thornton Yard signal boxOver the years Thornton (Fife) possessed nine different boxes - apart from Thornton North, South, East and West there was a Thornton Colliery, Thornton Station, Thornton Central, Thornton Weighs and Thornton Yard. Naming these was the subject of the August 1999 quiz. By 1980, all except the latter had closed, being engulfed by power signalling controlled from Edinburgh. Thornton Yard was retained to allow local control of the yard it supervised and the Kinglassie branch.

The box also happened to be the newest, having opened in 1956 when a new hump yard opened. The box was built, interestingly, to the same design used by the Eastern Region, as illustrated at Sleaford South. Boxes of this type were erected by the Scottish Region between 1955 and 1961, but later boxes, like Stanley Junction, varied considerably.


Inside Thornton Yard boxWhen first opened, all but four levers were in use, but there was never much signalling equipment on the block shelf for the box was always primarily concerned with shunting.

The 35-lever frame is to the design of Stevens & Sons, first introduced in the 1870s, but adopted as standard in Scotland and manufactured (by various contractors) right up to 1970. Visible variations on newer examples include white plastic sleeves on the lever handles and tapering "coffin-lid" ivorine lever plates.


Another view inside Thornton Tard boxAfter 1980, the number of spares increased to fifteen. Trains on the two Down Departure lines were signalled to Edinburgh Signalling Centre by means of the train describer mounted at the right-hand end of the block shelf.

Despite being a fringe cabin to Edinburgh, only one lever has a power-operated function - lever 34 controls a slot on incoming signals to the Arrival Line. Interestingly, the lever is painted red above brown.


Track layout diagram at Thornton YardThe track diagram above the instrument shelf is an essential aid to signalmen - it shows the signals and points (with their corresponding lever number) and the "track circuits", which indicate the presence of trains. Each track circuit is indicated with different colours on the plan, and a red bulb at each end of the section will be illuminated when the line is occupied.

View enlargement of diagram.


Tyers Key Token InstrumentThe line running off to top left on the diagram is the single line Kinglassie branch. This is the Tyers key-token instrument for that section. Each of the large brass keys stacked in the machine will permit a train to enter the single line, but the instrument is so designed that only one key can be withdrawn from either this instrument, or the one at Kinglassie, at any time.


Telephone concentratorWhilst signalling enthusiasts mourn the progressive loss of traditional signalling equipment, a feature often overlooked is the associated telephone gear. Thornton Yard possessed this splendid telephone concentrator, where all telephone lines would connect. Two handsets are provided, and selection of the circuits is made by the array of switches on the front.

Thornton Yard box closed in 1991.



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All photographs copyright © John Hinson unless otherwise stated