GWR Route: Banbury to Wolverhampton

Small Heath and Sparkbrook Station: gwrsh2285

One of the Great Western Railway ‘Train Describer’ instruments thought to be from Small Heath South Signal Box. On busy or complex routes it was useful for a signalman to know the destination of each approaching train and this lead to the development of the train describer instrument (also called route indicators). This train describer instrument was manufactured by Tyer & Company, who had patented the design in December 1879 (Patent No 2575).

The top dial received indications from a similar instrument in the adjacent Tyseley North Signal Box about the destination of the train approaching on the down relief line, while the lower instrument was used by the signalman at Small Heath South Signal Box to transmit indications to the signalman at Tyseley North Signal Box about the destination of the train leaving his section on the up relief line

The instrument worked by the placing of a metal peg into the appropriate hole and then pulling out the plunger on the right hand side. This plunger was spring loaded which provided the mechanical power to drive a small armature within the case. The armature rotated clockwise passing a series of contacts until it was stopped by the pin. As it passed each contact an electrical pulse was transmitted to the remote end where each pulse incremented the pointer on the dial of the receiving instrument.

This particular instrument is displayed in the Winchcombe Railway Museum collection.

The Great Western Railway magazine of November 1910 carried the following article: Train Describers: Tyseley and Handsworth

Consequent upon the extensive alterations now in progress in the vicinity of Birmingham and the reconstruction of the Birmingham Snow Hill Station, it has been determined to equip the Up and Down main and Up and Down relief lines between Tyseley Junction and Handsworth Junction with train describers. The Up and Down avoiding lines between Birmingham North and South Boxes will, in addition to the Up and Down main and Up and Down platform lines, be similarly equipped. The work will involve the provision of sixty sets of apparatus, each consisting of a transmitter and receiver, the number of indications varying from six to ten, due regard being paid to spares in view of future development. The instruments will be constructed on what is known as the ‘step by step’ principle, a single-line wire sufficing for each set of apparatus. The object of the train describer is of course, to give instant information of the destination of approaching trains to signalmen to enable them to promptly dispose of the trains in their proper order. Doubtless the introduction of the system will be much appreciated by those responsible for the conduct of the traffic on the section in question.

Robert Ferris

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