THE SIGNAL BOX

BRANCH LINES

 

THE WEST SOMERSET RAILWAY

A Description of the Signalling
by Kevin Weston

Crowcombe Heathfield

After Minehead was commissioned, the railway was now capable of operating one train every hour to Williton, however, the long block section to Bishops Lydeard restricted the service on the south end of the line to a train every two hours. A normal daily timetable requires only two trains, operating a total of four services each way. The timetable was arranged so that all trains met at Williton. Galas were a problem; very few extra trains could run to Bishops Lydeard and most would only run between Minehead and Williton. To increase line capacity, an extra block post was required. Two crossing loops had existed on this section and in 1992 it was decided to reinstate the loop at Crowcombe Heathfield station.

Diagram of layout at Crowcombe

Crowcombe is at the summit of a climb from both Williton and Bishops Lydeard and in places, the gradient can be 1 in 86. This had always slowed trains and to reinstate the block post would double line capacity on this section. The opening date of the original signal box is uncertain, although it is likely that it was in connection with the conversion of the line to standard gauge in 1882. It contained a 16-lever Stud locking frame up to closure in 1967. This would not have been the original frame if the opening date were correct, as it predates Stud frames by ten years. There is also one source that gives the frame date as new in 1928, The last Stud frame was made in 1908, and so either the date in incorrect or the frame was constructed of reconditioned parts. After closure, the building was completely demolished. To reinstate the crossing loop and signal box required a “new” structure. It was decided to use the original foundations on the down platform. The top portion came from Ebbw Vale Sidings South signal box in south Wales, and is located on a new brick locking room. The lever frame is now in it’s third location. It was first used at Marsh Junction in Bristol and was moved to Frome North in 1970. In 1984, Frome North closed and the frame was purchased by the WSR. The frame has tappet locking for 34 levers but only 29 are required for the new layout at Crowcombe. Some of the signals have been designed in the style of the originals, which had square section posts and wooden arms. The signal at the Williton end of the down platform is a good example; two others are at the south end. The railway has cheated with the “wooden” posts; good quality timber was too expensive, therefore to reduce costs, concrete was used. The new layout allows the signal box to “switch out” when not required. Three train staffs are provided, two for the short sections either side of Crowcombe and one for the section when the box is switched out. All three are interlocked so that only the two “short” staffs or the single “long” staff can be in use at any time. The staffs are also interlocked with the lever frame so that the signal aspects shown to the driver corresponds to the train staff in use.