THE SIGNAL BOX

BRANCH LINES

 

THE WEST SOMERSET RAILWAY

A Description of the Signalling
by Kevin Weston

Bishops Lydeard

Bishops Lydeard box

Bishops Lydeard is the latest signalling project on the railway. The exact opening date of the signal box is unclear; three sources give the dates of 1902, 1904 and 1906. It is not known what signalling, if any, existed before these dates. The first frame had 25 levers with Stud locking and controlled a layout that consisted of a crossing loop, two sidings located behind the signal box and a third siding to a goods shed opposite, which is now used as a museum. In 1934, when the line from Norton Fitzwarren was doubled, a new 33-lever frame with tappet locking was installed. This was in use until 1970 when the signal box closed and the line was singled. BR removed all equipment from the signal box but left most of the track in place, all points were secured with clips. When the WSR resumed operations, the station was to be the southern terminus of passenger services. With the limited traffic at the time, One Train Working was used with a wooden train staff. To run-round trains, there had to be some alterations to the track at the south end and the Railway Inspectorate required that the points at each end of the platforms were connected to ground frames which were interlocked by the train staff. This system operated for many years, although as the traffic increased, the working of extra trains was restricted. To overcome this, it was decided to operate the station as a block post with Train Staff and Ticket to Williton on busy days. This provided the limited flexibility to allow a second train in the same direction after the first train had cleared the section.

In 1981, plans were drawn up for new signalling scheme. A new frame of 33 levers was installed, using part of the frame recovered from Westbury South, however, for various reasons, not least cost, the scheme was not completed. In 1994/5, the loop was extended to its present length of 275 yards. Once Crowcombe was opened, there was a greater necessity for signalling to make full use of the shorter block sections. In 1997 plans were drawn up for submission to the Railway Inspectorate. The station was still operated as a terminus so we had to allow for trains to arrive and depart from either platform; allowance was also made for through trains from Railtrack. Semaphore signals are used throughout except on the Norton section where there are to be colour light signals. The frame installed in 1981 was re-locked to operate the new layout; the colour light signals are to be operated by switches. Installation will be in two stages, the north end was brought into use between 4th and 11th August 1998 and consisted of one point, four single arm stop signals, a four-arm bracket signal and a new distant signal. The bracket signal has a stop arm and a calling-on arm for entry to each platform. The home signal for trains from Crowcombe is the third on the railway to be worked by a Westinghouse signal motor. A Westinghouse style M3A point machine, the same type as used at Blue Anchor, operates the point. Six track circuits are provided as the approach to the station is out of sight of the signal box. This is the first signal box on the railway where we have used BR specification 50-volt plug-in relays for the main interlocking. The older 12-volt shelf relays are no longer available in large numbers so we have to upgrade to the modern standard.

Signals at Bishops LydeardWe suffered a few set backs early in the scheme, woodworm and dry rot were found in the signal box floor and some of the support timbers. The tiles on the roof where found to be loose and a number of them had to be replaced. This delayed the re-locking of the frame and the installation of the new wiring. We also suffered from a number of thefts. Most of the items taken appeared to be for “collectors”, these included a reconditioned ground signal. The signal did not have a lamp case attached so the thieves returned two days later to Crowcombe and took one from a working signal. We also lost two new signal arms and about £7000 worth of signalling cable in three separate occasions. One of the most unusual items taken was a number of track circuit bonds, these are lengths of galvanised steel wire that go across the rail joints in track circuits. They have no real scrap valve, and certainly no valve to a “collector”, but an unopened 25-kg bundle was taken.

Work on the south end will involve removing the south ground frame and connecting the points to the signal box. Five runs of between 100 yards and 200 yards are required, a total of 900 yards of rodding. The goods shed points are clipped out of use at the moment, but these should be first to be connected the signal box as stage 2a. Two more bracket signals are to be erected; the first was raised on Wednesday 12th April. There is also a centre-balanced wooden signal arm, this is all new as the original arm had rotted and there was rust in the metal frame. Most of the south end signalling has been installed, throughout the summer it will be connected up and tested. Even after testing we must wait for permission from the Railway Inspectorate before it can be brought into use.