THE SIGNAL BOX

BRANCH LINES

 

THE WEST SOMERSET RAILWAY

A Description of the Signalling
by Kevin Weston

History of the line

The original West Somerset Railway Company was incorporated by an Act of Parliament on 17th August 1857 and was authorised to construct a line from a junction with the Bristol and Exeter Railway (B&E) at Norton Fitzwarren to the harbour at Watchet. Construction started at the site of Crowcombe Heathfield station on Thursday 7th April 1859 and the line was opened on Monday 31st March 1862. It was built to the broad gauge of 7ft 01/4in and operated by the B&E from the start. The Minehead railway began work in 1871 to build a line from Watchet to Minehead, a distance of 81/2 miles. From the opening day on Thursday 16th July 1874, the B&E operated the line as a through route from Taunton. The B&E were taken over by the Great Western Railway (GWR) on 1st January 1876 (some sources give the date as 1st August 1876) who converted the branch to standard gauge over the weekend of 28-30th October 1882.

Although the branch was now operated by the GWR, it still remained the property of the two independent companies. The GWR took over the Minehead Railway on 1st July 1897 and the West Somerset Railway on the 1st January 1922. The GWR carried out major engineering works in the 1930's, including the upgrading of the single track to double track double track between Norton Fitzwarren - Bishops Lydeard and Dunster - Minehead. Two new crossing loops were installed at Leigh Bridge and Kentsford.

Nationalisation in 1948 originally saw little change to the branch. In the 1950’s, a number of the wooden post signals were replaced with tubular steel posts. During the 1960’s there were reductions to the signalling; the crossing loops and signal boxes at Crowcombe, Leigh Bridge and Kentsford were removed. The double track section from Dunster was converted to two single-track sections and, with the closure of Minehead signal box, there was no connection between them at the terminus. There were further economies in 1970 to try and make the branch profitable; the double track section to Bishops Lydeard was removed, together with the closure of Bishops Lydeard and Norton Fitzwarren signal boxes. This section was now worked as one single line from Silk Mill Crossing signal box to Williton. The three remaining signal boxes had level crossings, which is why they were not closed. Even with these reductions, the branch still required the three signal boxes to be manned for two shifts each, and four isolated level crossings, each manned by a crossing keeper. Including the train crew of a driver and guard, it required 9 people to operate a train and it was no surprise that passenger traffic was withdrawn on 4th January 1971.

Reopening in private ownership

The present West Somerset Railway Company reopened the line in stages, starting with Minehead to Blue Anchor on 28th March 1976 and to Williton by the end of the year. Full services to Bishops Lydeard commenced in 1979.

The WSR operates from the Railtrack boundary at Norton Fitzwarren (milepost 1651/4) and is single line throughout, a total of 221/2 miles. Regular passenger trains operate between Minehead and Bishops Lydeard, 3 miles from Norton. On gala days, special trains run over the Norton section; with no run-round facilities at the Railtrack boundary, the train operates with a locomotive at each end. There are intermediate crossing loops at Bishops Lydeard, Crowcombe Heathfield, Williton and Blue Anchor. At each crossing loop is a signal box, controlling entry to the block sections. Crowcombe can “switch out” when not required for crossing trains, the block section then becomes Williton to Bishops Lydeard.

The WSR uses three systems for control of the single line sections. One Train Working (OTW), with a wooden train staff, is used on the Norton section; when WSR trains traverse this section, they only travel as far as the Railtrack boundary and then return. Through trains from Railtrack require the staff to be conveyed by road to Taunton station before the train can enter the section. The three sections between Bishops Lydeard and Blue Anchor use Train Staff and Ticket (TST). When Crowcombe is switched out, a long section staff is used between Williton and Bishops Lydeard. The Minehead - Blue Anchor section uses Electric Key Token (EKT). Communication between signal boxes for block working is by British Telecomm telephone, except the Minehead - Blue Anchor section, which is by block bell using a system of bell codes.

Details of the individial locations are to be found on separate pages of this article:

Williton Blue Anchor Minehead Crowcombe Heathfield Bishops Lydeard Norton Fitzwarren

Signalling equipment

The WSR has two types of frames; both types were designed and manufactured by the GWR in the signal works at Reading. The 5-bar tappet locking frames date from the 1930’s. The GWR did not use tappet locking until 1906 when it produced a 3-bar tappet frame; its earlier frames had “twist” locking, where all the connections were rotated to engage the locking. Despite this complicated arrangement, several twist frames are still in use, although the last two on Railtrack have been converted to tappet locking. The GWR developed the Stud frame in 1892 as a replacement to the twist frames, when most other railways were changing to tappet locking. It operates in a similar manner to tappet locking except that the blades are curved; the radius of the blade is centred on the pivot point of the lever. The locking bars are known as “slings” and the wedges are round and known as “studs”. There is no locking tray, all the slings are arranged above and below the blade on a piece of 6 by 23/4 channel iron. This limited the amount of locking that could be accommodated and 37 levers was found to be the practical maximum. Any alteration required the entire locking to be disconnected, particularly if it was the bottom sling on a large frame. It was no surprise, therefore, that the GWR soon changed to tappet locking to replace the twist frames.

The power supply used in the signal box areas is standard 110-volt ac, 50Hz, which is obtained from the domestic supply of 230-volts ac. The isolated level crossings are fed direct from the domestic 230-volts to overcome voltage drop on the long feed cables. Locally, the crossing circuits use 24-volts dc. All equipment, such as relays, lever locks and indicators operate at various dc voltages and is mostly ex BR. Float-charged standby lead-acid batteries are provided at all locations to cover any mains power failure. We use two types of relays for interlocking. The older “shelf” type, are, as the name implies, designed to sit on a shelf. They were originally worked from low voltage dry cells but with the increase of the national grid power supply, rectified 12-volts is now used. We also use BR specification “plug-in” relays, which are available for 24 and 50-volt operation. They fit into pre-drilled bases mounted in specially designed relay racks. Track circuits are fed at 2-volts dc with relays designed to pick at a nominal 0.5-volts. Track circuit relays are available in both “shelf” and “plug-in” specification. Indication relays are manufactured to a lower specification, as they are not vital in the safe interlocking. Various indicators are provided in the signal boxes to repeat the condition of signals, points and power supply.

When the signalling is finished at Bishops Lydeard towards the end of 2000, this will be the last signal box to be reopened. Over the next few years there will be several projects, provision of cable along the railway to extend the Electric Key Token working and refurbishment of the original equipment at Blue Anchor, Williton and the level crossings. Maintenance, of course, will always be an ongoing task.

As a Heritage railway, we try to use signalling that reflects the history of the line but it should be remembered that all the equipment has been installed with a practical purpose in mind. We are an operating railway and are subject to the safety requirements of the Railway Inspectorate in the same way as the national track operator, Railtrack.

All the signal boxes are accessible from the public areas of the stations, except Minehead. This can only be reached from a public footpath that follows the railway from the station. Visitors are welcome, but please remember, this is an operating railway and when there are trains about, the signalman does have his job to do. Further information about the railway can be obtained from the addresses below.

West Somerset Railway, The Railway Station, Minehead, Somerset, TA24 5BG, England.

Telephone: 01643 704996.

E-mail: info@West-Somerset-Railway.co.uk

Williton Blue Anchor Minehead Crowcombe Heathfield Bishops Lydeard Norton Fitzwarren

Kevin is keen to obtain any additional information on the signalling history of the line, especial of that at Crowcombe. Please contact Kevin at the address below.

Comments about this article should be addressed to Kevin Weston