Introduction

This page provides an outline history of the various methods of Block Working used on the former Somerset and Dorset Joint Railway (S&DJR). Other pages in RailWest provide more detailed information about the different methods and types of block equipment used for working single-line and double-line sections, as well as details about the various examples of S&DJR "shunting staffs". There is also a page listing all S&DJR single-line sections, with details of the various types of block equipment used and their configurations.

These pages concentrate on providing a general overview of the subject of S&DJR Block Working, with a basic chronology of the introduction of the different types of equipment. It is not intended to describe the finer details of the actual Block Regulations or the specific methods of operation of the various types of instruments. (General information about railway signalling can be found at The Signal Box website.) Signalling information for the early years of the S&DJR is still virtually non-existent and so the starting point for these notes is the year 1874, which marks the opening of the 'Bath Extension' from Evercreech Junction to Bath and the expansion of the S&DJR to almost its fullest extent.

Block Telegraph & Crossing Orders

In 1874 the S&DJR was single-line virtually throughout and the railway was worked purely by 'block telegraph' without any form of train-staff. A system of 'crossing orders' was in use, controlled by a 'crossing agent' located in the S&DJR offices at Glastonbury (subsequently moved to Bath), but this system existed mainly to regulate the movements of trains (eg those crossing out-of-course) and was not part of the actual block system.

Contemporary S&DJR Block Regulations show that the method of use of the block telegraph instruments was akin to the single-needle 'speaking telegraph' and did not involve the use of block bells. In 1885 it was agreed to implement "the new Railway Clearing House code of block signalling" with effect from 1-Mar-1886 and it is clear from the subsequent revision of the Regulations that, although bell codes had been introduced, the needle of the block instrument was used still to convey 'dial signals' as well.

The block instruments were located usually in the station buildings and operated by a telegraph clerk, who acted under the instruction of the Station Agent (the S&DJR term for Station Master), as did the signalman himself. It is believed that the instruments were maintained by JB Saunders & Co of Cardiff, who listed the S&DJR as one of the railway companies with whom they had contracts, but little specific information is available. Contemporary records suggest that the block instrument was similar to the 'speaking telegraph', with a handle to work the commutator and a single needle indicator worked from either end - this meant that the indicator merely indicated the presence (or otherwise) of a train in the section, and it was necessary to see if the handle was in the normal position (or not) in order to know if the train was going away or approaching.

Train Staff & Ticket

The 1876 disaster at Foxcote (near Radstock) made horribly obvious the danger of lax working of single-lines, but surprisingly the subsequent Accident Report by the Board of Trade contained no strong recommendations for changes in the method of working the single-line sections. The S&DJR continued to be worked mainly by block-telegraph for a further ten years, but there began to be a move towards better methods of control. The first change was the introduction of 'Train Staff and Ticket' (TS&T) working, which is known to have been in use on a couple of sections by 1886. The use of a physical train staff in addition to the block instruments, rather than relying on instruments alone, certainly provided a more secure system of working. Although more sections were converted to TS&T working during 1886 this did not have a great impact on the S&DJR in the long term, because it was soon overtaken by a further change to the Electric Train Tablet system.

Electric Train Tablet

The most significant change for block working on the S&DJR was the introduction of the Electric Train Tablet (ETT) system in 1885-86. This method of working was introduced initially only on the main line from Bath to Wimborne and Broadstone, but in due course it was extended to cover almost all of the single-line sections and superseded almost all the TS&T working. ETT working became a feature of the S&DJR that existed right up until the closure of the railway in 1966, although during the British Railways era some ETT sections were equipped with the alternative Electric Key Token system. More detailed information about the various methods and changes of single-line equipment on the S&DJR is contained in the specific RailWest pages on S&DJR single-line block working and the list of S&DJR single-line sections.

Double Line Control

By the mid-1880s the S&DJR had embarked on a programme on doubling many of its single-line sections, eventually having continuous double-track all the way from Midford to Templecombe, with a further section from Blandford to Corfe Mullen Junction. It appears that, as various sections of the S&DJR were doubled, the existing equipment and regulations for the 'block telegraph' method of single-line working were applied to double-line use with very little alteration.

The S&DJR Block Regulations introduced in 1886 were still in use in 1889, but thereafter unfortunately there is a gap in available material until 1905. By that time the bell codes had changed to more modern versions and the 'dial signals' appear no longer to form an integral part of block working, although they were still used for some purposes - even as late as 1914 the WTT Appendix contained the following Regulation:

More specific information about the various types of block instruments used on the S&DJR is contained in the separate RailWest page on S&DJR double-line block working.

These notes, and the other associated RailWest pages, deal with S&DJR Block Working only until the closure of the complete S&DJR system to passenger traffic in 1966. Some sections of the line remained opened for freight traffic after that date for a few more years. It is not clear whether these were worked under "One Train Working" regulations, with or without some form of Train Staff, or simply "under signalman's control". Additional information on any aspect or period of S&DJR block working is always welcome and should be sent please to railwest@bigfoot.com .

© Chris Osment 2001