THE SIGNAL BOX
THE SPEAKING TELEGRAPH
Cooke & Wheatstone replaced this in 1843 with a new type, using just two needles (and therefore three electrical wires). The letters of the alphabet were identified by counting the number of deflections of the needle, rather than the single deflection method of the five-needle instruments. This was the equipment that achieved fame by warning of murderer seen leaving Slough in 1845, leading to his arrest at Paddington. It is worth noting, although not significant to this tale, that the two needles were marked for Up Trains and Down Trains, suggesting their later use for signalling purposes.
Letters of the alphabet were identified by multiple strokes of the needle, but it is not clear as to whether the two circuits were used independently for "Down" and "Up" messages, or whether the separate needles were used for sending and receiving messages.
The alphabet was achieved as follows:
Telegraph became more commonly used from 1845 onwards. The need for separate Up and Down needles was, of course, not significant when the instruments were being used solely to transmit messages, and single-needle instruments spread from the early 1850s for general communication. Most of these were built by Tyer & Co.
Interestingly, as the proper block signalling system developed, many redundant telegraph instruments were rebuilt into block instruments and quite a number of these conversions are still in use today.
The continuing use of the "single-needle speaking telegraph" is not well documented. It is known that they were the only means of conversing between signal boxes on the former GN High Barnet branch right up to the resignalling by London Transport in 1939. It is also said that such instruments existed in station offices on the former LNW Windermere branch until the 1950s for communications about wagon loading and passenger matters. But the most significant survivors were to be found on the erstwhile Great Northern main line. Here, a complex network of circuits supplemented the telephone network, being used in the main to announce late running trains for regulating purposes.
For a moment, visualise yourself as a signalman in a box in the days when the only means of conversation is the telegraph. No telephones. Supposing you need to discuss with your colleague in the next box some minor block irregularity that has occurred, or maybe to discuss the racing results. The telegraph would be far too public - everyone on the circuit could read your conversation, including the Station Master who would certainly not approve. It could not have taken long for signalmen to realise they could use the block instruments as telegraph for private conversations.
As early as 1889, warnings were issued against doing this, and the instruction was still to be found in the British Railways Regulations for Train Signalling as late as 1972:
Use of Block Indicators and Bells. These must be used exclusively for the purposes shown herein and must not under any circumstances be used for conversing.
As far back as 1873, a Captain Mallock was commissioned to review
block working for the Indian government and stated to the Society of Telegraph
Engineers that "A needle instrument of any sort permits of talking, and is
dangerous". He preferred one wire two position instruments (such as Tyers) for
this reason. In the discussion that followed, Mr. Chubb (a director of the
North London Railway, and previously manager of that line) agreed. They used
Tyers* instruments and "the men could not talk with it. The men would talk if
it was possible, and he found the best way was to let them have a speaking
instrument in addition to Tyers." This was a remarkably enlightened attitude
for an early Victorian manager.
* - The North London actually used Pryce & Ferreira instruments, manufactured under licence by Tyer & Co.
An interesting early single-needle instrument thought to be a Bain "I & V" instrument used through Shildon Tunnel on the Stockton & Darlington Rauilway. Seen here laid on its back, it had the needle enclosed in a large glass-fronted wooden case.
It is curious that such a large case was supplied to contain such a small mechanism.
On the single-needle instruments, the Cooke & Wheatstone and other complex codes were abandoned and instead messages were sent morse code. The needles no longer required to be observed visually to be read - metal sounders were provided so that deflections could be identified by ear as a "ting" and a "tong". These sounders were, in fact, often enhanced by signalmen by the placing of a tobacco tin tightly on the sounders, producing a sharp "click" and "clack".
Morse code was not used in the traditional sense, in that there was no distinction between the length of a dot or a dash. Each was of equal duration, a dot being represented by a right-hand deflection of the needle (a low note on the sounder) and a dash by a left-hand deflection, with the higher note. Thus each letter would be identified by a combination of notes, staff identifying them more by the tune than by reading morse code.
Incidentally, figures were spelt out as words, rather than using the traditional morse code numbers. This was probably to ensure clear identification in messages that contained so many figures. Again, staff would read each number by its tune rather than letter by letter.
Messages would be acknowledged with M (understood) or E (not understood).
Each location, be it a signal box or telegraph office would have a two-letter identifying code - usually one that made a distinctive tune for easy identification.
Here are some sample codes
It should also be mentioned that some busy locations had local circuits between boxes for train routing purposes. In these instances, the instrument was mounted on the block shelf adjacent to the relevant block instrument, and the two letter identifying code of the train's destination would be sent after signalling the train on the block bell. The normal circuits would generally be mounted at waist level near to the train register desk.
A few boxes had an "exchange", working in a similar manner to a telephone concentrator. A bank of circuits would be provided, each with a switch that could link it to the one instrument provided that had sending capabilities. Circuits could be connected through by switching two circuits to the sending instrument. Owing to the length of a through connection, signals could sometimes be weak.
Operators in the telegraph offices generally had a more sophisticated instrument, with a piano key arrangement for sending messages. Some were in traditional style, as shown here, whilst others were rather more modern. Little information exists about the introduction of the latter, but the fact they were made from matt black-painted plywood suggests they were not that old!
As has been said, these single-needle instruments survived in intensive use right into the early 1970s. They were popular with signalmen as there was no need to pick a phone up to take a message, and indeed it was possible to hear messages intended for others and get a picture of how trains were running. With this information, signalmen were able to regulate traffic accurately without any need for Control intervention.
My own first job on leaving school in 1971 was as "Telegraph Lad" at Kings Cross. Elsewhere, the job would have called Booking Boy, or Box Lad, for that was really what the job was. However part of the job required the receiving of messages from Crescent Junction (Peterborough), Hitchin South and Hatfield No.1 about the running of Up expresses. We were required to calculate from their passing times how late they were running, and this was marked on a card which was transmitted to key points on the station (such as the Train Announcer's Office and the Arrivals Indicator) by closed-circuit television. An amazing contrast between 1830s telegraph to the latest 1970s technology!
To learn the telegraph, I was sent to the Signalling School at Ilford, where I sat through a full signalman's course in order to benefit from the small amount of it devoted to the telegraph. I suspect I must have been among the last to be trained to use it, and I could still manage to send messages today, although I would be a bit rusty on the receiving.
Some of the other messages we received were on more general traffic matters. For instance, every Sunday afternoon, a message would come from Crescent Junction:
COW 2B18 1 BG PARCELS POST
This curious sounding message, when read in conjunction with the Telegraph and Telegrams Code book, tells that there is an additional brake van attached to the rear of train 2B18 loaded with parcels post traffic.
Whilst the presence of telegraph instruments in traditional mechanical signal boxes didn't seem out of place, the sight of one in the 1950s power box at Potters Bar certainly did. Nevertheless, without abandoning the entire system, it was necessary to provide one there.
The first sign of abandonment of the system was when the old Kings Cross miniature lever power box closed in 1971, and the layout transferred to the control of a small temporary panel in the corner of the new power box that was being prepared to control a large part of the ECML. Dignity, perhaps, over-ruled common sense, and three brand new telephone circuits were provided to allow, for the first time, verbal communication with Crescent Junction, Hitchin South and Hatfield No.1. The telegraph instruments continued in use elsewhere on the line, in most cases right up to the closure of the boxes. The last circuit in use was Newark South-Doncaster telegraph Office, taken out of use on 18th october 1976.
unofficial code for "Goodnight!"
Additional notes by Andy Emmerson, John Liffen, Mick Nicholson, Chris Randall and Andrew Waugh.
Comments about this article should be addressed
to John Hinson