The railway 'speaking' telegraph

When we added an early example of a GWR single needle 'speaking' telegraph to our collection we decided to do a little bit of research into its early development and use. This page can only serve as the briefest of introductions to a fascinating subject. But why are such instruments called 'speaking' telegraphs? The name derives from the fact that, rather than simply displaying fixed codes, they can be used to convey any desired message between operators who could therefore 'speak' to each other.

With all the systems described below there would be two identical instruments, one at each end of the wires. For speed and clarity the railway companies went on to devise a set of code words to replace complicated or regularly used phrases. Some codes were proper words whilst others bore little resemblance to their message. Many different codes were used to describe particular wagon or carriage types for example. Such words remained in use for many years, but codes might fall from use or be added to, reflecting changing requirements. Individual railway companies had their own code systems but there were also standard codes which were understood and used across the industry.

Development of the telegraph

Five needle telegraph

In 1837 William Cooke and Charles Wheatstone developed and patented a telegraph instrument. It exploited the relatively new discoveries of Danish scientist Hans Christian Ørsted who, in 1820, described how a compass needle was deflected from magnetic north by a nearby electric current, and Michael Faraday who had demonstrated that an electrical current flowing through a coil of wire generates a magnetic field. Wheatstone and Cooke used these properties to devise a system whereby electricity sent down a wire passes through a coil at the far end and the magnetic field generated in the coil then moves a magnetised needle left or right depending upon the direction of electric flow.

Using this basic principle, they devised an instrument that comprised 5 needles arranged on a grid of letters. By moving a combination of two needles any of the twenty letters on the grid could be pointed to and a message read as each letter was indicated in turn. The instrument was operated by pairs of push buttons which would make an electrical connection and cause two chosen needles to move left or right. The great disadvantage of this system was that only twenty letters could be utilised (C, J, Q, U, X and Z couldn't be sent). Also, moving five needles required six electrical connections (five wires plus Earth) which in 1837 was both difficult and expensive to achieve. Nonetheless the system was successfully demonstrated on 25th July 1837 on the London and Birmingham Railway with Wheatstone at Euston and Cooke about nineteen miles away at Camden Town. That system was trialled for a six month period but was never extended or adopted on a permanent basis.

Four needle telegraph

Double needle telegraph

A pair of these instruments was soon installed for use by the GWR between Paddington and Slough. Just over a year later, in early 1845, they played a fundamental role in bringing a murderer to justice, see John Tawell below.

Single needle telegraph

Single needle telegraph

The next, and final, development of the telegraph was the single needle telegraph in the early 1850s. As its name suggests there was just one needle and operating handle (or paddle depending uoon maker) and therefore it required just two connections between instrumentsto make it work, one being the earth. This made it much cheaper to install and maintain. At first the codes for the letters were as shown in this table, which we think might have been carried over from the double needle telegraph. The writing slope seen attached to the instrument has a pin at the top to secure either the message to be sent, or paper upon which to write an incoming message.

Early instruments relied upon seeing the needle move but this was supplemented by the addition of two small sounders which would be struck by the needle. They were tuned to make a different sound, left or right, and so messages could be listened to instead. Single needle telegraphs could be installed in series along a section of railway so that a message sent from any instrument was seen at all the others. The end points in such an arrangement were connected to earth with all intermediate instruments defaulting to complete the circuit. When one instrument was operated its battery would be connected into the circuit with its polarity controlled by the operating lever so causing all the needles to move either left or right.

Eventually, the Cooke & Wheatstone and other complex codes were abandoned and Morse code was adopted as standard by all railway companies. There was no distinction between the length of a dot or a dash, a dot being represented by a left deflection of the needle and a dash by a right deflection. Each letter could also be identified by a combination of the notes produced by the sounders, staff often identifying them more by the tune than by the code. We have in our collection a copy of Telegraph Appendix to the Rule Book from 1906. In it are detailed the rules and regulations concerning the handling of all types of telegraphic communications. The frontispiece carried the explanation that The Instructions printed in ordinary type in this book have been agreed for general adoption by all Railway Companies. The Instructions printed in italics apply only to the Great Western system and to Joint Lines under Great Western control. As can be seen from the extract the single needle alphabet in use is Morse code with 'dots' represented by a left deflection, and 'dashes' represented by a right deflection of the needle.

It might be surprising to learn that single needle telegraphs remained in use for many years with the last ones surviving into the 1970s. They were popular with signalmen as they could listen to messages without having to pick up a phone, they were apparently also paid an extra allowance if they could operate a telegraph.

Morse Code

Alongside the pioneering developments taking place in England, the American Samuel Morse had also been thinking how to achieve the electronic transmission of messages. His ideas were very different to those of William Cooke and Charles Wheatstone whom he had met. Morse realized that although they had built an ingenious mechanism, his own system was far simpler, more efficient, and easier to use. It used an automatic sender consisting of a plate with long and short metal bars representing the Morse code equivalent of the alphabet and numbers. The operator slid a pointer connected to a battery and the sending wire across the bars, and immediately the appropriate dots and dashes were sent over the line. The receiver used an electromagnet with a stylus on the end of an arm. When the magnet operated, the stylus made an impression in a moving paper tape which was then read by the operator. By the end of 1837 he had successfully demonstrated his system in both New York and Washington. It was not until 1843 that he received government funding to build a forty mile long telegraph line between the Supreme Court chamber of the Capitol building in Washington and the railroad station in Baltimore. The first message was sent along the line in May 1844. Soon, overhead wires connected cities up and down the Atlantic coast. The recording of messages on paper strips was replaced by sounds enabling the operator to interpret the code in real time. Telegraph lines soon extended westward, and within a few years had connected the continents of Europe and America by undersea cable.

As hinted above, Morse's code used a series of dots and dashes of differing length to represent numbers and letters. The actual codes underwent a number of refinements over time, resulting in American Morse code and International Morse code amongst others. After some minor changes to the letters and a complete revision of the numerals, International Morse code was standardized by the International Telegraphy Congress in 1865 in Paris, later becoming the standard adopted by the International Telecommunication Union (ITU) and is now commonly referred to simply as 'Morse code'.

The use of Morse code gradually diminished as more modern, and faster, technology became available and so it remains in use in just a few specialist areas such as amateur radio or by historic re-enactors. Just as the series of dots and dashes can be heard as tones or seen printed on a paper tape, so they can be represented by a flashing light. The idea of using a flashing light to transmit a message was first tried out by the Royal Navy in 1867, although this pre-dated Morse code. Signalling with lights was also used during the 1914-18 war as it did not rely on wires which could be cut. Signalling lamps have been refined and developed over time, perhaps the best known is the Aldis lamp. NATO forces use signal lamps when maintaining radio silence, or to prevent evesdropping as direct line of sight is required to read a message.

Patents and public ownership

In 1843 Wheatstone assigned his patent rights to Cooke in exchange for royalties and in 1845 a syndicate created the Electric Telegraph Company. By 1847 the ETC had installed a number of telegraph circuits alongside railway lines and was charging the railway companies for their use. However, the original patents expired in 1851 opening the way for competing telegraph companies. The ETC now had to pay for circuit wayleaves and to reduce these costs, they offered the free use of the telegraph system for railway signalling purposes in exchange. There followed a rapid expansion in the telegraph circuits along railway routes to the major cities. In 1850 the Great Western Railway only had 19 miles of telegraph circuit, that between Paddington and Slough, but four years later this had grown to almost 2,000 miles connecting just over 100 telegraph instruments.

The Telegraph Act 1868 gave the Postmaster General the right to acquire and operate those inland telegraph systems in the UK installed and operated by independent telegraph and railway companies. The Telegraph Act 1869 conferred on the Postmaster General a monopoly in telegraphic communication within the UK. Under this Act, the use of all private circuits except those 'maintained for the private use of a corporation, company or person' became the monopoly of the Postmaster General. Despite strong objections from the companies, the inland telegraph companies were nationalised in 1870 and then operated as part of the General Post Office. The final bill for nationalisation far exceeded the original estimate which had not taken into account the cost of purchasing railway company wayleaves.

John Tawell

John Tawell became known as 'The Man Hanged by the Electric Telegraph'. He had quite a varied life, which eventually saw him returning from Australia with his wife and family in 1838 to live in London. His wife suffered from tuberculosis and died before the end of the year. They had employed a nurse, Sarah, to look after her and, despite remarrying, Tawell began an affair with Sarah having two children together. Tawell installed all three in a cottage near Slough where he paid £1 per week to maintain them. However, by 1844 he was in financial difficulties. He bought two bottles of prussic acid, and on 1st January 1845 visited Sarah poisoning her while sharing a beer, but things did not go to plan. A man in distinctive dark Quaker clothing had been seen leaving Sarah's house that evening shortly before she died. The police quickly found that a person answering his description had caught the 7:42 train from Slough heading for Paddington Station.

Use was made of the newly installed telegraph to contact Paddington describing him thus HE IS IN THE GARB OF A KWAKER WITH A BROWN COAT ON WHICH REACHES NEARLY TO HIS FEET. As there was no 'Q' in the alphabet of the two-needle instrument, the clerk at Slough spelt the word 'QUAKER' as 'KWAKER' which was understood only after several requests to repeat. Tawell was followed after alighting from the train in London, and was arrested the next day in a coffee house. The story gripped the public's attention and his trial was extensively covered in the press. John Tawell was found guilty of murder and was hanged in Aylesbury on the 28th March 1845.

The telegraph instrument from Paddington which was used to apprehend Tawell is kept in the collection of the Science Museum in London.

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