An Introduction to Midland Railway Signalling
In The Beginning
Early railways were essentially derived from the horse-drawn stage coach era, which brought with it many of the practices of that mode of transport. The safety of trains lay almost entirely in the hands of the engine driver and responsibility lay with him to drive his train in such a way as to not conflict with another. They were aided in this respect by policemen employed by the railway company who, among other more traditional policing duties, were tasked with controlling the trains, especially at junctions. There were no fixed signals such as we have come to recognise later, relying instead on conveying his instructions by hand signals, flags and lamps.
The method of keeping trains apart was termed “Time Interval” and in the early days with slow, infrequent train services, a well-spaced timetable fulfilled the objective of keeping trains away from one another reasonably well. As more lines opened and more traffic was generated, a strict rule was that no train could leave a station until at least 10 minutes had elapsed after the preceding departure. This was enforced by the station master and only when he said so could a train’s Guard give the green flag to the driver to proceed. All this assumed, of course, that trains kept to the timetable and didn’t stop between stations. Needless to say, that was not always the case!
Tall fixed “Semaphore” signals — based on longstanding naval practice — were introduced to warn a driver that a train was already standing in a station as they approached and theoretically allowed them to regulate the speed of their approach accordingly. Even the tallest signal remained invisible at a distance, and so “Distant” signals (then termed Auxiliary Signals) were erected sufficiently far away from stations, a long wire being utilised to change their indication.
Until the 1860s, these rudimentary signals and the points that routed trains onto their respective lines were still controlled by policemen, though by then they at least concentrated solely on that task and were relived of fighting crime, checking tickets or apprehending trespassers. As the role evolved, these men were still known as “Bobbies” and, conversely, police officers controlling road traffic were said to be performing “Point Duty” for generations to follow.
The Arrival of Electricity
Although they were far from pioneers in the field, the Midland Railway slowly adopted the electric telegraph, a technology that had been progressively developing through the 19th century, and applied it to a somewhat more robust means of controlling trains. While the North Midland Railway had used a very early method of signalling by electrical impulses through Clay Cross tunnel when it opened in 1840, that was an isolated early example on the Midland. More widespread use of this rudimentary ability to cause a bell to strike individual beats at relatively long distances from the 1860s, allowed communication from station-to-station. The departure of a train from one station could be advised to another to be ready for its arrival, and just as importantly inform the station it had left of its arrival — vitally, complete with all its expected carriages and wagons — so that a further train could follow it in safety.
Slowly but surely, and usually by trial and error as mistakes and omissions resulted in some quite horrifying accidents, a very safe system of “Block Telegraph” working evolved and remains central to railway operation to this day. In short, the railway line is broken up into ‘sections’ and (usually) only one train is allowed to occupy any one section at a time. The complex system of bell codes allowed signalmen to describe the nature of a train and, where necessary as it approached junctions, the direction it was going. Out of course events such as a blockage of the line or other danger such as a door left open in a passenger carriage, could also be communicated by special bell codes. The state of the line — whether it was occupied by a train or was clear for the next train to approach — was indicated by Block Instruments, the indications of which were controlled from either end of the sections, again using electricity to energise newly developed relays and electromagnets.
Interlocking and Lever Frames
Alongside the use of electricity for the Block Telegraph, the single most revolutionary change for railway signalling arrived in the 1870s (and again, the Midland Railway were relatively late adopters) in the form of the interlocking lever frame. In is most basic incarnation, this concentrated all the levers to control signals and points in a given area at a single location and included a mechanical locking that prevents a signal being cleared to ‘All Right’ unless the points in the track were correctly set for the movement to proceed safely, and vice-versa.
Now the ‘Bobby” had truly become a Signalman.
The Signal Box
With all this new fangled and expensive equipment, especially the very sensitive electrical telegraph, a form of shelter was essential (not so much for the signalmen themselves, though they of course benefitted!) and the Signal Box came into being. By 1907 the Midland Railway had 1,925 of them across its then network of 1,688 miles of railway.
To create this number of signal boxes and probably ten times as many signals per box, along with the associated electrical equipment, the Midland Railway created a dedicated workshop at Derby under the supervision of Paul Prince, and later, his son — also Paul. The work of these two men was to have an influence which remains to this day… notably in the form of the Midland Railway’s distinctive style of signal box. Formed of wood panels with large windows and a pitched slate roof, these structures were manufactured in kit form with a series of standard ‘flakes’ which could be bolted together on site to form a signal box of any required size.
This method of construction required substantial timber uprights at each corner of the box and often at 10 or 12 foot intervals along its length in the case of larger boxes. These posts were buried in the ground, an act which would inevitably lead to the wood rotting over time. The Company didn’t care though, as their collective experience was that the railway was growing and growing, inevitably requiring new signal boxes to be erected as the lines grew and covered more ground. The expected useful ‘life’ of a Midland Railway signal box was considered to be around ten-to-fifteen years. This evident folly was reversed in the early years of the 20th century with concrete foundations being provided for new Midland Railway boxes from that time, but the overall design remained relatively unchanged.
Unlike many of its contemporaries, the Midland preferred small signal boxes controlling smaller, more compact, areas. This was also a consequence of their unique design of lever frame where the locking components were mounted at the back of the frame rather than underneath, as was the case with most other companies’ designs. In the latter case, the more levers in a particular frame, the taller the signal box needed to be in order to accommodate all the locking. Conversely, the Midland’s frames rarely had more than 30 or so levers (and always in multiples of four due to their construction method), leading to modestly proportioned signal boxes.
The Signalmen
[An aside, gender specific job titles inevitably applied in the period of history under review and are so used here. Women were employed in the role from the Second World War and of course today Signallers is the appropriate term for the job]
The job of a railway signalman over the 78 years in which the Midland Railway existed, and beyond, evolved quite significantly. It was a skilled and responsible role which required literacy and numeracy as well as a very strong sense of self-discipline and attentiveness. On top of many and various mechanical and electrical aids that were developed over the years to minimise the consequences of human error, the most important was the “Train Register Book” in which the signalman recorded every action they performed. As well as a lasting record that could be audited, it was first and foremost an instant memory aid… vital at any time, but especially in the wee small hours of a winter’s night shift in a pea-souper fog with equipment perhaps not operating as it should — one wrong action had huge potential for multiple loss of life. That is not superlative, it actually happened frighteningly often.
In its own way, the job could be both mind-numbingly lonely, and equally highly social! Signal boxes were often located literally in the middle-of-nowhere with only the passing trains for company, especially at night. In later years, at least there was an antidote to that in what was known as the “Omnibus Circuit telephone”. Ostensibly for ‘official communication’ relating to the running of trains, in effect it was the social media of its day with conversation and gossip being exchanged between all the signalmen along the line in between their dealing with trains. A signalman could know every intimate detail about his ‘mate’ at adjoining boxes, but because they generally worked on the same shift pattern, may barely recognise him if them met in the street off-duty!
Shift patterns were harsh in the early years, with a particular signal box operated around the clock by just two men working 12 hour shifts. Some boxes offered slight relief to the drudgery of constantly rotating between ‘Days’ and ‘Nights’ as Sundays allowed many boxes to be closed (or “Switched Out” to allow trains to pass freely) due to much reduced traffic patterns. Otherwise, on Sunday mornings, the man who had been on duty since 6pm on Saturday would be “Relieved” at 6am by the Day Man, only to return at 2pm. The received man would then go home for a quick rest and return at 6pm to begin a week of 12 hour night shifts. Days off were infrequent and relied on additional “Reliefmen”. By the later years of the 19th century, 10 hour shifts were introduced by the addition of a “Fifth Man” who would split four hours between two boxes, with the remaining two hours allowed for walking between them as required.
Single Lines
So far in this brief look at Midland Railway signalling we have assumed that two lines are provided allowing trains to pass in each direction without issue, but there were many lines, usually in rural areas and less heavily used, where there was only one line shared by trains in both directions. The potential for Very Bad Things to happen is obvious, even with the safeguards of the electric telegraph. Consequently procedures were developed which allowed a train driver to have possession of a tangible “Token” representing their authority to occupy the single line and be assured no other train could come in the opposite direction. Later still, these Tokens could be issued from either end of the single line by the cooperative action of the Signalmen at each end of the Section, locking the machines at both ends so only one Token could ever be out at once. This allowed an imbalance in the working pattern such that more than one train could travel though the section the same direction (but only one at a time!) before a return working arrived in the other.
Thankfully, history records that nothing badly untoward happened on the Midland Railway due to Single Line Working, unlike at Abermule in rural Montgomeryshire on the Cambrian Railway in January 1921. Here, “slack working” (i.e. contrary to the Rule Book) and miscommunication by station staff, combined with fatal inattention by a driver in not checking the token he was given, resulted in a head on crash.
Power Signalling
We have already seen that the progressive introduction of the use of electricity made the railway safer and provided immense flexibility in how signalling systems could be designed and applied. In its purest form, so called Mechanical Signalling relied on a lever being moved in the Signal Box causing a solid rod to push or pull a set of points over, or a long wire to move a signal arm either ‘On’ (“Danger”) or ‘Off” (All Clear or Proceed). This required significant physical effort by the Signalman and there was a finite distance over which these actions could practically work. Indeed, the government agency responsible for railway safety, the Board of Trade, actively prevented railway companies installing points on passenger railway lines which were further than 350 yards from the Signalbox due to safety concerns that they would reliably operate. This was coupled with an innovation called a “Track Circuit” whereby a low voltage electrical current was fed into one of the rails in a line of track. The presence of any wheel and its axle (invariably made of conductive iron or steel) would create a short circuit, so indicating that a train or engine was occupying that section of track. This allowed Signalmen to effectively ‘see-round-corners’ and resulted in many associated advancements on the ways trains could be signalled and controlled. The Midland Railway’s first installation of a Track Circuit was at Mansfield North on 16th December 1905, with over 100 more being installed within five years.
The use of Track Circuits, electrically operated, and more importantly, electrically “Proved” signals and points, allowed signalboxes to control larger and more complex areas and this is the basis of railway signalling throughout the later 20th century into today.
The ultimate development of electrically operated “Power Signalling” is a signal box that solely uses this method and these started to appear in the early years of the 20th century. The Midland Railway ‘dabbled’ in this area, installing just one “power operated Signal Box”, at Way & Works Sidings, south of Derby station in 1905. This system was manufactured and installed by Siemens & Halske, a German company. By 1907 the Midland Railway, evidently concerned at the amount of electricity being consumed, extrapolated from an average 5,000 individual lever movements made in this signal box on a weekday, based on electricity consumption and maintenance costs over six months, that each lever movement cost 0.00496 of a penny, with maintenance being 0.0117 of a penny! By 1932 it is evident that electricity and, especially, maintenance costs had spiralled so the electrically powered lever frame at Way & Works signal box was replaced by a conventional mechanical variety. Thus ended the one and only such experiment on the Midland Railway.
What’s Left
The ten year ‘life expectancy’ for a Midland Railway signal box that is referred to above, was long forgotten by the First World War when, in so many ways, the world changed for ever. The slow but inexorable decline in the fortunes of the country’s railways began and the constant expansion experienced before the War was emphatically reversed. The London Midland and Scottish Railway, the company that took over the Midland’s lines in 1923, accelerated the adoption of electricity. This effected notable efficiencies, gained by closing intermediate boxes as their areas were controlled instead by their neighbours. New designs of signal boxes and new materials like concrete were introduced. The Midland’s last Signal Superintendent was Wilfred Cousins Acfield who retired in 1927 having been appointed to the post in 1906 and firmly stamping his mark on the role. With Acfield’s retirement Derby’s influence on the LMS diminished and production of new signal boxes moved to Crewe soon after with Derby Signal Works closing in 1932.
Power signalling fully arrived in Derby, Nottingham and the Birmingham areas during the summer of 1969 with most of the then surviving Midland Railway signal boxes across an even wider area being taken out of use and demolished. Some did survive in places where traffic that required complex shunting operations so that someone ‘on the ground’ could oversee what was happening,, but as goods traffic reduced and sidings closed, most of these “Shunting Frames” gradually succumbed. The Derby Power Signalbox was in operation for 49 years, being replaced in 2018 by the East Midlands Control Centre, also at Derby, that now controls most of the former Midland Railway south of Chesterfield using computer workstations. Its equivalent centre at York has control of most of the rest of the ex-Midland lines, and much more, in the North.
That all said, it is quite remarkable that even in 2024, and likely for several more years into the future, there remain several Midland Railway constructed signal boxes actively controlling trains on Britain’s national rail network. These include several on the renowned Settle & Carlisle line, in north Derbyshire and Leicestershire and, perhaps most remarkably, Swinderby in Lincolnshire sandwiched between two huge power signalling schemes. There is even a surviving lower quadrant Midland Railway signal, incredibly still controlling express trains and intermodal freights at Ketton on the Syston to Peterborough line. True, its various components have been renewed so many times over the years it is akin to the so-called “Trig’s Brush”, but it nevertheless still a Midland Railway lower quadrant signal and evidently much beloved by the railway operating staff in the area concerned.
Such is the legacy of what Paul Prince senior and his son began.
