British Transport Films Collection | Volume 8 | Points & Aspects | 1974

Published by Darron Toy on

Carstairs Junction Scotland a bit of a backwater to judge by the signal box some might say but they'd be wrong for this Junction is vital it lies on the west coast main line linking London and Glasgow it's part of a mammoth project to Rhys ignore all the way from Glasgow over the rugged rolling country to the south and on through industrial Britain to a point near Warrington there to join the already modern ice route to London designing building and installing all the equipment which will replace many hundreds of boxes like this one will take over three years to carry out in the drawing offices the two years of preparator work is in full swing the planning and designing of every function the five boxes will perform in their control areas the main scheme plan has already been drawn up it's the key to the whole project for from it Springs all the complex stages of preparation the main specification signal sighting programs cable route planning and later the voluminous control tables these designate the functions of every one of the hundreds of points and signals from these tables the wiring diagrams are drawn up and then begins the long intricate process of checking and rechecking in parallel with all this production can begin in the factories and the sooner the better for the shopping list is a long one item 1600 signal eggs intricately assembled lined up and tested over a thousand point machines both cog and belt-driven all proven and perfect over 60,000 relays and relay units now the signal relay is the key to safety on the railway and because it must always failsafe its design and performance has to be to an extremely exacting standard for example contacts are cleansed in an ultrasonic bath of our clumpy and dried in thermostatic vacuum ovens the contacts are silver – silver impregnated graphite to avoid any possibility of contacts welding together in service to ensure that the armature immediately drops away if current fails or is switched off the cause out of a particular iron which retains no magnetism as time goes on manufacture and installation will go forward together production building up just ahead of demand on the site as we shall see as we move between factory and track in fact a great deal is already happening out on the track cable Lane for instance had been in full swing for some time several cables can be laid at the same time power signal and telecom cables carried on different drums on the same train the work continues through the season every kind of weather having to be faced to keep up with strict schedules armored cables are often used where they have to leave the trophy and they're exposed to arduous conditions all the cables are cut to length at the factory and wind off the drums right up to a location with a foot or two for termination of course here at Motherwell the boxes had to be built on top of an embankment in spite of the clever equipment around today and the wit and adaptability of the human machine is clearly best when faced with a job like this on the other hand the manufacture of cable is very skilfully carried out by machines this is going to finish up a signal cable the copper is first drawn down in several stages to the specified gauge then it remains in vacuum annealing ovens for 24 hours before receiving its coat of tea the cores are numbered 1 to 12 or whatever numbers to form the finished cable so that each can be identified in use insulation is of high-grade rubber sheath with poly chloroprene here 12 cores are being laid up brought together through a die and wrapped with plastic tape this is then fed into the vulcanizing tower wear a rubber extruded sheath is applied and this is vulcanized under pressure in steam filled tubes housed in this tower structure this is power cable for core solid aluminium PVC insulated the single cores are fed through the PVC plant which provides the individual insulation the drum twister laying up machine is charged with four drums of these single cause they're feds would die and twisted by rotation of the hall after my careful control the force sector shaped cause are made to sit together to form the circular section within the die they then bound together with transparent tape by now a variety of other jobs were going ahead all over the railway carried out over and under and between trains all that work might see map hazard it was in fact tied to very detailed plans when the engineers had tracked possession for one job like this it meant that others could install point machines or sight signals unmolested by passing trains all the work involved in designing and building this control panel had to a plan so that it was ready for delivery on a specific date this is part of the Warrington panel the first of the five meanwhile back at the factories the production lines have been carefully scheduled to match the increasing demand from the sites these are plug-in geographical units so called because the geography of the circuits directly relates to the layout of the functions they control on the ground these frames are designed to guide the operators as they route the wires in a variety of patterns a small tape control device indicates a routing code for the girls to follow the circuitry of these cards is photo etched onto the base red if the various components to me fitted in wild after inspection they run over flux and solder waves which solder the component wiring into the printed circuit the temperature is very accurately controlled to produce good joints without damaging the minut components the finished cards themselves become sub assemblies for the next stage in this case chain describer equipment equally fascinating is the production of signal man's control panels these are made of a mosaic or Domino units small assemblies which control and display conditions on the track over which the panel operates the whole forming a mimic diagram of the area a range of individual units provides displays push buttons rotary switches and so on the front tiles are either stenciled or etched with the legend which relates to the function of the equipment to be fitted behind it the whole panel is patiently built-up mosaic by mosaic on the framework and all the pre wiring carried out and tested in the factory here in the Motherwell box part of the control panel has already arrived from the factory this box will operate points and signals over the long lonely track running south to the English border systems of remote-control use either time or frequency division multiplex techniques depending on the amount of information which has to pass they extend the arm of the signalman by allowing many controls or indications to pass along single pairs of wires time division multiplex is generally used to link remote but large control areas and deploys an electronic scanning system which identifies the code of input messages verifies and acknowledges them and routes them to their right destination where they carry out their many functions the FDM system usually caters for individual functions along the way and one type uses sets of mechanically tuned vibrating reeds oscillating to exact frequencies to identify and transmit information highly selective receivers respond only to the matched frequency identifying the message and then allowing it to be accepted extremely careful tuning of the reeds is fundamental to the accuracy of the system equipment is housed in newly built location cupboards and relay rooms along the way our old friend Castor's Junction will have its own new equipment and so the old blocks work they wanted anymore there's another interesting feature of the area between Motherwell and the border as an interim measure local control systems using much of the new equipment in nearby relay rooms were set up in some of the old boxes ready over a year before the completion date of the main scheme this enabled these areas to be commissioned and come into service on their own in contrast work is progressing fast on a rather larger installation at Preston one of the three boxes in the north of England instead of a panel six feet long this one is nearer 75 feet long belowstairs in the relay rooms a massive connections which could not be pre-wired in the factory have to be wired up here the possibility of error would seem formidable but the principle of prefabricating and testing so much of the circuitry in the factory greatly reduces the likelihood of a mistake here standard plug boards fit the framing into which a variety of pre-wired and testing units can be plugged here's a geographical unit finding its proper place upstairs cable connections between control panel and relay rooms are laid out ready to be plugged in a hundred and eighty miles to the north in the huge glasgow central box a unique technical situation had arisen new in 1960 it now has to take on still further responsibilities which means a lot of fresh equipment including a new control panel in order that two groups of specialists could work without disturbing each other part of the control floor had to be partitioned off leaving the signal and on one side still running the railway with the old equipment and the technicians on the other installing the new route set up on the old panel now show up on the new one too that is one of the miniature cathode ray tubes which display train numbers as a train passes its progress is simulated by the number which jumps from window to window across the diagram but now train description is computer-based here the equipment is on tests at the works before being sent to the site the computer which controls the system carries both the main program and many subroutines each of which has a particular function such as to display a number clear it transmit it to another box automatic train reporting is an extra facility which this equipment can provide use is made of the train information present in the system and its relationship to timed train movements past key points the system extracts and selects information as to position and speed and forms it into messages which are passed to operators in such a way that each receives only information useful to him this is in the form of a printout by electronic thermal printers linked to the computer information on demand is available to operators by keying simple codes on their teleprinters every function of the TD system has to be proven as simulated trains pass over one route after another their progress checked visually and monitored electronically as the Scottish contract neared completion it was time to remove the local display panels from the old boxes south of mother well and make reconnections so that the mother whale power box would take over control of the area the funeral aspect of the procession is a little inverted for in truth the contents of the coffin are very much alive whereas it's the mausoleum it came from which is doomed in the relay room final reconnections to Motherwell are made and then the technicians move on to other areas finally with the master switch setting on the caster's panel turned from local to master control the last of the relay rooms along the Scottish section comes under the umbrella of Motherwell but the equipment must still be tested on-site a loco is run through the area aspect set reset and checked with control 6:13 it's okay the commissioning ever power box is a much more complex affair this is one of the major weekends at Carlisle once upon a time the commissioning of boxes was a hectic affair nowadays the pre wiring and testing of groups of components in the workshop has removed much of the cliff-hanging atmosphere of old the pummel in the cavalry signal box that will show you where the joint is four to one forty to one point two one five by down and by right seven eight eight okay yeah yeah let's have a go then extinct 19 and 20 right okay I'll jump in jump you bet now then so you should be okay now how did I lie now my right hand switch both ends as daylight and the first morning trains crept towards Carlisle the job drew to an end by dint of a lot of hard work and not a little caring everything seemed to work and why shouldn't it complicated as it was and so the objective was achieved the Reis ignoring of a thousand track miles used by many hundreds of trains every day all controlled from just five boxes inside a completed box a route is set sending out impulses to point some signals over great distances in split seconds equipment in the relay room checks conditions on the track before setting the route and signaling the Train [Applause]


Lee Wilson · July 31, 2019 at 10:46 am

My uncle was a cable layer back in the 70s.I used to run around my nan's garden wearing his hi-viz vest!!

Gerald Berliner · July 31, 2019 at 10:46 am

My brain hurts

Bubbles DeVille · July 31, 2019 at 10:46 am

This fried my brain…..all those wires! I was born after these peeps had installed this stuff and they made it look so easy!

Mersey Merlin. · July 31, 2019 at 10:46 am

Very interesting documentary. Is this system still in use or upgraded to digital ?

C17H25N · July 31, 2019 at 10:46 am

On Preston platform do your soft-shoe shuffle dance.

PADDYDOYLE · July 31, 2019 at 10:46 am

Love these films.

andy thompson · July 31, 2019 at 10:46 am

Makes you wonder however they managed it, where ever they started it all off and how did it all to fit in and link up together too! Very complex work indeed

Peter Cross · July 31, 2019 at 10:46 am

Take a softly spoken guy and play lousy music over him.

airscrew1 · July 31, 2019 at 10:46 am

That title music was used in The Sweeney as incidental music.

Rex Remedy · July 31, 2019 at 10:46 am


Steve Smith · July 31, 2019 at 10:46 am

Thanks for uploading this… it's absolutely fascinating and quite amazing that the design and build was done with very little computer technology. I can't work out if the music should belong to a crime thriller or porn movie

eric williams · July 31, 2019 at 10:46 am

i was 16 or 17 when this was made, i feel old…………..i AM old!!!

Michael Craig · July 31, 2019 at 10:46 am

It's heartening for an old analogue technician to see good reliable electromechanical and proper purpose designed circuitry at work.

predatorfe · July 31, 2019 at 10:46 am

They really went out of their way to design and build these systems back then, without the aid of Microprocessors and all the other Hardware, and most importantly the Software we have today.
An Age where Mechanic, Electric, Electronic and Computing Sciences were starting to melt together!
Very interesting indeed.

Jersey Mike's Rail Videos · July 31, 2019 at 10:46 am

Still not sure why the British went with such pricy centralized interlocking schemes instead of more flexible CTC systems.  Not only is CTC cheaper, it allows for bi-directional operation as well.

Jersey Mike's Rail Videos · July 31, 2019 at 10:46 am

Still not sure why the British went with such pricy centralized interlocking schemes instead of more flexible CTC systems.  Not only is CTC cheaper, it allows for bi-directional operation as well.

plezurhounds · July 31, 2019 at 10:46 am


John B · July 31, 2019 at 10:46 am

Great film. Always preferred these more technical BTF productions compared to those poetic travelogues of Wales and Scotland. I really must buy more of the excellent DVDs.
And I'd love to know which music library the music at 27:26 is from, groovy!

James Petts · July 31, 2019 at 10:46 am

It is fascinating to see just how different that these things had to be before modern computing – the massive relay room filled with individual wires, each one manually laid! And reed switches…

RanHam335 · July 31, 2019 at 10:46 am

I wonder how long this system was in use.

Pillowcase · July 31, 2019 at 10:46 am

every single aspect of this video blows my mind

Pillowcase · July 31, 2019 at 10:46 am

Awesome hand tattoos 15:43

Sam Horler · July 31, 2019 at 10:46 am

I'm amazed at 8:00, angling huge bobbins to get the sector shaped cables to line up.

darkerjim · July 31, 2019 at 10:46 am

Where would you get any of the music like the stuff on this video?

Toast · July 31, 2019 at 10:46 am

all… those… wires…

George Ferrocarril · July 31, 2019 at 10:46 am

Really fascinating movie on building signal equipment and layout.

appliance004 · July 31, 2019 at 10:46 am

Oooh..dark tunes.

collexions · July 31, 2019 at 10:46 am

26:20 Just my personal bookmark 🙂

collexions · July 31, 2019 at 10:46 am

12:38 I reckon this'll be the section right up your allan!? Ruddy Good Un'!

collexions · July 31, 2019 at 10:46 am

Ooh Yeah, wuvsks!

appliance004 · July 31, 2019 at 10:46 am

11:21 tune, nip

Leave a Reply

Your email address will not be published. Required fields are marked *