Why have semaphore signals & boxes mostly been replaced

[Philip]

Why have most signal boxes and semaphore signals been replaced by colour light signals and signalling centres on the UK railways? There were many high-speed lines using semaphores and boxes even until relatively recently and, unlike heritage trains, they're not pollutants. Just seems to be unnecessarily cutting railway heritage and jobs, since the traditional signal-box role is more or less redundant now.

Would you like to see a gradual reinstatement of traditional boxes and semaphore signals, on main lines as well as branch lines?

 

[The Planner]

Why have most signal boxes and semaphore signals been replaced by colour light signals and signalling centres on the UK railways? There were many high-speed lines using semaphores and boxes even until relatively recently and, unlike heritage trains, they're not pollutants. Just seems to be unnecessarily cutting railway heritage and jobs, since the traditional signal-box role is more or less redundant now.

Would you like to see a gradual reinstatement of traditional boxes and semaphore signals, on main lines as well as branch lines?

Absolutely not. Its not a musuem. How many signal boxes with semaphores are you going to need to maintain a 3 minute headway on the WCML, ECML, GWR etc and where is the money coming from? Have you been on the Sherry a bit early?

 

[brad465]

Tradition is an excuse to keep lazy thinkers in line.

 

[Transilien]

Semaphore signals won’t go away after the last one is taken down from mainline railway. There are heritage railways for the very purpose of preserving the heritage that can’t exist efficiently on the mainline.

 

[Philip]

The railways managed with semaphores and boxes for 100-150 years, why are they unsuitable now? If a semaphore has a preceding caution signal why is it unsuitable for fast or busy stretches of line?

 

[Magdalia]

Why have most signal boxes and semaphore signals been replaced by colour light signals and signalling centres on the UK railways? There were many high-speed lines using semaphores and boxes even until relatively recently

In this part of the world most main lines lost their manual signalling 40-50 years ago. I'm old enough to remember when there were signal boxes at Shelford, Shepreth Branch Junction, Cambridge South, Cambridge North, Coldham Lane Junction and Chesterton Junction, six boxes in as many miles. Back in the 1960s there were also Trumpington and Barnwell Junction. It was incredibly labour intensive. In days of high unemployment that might have been an argument for retaining manual signalling, but now it would be very challenging to recruit and retain the number of signallers needed.

 

[LowLevel]

Why have most signal boxes and semaphore signals been replaced by colour light signals and signalling centres on the UK railways? There were many high-speed lines using semaphores and boxes even until relatively recently and, unlike heritage trains, they're not pollutants. Just seems to be unnecessarily cutting railway heritage and jobs, since the traditional signal-box role is more or less redundant now.

Would you like to see a gradual reinstatement of traditional boxes and semaphore signals, on main lines as well as branch lines?

Not in a nasty way Philip as we are all there to some degree but you really were "born too late" as they say - another thread yearning for the resurrection of yesteryear.

No is the answer. I am a preservationist - I love mechanical signalling, I work signalboxes as a hobby and as part of that I've had a hand in the destruction of quite a few signalboxes to donate parts etc.

They're Victorian technology which have been on the way out for 100 plus years.

Having a person in a shed every mile or so is not sensible. They survive where they do because it's made sense for technical or economic reasons thus far but you're not going to be seeing a 390 negotiating a full size LNWR signal gantry at Rugby.

They've been replaced because they're hard to see at night or in fog, they feature maintenance heavy moving parts, producing the spares needed is a lost art and would be hugely expensive and so on.

 

[HSTEd]

Just seems to be unnecessarily cutting railway heritage and jobs, since the traditional signal-box role is more or less redundant now.

Who do you propose pays for the enormous signaller establishment necessary for a semaphore based system?

It would many many billions in additional subsidy, given railway pay levels.
It would also provide no additional capability and would further stymy the necessary move to cab signalling.

 

[Harpo]

Mechanical boxes only disappear when they can’t do what the railway needs as it’s modernised for speed, capacity, electrification etc..

15 years ago there were still over 100 survivors from each of the 4 decades prior to WW1, simply because they’re simple, incredibly robust, very rarely go wrong, do what their bit of railway needs and cost less than a third of a resignalling scheme to refurbish them.

 

[Dr Hoo]

By modern standards single-staffed signal boxes are extremely poor for staff welfare in terms of not being able to take a refreshment or other personal needs break ‘off the tools’. They are also extremely vulnerable to individual staff members being sick, unable to start car to get to work, etc.. with most remaining locations being fringe boxes, controlling level crossings, junctions and so on.

 

[John Webb]

The preserved St Albans South mechanical box was closed in December 1979 and at that time handled nearly 300 trains over the 24 hour period, including 24 in the 8am-9am peak hour and 23 between 6 and 7pm. We now have over 600 trains a day passing the box giving a vastly improved service and there's just no way the 1970s mechanical system could cope with the present day number of trains.

 

[InkyScrolls]

Why have most signal boxes and semaphore signals been replaced by colour light signals and signalling centres on the UK railways? There were many high-speed lines using semaphores and boxes even until relatively recently and, unlike heritage trains, they're not pollutants. Just seems to be unnecessarily cutting railway heritage and jobs, since the traditional signal-box role is more or less redundant now.

Would you like to see a gradual reinstatement of traditional boxes and semaphore signals, on main lines as well as branch lines?

Would I like that? Yes. But do I live a hundred years ago? No. I'm fortunate in that I live in predominantly semaphore area however.

 

[SynthD]

It would be cheaper to put a semaphore on a tv controlled by in cab signalling. This tv could be repeated throughout the train for the passengers who want it. That's far more visible than putting them in actual signalling locations.

 

[Halifaxlad]

You could have made a better argument rather than sounding like its a proposal to sound nostaligic.

Recently all services were temporarily suspended when the signalling system went down near Rochdale due to an power cut.

The Harrogate line between Harrogate and York is full of traditional boxes that cost an awful amount to run. Its also makes the line rather unreliable as it impacts the section from Harrogate to Leeds which got upgraded to color lights many years ago.

More local control might be better for when things go wrong but I wouldnt bring back semaphores.

 

[Llanigraham]

You could have made a better argument rather than sounding like its a proposal to sound nostaligic.

Recently all services were temporarily suspended when the signalling system went down near Rochdale due to an power cut.

The Harrogate line between Harrogate and York is full of traditional boxes that cost an awful amount to run. Its also makes the line rather unreliable as it impacts the section from Harrogate to Leeds which got upgraded to color lights many years ago.

More local control might be better for when things go wrong but I wouldnt bring back semaphores.

And I can think of 3 occasions where Hereford to Shrewsbury, which is all small semaphore type Boxes, has had to close when a signaller was taken ill.
Small isn't aways best!
One of the main reasons small Boxes have been moved to a more central control unit is economics. Even if that "big" Box has Grade 8 signallers it is still cheaper than having 50 signallers at Grade 2 or 3.

 

[Monarch010]

To extend this discussion further into the future, how long before lineside signals are replaced by in-cab alerting, and beyond that, drivers are replaced by computers in a centralised command centre?

 

[InkyScrolls]

To extend this discussion further into the future, how long before lineside signals are replaced by in-cab alerting, and beyond that, drivers are replaced by computers in a centralised command centre?

I doubt drivers will ever be replaced on the mainline. The costs and safety loss would be astronomical.

 

[gg1]

The railways managed with semaphores and boxes for 100-150 years, why are they unsuitable now? If a semaphore has a preceding caution signal why is it unsuitable for fast or busy stretches of line?

The railways also managed 100-150 years or more with on train toilets which emptied human waste onto the track (and any trackworkers unlucky enough to be standing in the wrong place at the wrong time) and carriages with separate body and underframe which are lethal in a major accident to a degree modern stock isn't.

Good riddance to those too.

 

[Halifaxlad]

I doubt drivers will ever be replaced on the mainline. The costs and safety loss would be astronomical.

What they will probably do is try to combine roles so trains will always have a member of staff on board who can take over but wont neccesarily need to be behind the driving seat all the time. I believe the new trains for the Glasgow subway have been designed like this.

 

[InkyScrolls]

What they will probably do is try to combine roles so trains will always have a member of staff on board who can take over but wont neccesarily need to be behind the driving seat all the time. I believe the new trains for the Glasgow subway have been designed like this.

An interesting thought, but the WCML, or the London commuter lines, or the West Highland Line, are all very different from the circular, closed loop of the Clockwork Orange!

 

[The exile]

Ultimately, the simple answer is that mechanical signalling will survive on National Rail as long as there is no financial or operational reason to replace it. As technology progresses the number of places where that applies will diminish (as it has already been doing for over 100 years) and the opposite of economies of scale and lack of availability of trained staff will push more and more areas over that line. The process has only slowed somewhat over recent years as a) earlier electronic-signalled areas have themselves required complete renewal and b) what's left has become more "niche". The last places standing will probably be fringe areas where there are no staff savings to be made as they would either still be needed on site anyway or where removal of the last box would push the local electronic area over the limit that the existing staffing level can cope with. There's been a thread somewhere about what people reckon will be the last pocket of semaphore - I go with Bognor Regis or Littlehampton.

 

[6Gman]

The railways managed with semaphores and boxes for 100-150 years, why are they unsuitable now? If a semaphore has a preceding caution signal why is it unsuitable for fast or busy stretches of line?

What combination of semaphores would you suggest for 4-aspect signalling?

Would these "modern" semaphores have lamps as bright as colour light signals? If so, why add arms?

 

[30907]

The railways managed with semaphores and boxes for 100-150 years, why are they unsuitable now? If a semaphore has a preceding caution signal why is it unsuitable for fast or busy stretches of line?

The earliest signals were at Corbetts Lane outside London Bridge. They were installed around 1840 and replace by colour lights around 1926, which is 85 years. The first colour lights were 10-20 years earlier IIRC.

 

[Falcon1200]

Why have most signal boxes and semaphore signals been replaced by colour light signals and signalling centres on the UK railways?

How many manual signalboxes, and therefore signallers, would be required to control, for example, the West Coast Main Line in Scotland? Whereas today the entire route, from the Route Boundary north of Gretna Junction to Glasgow Central is controlled by a handful of staff in one location. The efficiencies are simply enormous.

 

[Philip]

I understand the arguments about boxes being labour intensive and not cost effective, but just focusing on the suitability of semaphore signals for fast, busy lines. In theory would it be possible to have 4-aspect semaphores to allow 125mph running at 3-minute headways, and could semaphores be controlled from a signalling centre; by means of devices in the structure programmed and activated remotely to raise or lower the signal arm?

 

[InkyScrolls]

I understand the arguments about boxes being labour intensive and not cost effective, but just focusing on the suitability of semaphore signals for fast, busy lines. In theory would it be possible to have 4-aspect semaphores to allow 125mph running at 3-minute headways, and could semaphores be controlled from a signalling centre; by means of devices in the structure programmed and activated remotely to raise or lower the signal arm?

So really what you're asking is whether it's possible to have physical arms under TCB signalling? In which case the answer is 'yes', and in some instances that could actually prove helpful (for example if a signal is prone to being obscured by the angle of the sun, having a physical arm can improve distinguishing of the aspect). Is such a change practical, however? Emphatically no.

 

[Bald Rick]

Looking forward to seeing how many signalboxes and semaphores are needed to control the Thameslink core on 75 second signalling headways.

The preserved St Albans South mechanical box was closed in December 1979 and at that time handled nearly 300 trains over the 24 hour period, including 24 in the 8am-9am peak hour and 23 between 6 and 7pm. We now have over 600 trains a day passing the box giving a vastly improved service and there's just no way the 1970s mechanical system could cope with the present day number of trains.

Indeed so. And when you do the full simulation of the intense service from ‘back in the day’, you can see how it would be completely impractical to run the current levels of service on most intercity and commuter lines with Sempahore signalling.

 

[BazingaTribe]

Aside from staff welfare by being alone, you'd also have people now prone to distraction. Not in the typical 'modern attention spans are similar to those of goldfish' but crew resource management and psychology have advanced a lot more. Devastating situations like the Tenerife incident in 1977 showed not only issues in the cockpit with authoritarian captains, but ATC teams distracted by a football match on the radio of all things.

Maintaining the sort of box sterility that modern operations would require means you'd probably have to rotate personnel more frequently. ATC shifts are very short (there's also the Überlingen disaster, where chaos and short staff caused the infamous mid-air collision; the ATC worker in question was actually knifed by a distraught man whose other family was wiped out in the crash) and pay attention to concentration and focus needed.

The series of devastating accidents in the 1980s across the transport world was the catalyst for much of modern health and safety legislation as one patch after another had to be applied to compensate for the increasing demand, disposable income and leisure time that put fatal pressure on a lot of aging infrastructure that hadn't been designed to cope with the pressure. I am a bit of a nervous flier, because the sensation of take-off is nerve-wracking on a primordial level, but one look at the runway from the Heathrow car park and you'll see that ATC has the concentration and focus to do their job properly because others have made the mistakes and lessons have been painfully learned.

Going back to mechanical semaphore because it looks neat would be like going back to pre-Lockerbie baggage handling and pre-9/11 security because it's too much hassle to spend 10-20 minutes on procedures that have saved lives. It can't happen simply because you like the way it looks -- it would have to be driven by absolute necessity and I'm not sure there will ever be that sort of pressure to go backwards.

 

[HSTEd]

Looking forward to seeing how many signalboxes and semaphores are needed to control the Thameslink core on 75 second signalling headways.

I think the endless series of signal boxes would require another tunnel dug next to the running lines.

 

[Iskra]

There are some examples of newly constructed semaphores replacing life-expired ones fairly recently, so I suspect they will still continue to exist on the network for some time to come.