signal failures, less common now than in the past?

[infobleep]

This morning there was a signal failure between Clapham Junction and London Waterloo. I was coming from Guildford and at Woking they detrained a load of people and put them on our train. The disruption currently showing as continuing until 4pm, so it must be something big that failed.

Once I got to work I asked a colleague who comes from Earlsfield about his journey and he simply went to Tooting instead to avoid it. I then asked if signal failures were worse now than in the past and he said 10 years ago it was more common.

This got me thinking, are signal failures less likely today, compared to say 25 years; 50 years ago; 75 years ago etc. What about coloured lights v semaphore?

 

[GB]

By the nature of modern signalling I'd say it's alot more prone to failure then days gone by and at a busy location such as clapham the ripple effect is alot more pronounce.

 

[ChrisCooper]

I think faiures are less common, but their effects when they happen are much bigger. The latter is due to the larger areas covered by single signal boxes, the additional traffic on the network, and changes to proceedures for dealing with problems.

 

[Cherry_Picker]

It is difficult to measure. I would say on the whole things are getting better if you remove "one off" factors like teething troubles caused by new software after a major resignalling project, Evergreen 3 springs to mind there.

Maintenance is definitely lower than it ever has been. Fewer moving parts is always good, and colour light signals are affected by wear and tear than mechanical semaphore ones. Expanding and contracting of cables and linkages during extreme heat or cold weather is a problem for semaphore boxes, and colour light signals dont need a man with a jar of paraffin to top them up every couple of weeks. LED signals are an improvement on incandescent bulbs too, not only are they brighter and more vibrant than the old style signals they last a hell of a lot longer too. A network rail guy told me that an old bulb has a working life of a few thousand hours, LED signal heads are expected to last at least 15 years between failures. This is why shunt signals at sidings which are in out of use sidings (plenty of examples around the country) have been replaced by LED lights, because in the long run it is cheaper for Network Rail due to increased reliablilty and lower maintenance.

The other thing which needs discussing though is theft. Scrap metal prices are through the roof at the moment so cable theft is rife. This is one of the biggest causes of signal failures today and it has to be considered.

 

[HSTEd]

If anything happens about Network Rail implementing that Optical LAN based signalling system in future resignallings that should help with the cable theft problem as the only cables on trackside to steal will be the power ones.

It also makes resignalling an awful lot cheaper as well as all that you need to do is ensure that every signalling "device" is plugged into the LAN somehow and the software will ensure that the correct signal gets to the correct place.

 

[Toots]

'Signal Failure' is often cited on media outlets as the cause for delays when it is in fact cable theft..which of course leads to signal failure.A couple of the previous posters have alluded to this,but I would say it was easily the major cause of such 'failures'...signal failures in the 'normal' sense (if you'll pardon the pun!) are rare, although points failures do occur from time to time for various reasons.

 

[swt_passenger]

'Signal failure' in the media translates to 'signalling system failure' - and that can be anything to do with signalling - not just 'signals'.

A small but relevant point.

 

[Bald Rick]

In this case it was the complete failure of Panel 1 at Wimbledon ASC, due to some routine work on it overnight not quite going to plan.

To answer the original question, signal failures in all their guises are less frequent, however with more services on the network, the effect of each failure in terms of delays is worse.

 

[ralphchadkirk]

And for right or wrong, Network Rail no longer has the resources to hand signal and point wind at major failures.

 

[infobleep]

Thanks for the interesting replies. I wonder if people being paid not as good a wage as now is the reason they were able to employ more people years ago to hand signal.

I guess it makes sense. More trains; more people and 1 centre controlling it, all must surely lead to larger scale disruption at the times when things don't work correctly. Of course this is outweighed by all the times it does work and is efficient for the number of trains running.

I mentioned to my brother in law about fog signalmen and he'd never heard of them. I said what do you do if visibility is below 200 yards on a line with semaphore signals? He said just use your local knowledge. Of course we don't have smog like we use to.

I tend to lump everything in the signalling system under the general signal heading. Therefore if a cable theft causes a signal to go down, I'd see that as a signal failure although technically it may not be. That's not to say I'd blame the railways, it's just how I visualise the broad concept.

 

[Yew]

about the new optical cables, do they have optical signal cable written on them. as im sure ive herd of a case where theives realised the cable they had cut was an optical one (and not copper) and had then just scarpered, causing loads of disruption.

 

[Old Timer]

about the new optical cables, do they have optical signal cable written on them. as im sure ive herd of a case where theives realised the cable they had cut was an optical one (and not copper) and had then just scarpered, causing loads of disruption.

Optical cables carry computer data communications links. Most signalling cables are copper and carry electrical signals not computer data.

 

[HSTEd]

about the new optical cables, do they have optical signal cable written on them. as im sure ive herd of a case where theives realised the cable they had cut was an optical one (and not copper) and had then just scarpered, causing loads of disruption.

You should be able to tell them apart, as it would be a single rubber coated strand whereas conventional signal cables probably tend to come in bundles more than anything, either way they could probably get ones with "Optical Cable" written on them.

Just like the original Cat5E standard said the ethernet cables had to be yellow.

 

[Bald Rick]

about the new optical cables, do they have optical signal cable written on them. as im sure ive herd of a case where theives realised the cable they had cut was an optical one (and not copper) and had then just scarpered, causing loads of disruption.

That rather assumes the idiots doing it can read.

 

[Paul180]

That rather assumes the idiots doing it can read.

You will find you do not need to read what's on the cable as the weight is a dead give away between fiber and copper , but most of the thieves haven't even managed to figure it out yet.

 

[TDK]

You will find you do not need to read what's on the cable as the weight is a dead give away between fiber and copper , but most of the thieves haven't even managed to figure it out yet.

Oportunists wull pull up tree roots if they look like cables, does not matter what you do they will always try to steal it, I say put 1000 volts through it, that will stop them

 

[Bald Rick]

Oportunists wull pull up tree roots if they look like cables, does not matter what you do they will always try to steal it, I say put 1000 volts through it, that will stop them

Unfortunately even 25kV doesn't stop them.