Heat related issues (25 July 2019 and subsequent days)

HOOVER29 said:

It seems that every time the sun has its hat on & it’s lovely and hot this country can’t cope.
Buckled rails everywhere.
How do really hot counties cope.
Australia, India parts of America for instance.
Do their rails buckle or do they treat their rails in some way to combat this problem?
If so could we start doing it?
How much does painting the sides of the rails white help?
Is that the answer?
I’m no engineer & don’t pretend to be so welcome any explanation.

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HOOVER29 said:

I’m just reading that in Pakistan it was 45c yesterday & trains ran normally.
Apparently our Railway tracks are designed to an operating temperature of 27c.
Yesterday we had a maximum of 38.1.
27c!!
That can be a normal summer temperature in this country.
I find that hard to swallow.
This country pioneered railway engineering did it not yet the second the sun rose yesterday Notwork Rail announces that services will have to be cancelled in anticipation of high temperatures later in the day.
In that case why bother with a Railway.
After all the wrong leaf may fall on the track or we might even have the wrong type of snow.
Is this really the same Great Britain?

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As others have said, read my posts earlier in this thread, and the link to a previous thread I put in one of the posts.

In short - other countries have exactly the same problems. The laws of physics apply universally. They combat them in different ways. Some countries do no work to the track all summer. Others (some railroads in the US, for example), are content with a lot more track buckles, and derailments.

Please note this thread is not for ranting and venting your spleen. This is for sensible discussion.

If anyone wants to have a rant please do so into a mirror.

I don't have the time to go back and delete anything off-topic but please note any further posts which add no value will be deleted without further warning. Thank you.

A0wen said:

The "operating" temperature is NOT the air temperature - it's the rail temperature.

And it's a median (go look up how averages are calculated) not the "maximum" - the point NR reasonably have been making is they need the network to be capable of working in both summer and winter most of the time - if you set the network up to accommodate the 1 or 2 days of summer heatwave without issue, there would be immediate failures in autumn at the first frost.

It's not a problem that has been unique to the UK - there were widespread issues across France yesterday as a direct consequence of the heatwave.

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I think I read that the rail temperature is about 20 degrees more than the air temperature.

-Peter

Back on topic.
Finally got back home around 10:30am this morning after giving up at Kings X yesterday. Thankfully being a Thursday I just back to my London rented room and stayed there.

Peter C said:

I think I read that the rail temperature is about 20 degrees more than the air temperature.

-Peter

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Regarding rails' heat stressing, it has to be remembered that the likely range of temperatures to be experienced is what determines the median stress point - so, in the UK, 27C accounts for extreme summer heat (or used to!) and for winter weather down to, say, -15C (broken rails in severe frost are common, though). Rail and air temperatures differ, and ground level temperatures are more extreme at both ends of the range than air temperatures (4-6 feet above the ground). So, if rails were stressed to always allow for 50C levels, they would be unable to cope with winter. On top of that, the rate of temperature change on days like yesterday, from, say, 20C at dawn to 50C+ in the mid-afternoon, is far greater than a gradual night-time cooling from, say, 2C to -10C.

Ever more expansion joints may be needed if rails are to continue to be stressed for our developing range of temperatures.

However, it seems that the problem now is OHLE's reaction to heat, although I am making assumptions here about yesterday's issues.

This is something I should know the answer to, but where services were cancelled last night and so a passenger has had to travel today using the same ticket, where do they stand n relation to Delay Repay? If it had been a case of having to travel on a later service the same day due to cancellation then Delay Repay would be applicable. It’s travelling the next day I’m trying to think through.

Deepgreen said:

However, it seems that the problem now is OHLE's reaction to heat, although I am making assumptions here about yesterday's issues.

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that is a very good point. The majority of the serious issues reported yesterday were OHLE based.

Were there any reports of any rails actually buckling yesterday?

I have not read every contribution, so apologies if this had already been covered, but having suffered very long heat related delays on London Overground from Euston yesterday, and being told that the LUL Met Line was running ok from Watford. Is there any evidence that Network Rail managed the effects of the higher temperatures less well than other UK networks like the Met Line from Hertfordshire to central London?

Peter C said:

I think I read that the rail temperature is about 20 degrees more than the air temperature.

-Peter

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Rail temperature varies to air temperature depending on how sunny it is (ie how much cloud cover), and the time of year. In unbroken sunshine, in May, June or July, Rail temp will be around 18C above air temp. It’s less than this with broken cloud or haze, less still if fully overcast. Any rain cools it down obviously. In spring / autumn, the temperature increase is less fo the same weather conditions, and in winter the effect is negligible.

Deepgreen said:

Ever more expansion joints may be needed if rails are to continue to be stressed for our developing range of temperatures.

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There are no expansion joints in CWR. Hence the ‘Continuosly Welded’ part of the acronym. If the temperature range gets wider than currently allowed for in CWR in this country (which is air temperatures up to 41C, which we have never had in this country), then we will have to consider lifting the stress free temperature by a degree or so.

I was intending to be in London today but in view of the forecast decided it was better just to dial in to the meeting and in fact the client who was travelling from somewhere else did the same. None of the colleagues who attended in person had any objection to this. I decided this on Wednesday on the basis of the weather forecast and expectation that trains would be bad even on the day after such a heatwave. There are probably quite a few other people who can change their arrangements at a day or two's notice and everyone not travelling is one less person to deal with if there is a major incident. Weather forecasts 2-3 days out have improved quite a bit in recent years and most of the time warnings can be put out in time - including this one although the failure mode seems to have been different from expected! TOCs do seem to have been inconsistent in their message, and I do agree that such warnings should automatically allow and include that passengers can travel on reasonable alternative services (not necessarily at the same time the next day) or claim 100% refund if they wish.

Air conditioning is a difficult one. If passenger-openable windows are provided then someone is bound to open them, despite any warning stickers, and render the aircon useless if actually working - probably also making it more likely to fail as it has to work that much harder to get rid of the hot air being brought in. The type of opening window that people can't stick their heads out of (see other recent threads) tends to do nothing to cool the person sitting underneath that opened it, but just creates a draft further down the train as well as a lot of noise at high speed. As a sometime hay fever sufferer I still avoid Class 156 in the early summer, or if I have to use one look for a back-facing seat near the front of a coach. Staff openable windows offer a compromise and it's certainly a good thing that Class 158 had these, as their aircon has proved about the least reliable and in a two-car unit there's often not the space to move to another coach. But staff training has been variable - the window should only be open if the aircon is definitely dead and I've read on here that some people don't follow the correct procedure to shut it down and that increases failures. Also if there is an incident the staff may have things to do before they can get down the train to open windows. Perhaps a compromise would be windows with sealed releases, so passengers could open them but would be reluctant to do so without a good reason?

Andrew1395 said:

I have not read every contribution, so apologies if this had already been covered, but having suffered very long heat related delays on London Overground from Euston yesterday, and being told that the LUL Met Line was running ok from Watford. Is there any evidence that Network Rail managed the effects of the higher temperatures less well than other UK networks like the Met Line from Hertfordshire to central London?

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I’ve been waiting for this to come up.

In a previous post I mentioned that there are three levels of intervention for rail temperatures - first have a watchman on suspect sites, secondly impose a speed restriction of 60mph for passenger trains, thirdly reduce the speed to 20mph. As no part of LU has a speed higher than 60mph, they don’t actually have to make the first two interventions. It is therefore much less likely that heat related speed restrictions will occur on the open sections of LU (although they can, and do happen).

Of course underground, it’s not an issue, as the temperature range is, by comparison to above ground, minimal.

The D.C. line suffered because of the problem at Euston itself. I suspect that the Bakerloo ran fine.

Taunton said:

But there weren't any. None of the roads melted, they had all been adequately designed with tolerances, not minimally specified.

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*None* of the roads? Parts of the A610** outside my house were clearly melting yesterday (ruts and ridges forming). 36C peak here which, while not extraordinary for London, is pretty unprecedented here. All local power + landlines blew out at the peak of the heat, phone out for 18hrs.

**Main road to the M1 in Nottingham.

Andrew1395 said:

Is there any evidence that Network Rail managed the effects of the higher temperatures less well than other UK networks like the Met Line from Hertfordshire to central London?

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I don't think you are comparing like with like. How fast are LU trains?

EDIT - beaten to it

Is anybody able to expand a bit more on how OHLE is designed to cope with the heat, at a similar level to the excellent explanation of track temperatures that @Bald Rick gave in the early posts in this thread?

I see references in this thread and elsewhere to pulley/dead weight tensioning, and also Tensorex units. What are these? How do they work? How do they fail? What are their pros and cons? Is there a physical limit where they will fail above (and below?) a certain temperature like the rails, or is it a compromise of cost against likely temperatures? What are the different compromises made in hotter countries? Was yesterday simply that it was too hot for the OHLE, or did they unfortunately fail due to other reasons?

modernrail said:

On the comparison with those fighting on the beaches of Normany...My Grandad was a Captain in the Royal Army Service Corps, one of the last out at Dunkirk (we think the last Destroyer) and one of the first in on D-Day. Mentioned in Dispatches for bravery in taking in his men to put out a massive fire one of the first fuel ships into Cherbourg. He was nearly captured a number of times but out his foot down on his BSA and shot at a lot, part organised and lay the supply routes for the front line into Bruge and Berlin and endured the horror of being one of the first into a number of concentration camps including Belsen.

He couldn't understand it when people who had never been near a battlefield compared everyday situations with war. As he said many times, people of his generation would and frequently did, 'moan like buggery' when they saw something in the everyday that could have been done better not being done with sufficient care and attention to detail. I think he found it an insulting comparison in the round, somebody who had not been near a pile of burning bodies thinking they had any right whatsoever to invoke the memories of those people in relation to the relatively mundane to make a point of extremely questionable substance.

He also questioned a generation that was gifted liberty, a welfare state and a peaceful Europe making such a poor fist of doing anything particuarly useful or building a legacy for the next generation. 'It is easy to be selfish, self-obsessed and incompetent...it is much harder to do things right and do the right things for people'.

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Blimey! That's far deeper than I was going with my remarks. Without wanting to dwell on this any more, the point i was making was that in the great scheme of things being stuck on a hot train is not the end of the world and far worse things happen at sea.

Its a shame that your grandad perhaps would have found my point about people sensationaling a few hours on a hot train an insulting comparison to his wartime experiences (my point was actually that there is no comparison). The other side of that coin is that my grandfather on one side who fought on the Somme, my grandfather on the other who was in the RAF in WW2, and grandmother who lived through the Blitz in south London used to all get p***ed off with people moaning about minor inconveniences as if they were major hardships. Two sides to every coin. Let's move on.

Bald Rick said:

I’ve been waiting for this to come up.

The D.C. line suffered because of the problem at Euston itself. I suspect that the Bakerloo ran fine.

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My train left Euston ok and then sat at Kensal Green for ages due "heat related problems". Ran very slow to Harrow and then told the train was not to stop at any other stations and would run direct to Watford. I suspect that last bit was to get the unit to Watford for a return working. We got the subsequent DC. I wonder if there were other operational incidents yesterday that used the excuse of the hot weather. As an aside modern units like those on the Met and DC are far more comfortable in the heat. They of course have aircon, but the through design helps as well. I think the concensus is that Network Rail did as well as other networks, on an extreme day.

EMT now saying do not travel all weekend due to the overhead wire problems at West Hampstead meaning a reduced timetable is needed until Monday.

arb said:

Is anybody able to expand a bit more on how OHLE is designed to cope with the heat, at a similar level to the excellent explanation of track temperatures that @Bald Rick gave in the early posts in this thread?

I see references in this thread and elsewhere to pulley/dead weight tensioning, and also Tensorex units. What are these? How do they work? How do they fail? What are their pros and cons? Is there a physical limit where they will fail above (and below?) a certain temperature like the rails, or is it a compromise of cost against likely temperatures? What are the different compromises made in hotter countries? Was yesterday simply that it was too hot for the OHLE, or did they unfortunately fail due to other reasons?

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Too early to say what caused yesterday’s failures.

The OLE is a complex system, and there are many potential points of failure. Even something as simple as a dropper becoming detached (the thin vertical wires between the contact wire and catenary wire) can cause a dewirement if the circumstances are right (or wrong, depending on your point of view!)

However what does tend to happen in very hot weather is that the whole system gets a bit ‘looser’; whilst most OLE is tensioned, it is only the contact and catenary wires that get the tension - the rest doesn’t (headspans, cross contact wires, etc etc). This all means that certain types of defect become more pronounced, and more likely to cause an issue than in ‘normal’ temperatures. There’s a similar effect in very cold weather, where the whole system tightens up.

Clearly in an ideal world there would be no defects in the OLE, but there are always some.

theageofthetra said:

Why every year does AC fail? Why is nothing done?

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And considering the trains are modern newish, you would think that regardless of the heatwave they would work

DarloRich said:

that is a very good point. The majority of the serious issues reported yesterday were OHLE based.

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Not an OLE engineer so this is just as I understand it - the UK legacy (i.e. not installed in the last 5 years or so) wires are at a much lower tension than that used in the EU. This is partly because our wires have to change height a lot more - EU wires are quite flat in comparison, ours have to keep hopping over level crossings or under bridges. Also, our legacy systems were generally designed for trains using only one pantograph - multiple pan operation can require higher tensions so that the leading pantograph does not disturb the wire as much. Higher tensioned wires will sag less at the same temperature. Unfortunately, as much as it would be nice to up the wire tensions, I'm not sure the OLE support structures are rated for the increase.

causton said:

This is how it works. The driver and guard (where applicable) are given an additional stop/not-to-call order form by station staff at stations where possible (sometimes, depending on TOC, location and staff member, they can accept them by direct contract from Control and get the form later) so they have a physical record - as you want the driver and guard to know they're meant to stop additionally/not stop, and you wouldn't want to get to Crewe to find out you're in hot water for not stopping where you should have done if wires have been crossed and you weren't supposed to skip the stations after all! Of course, Stafford is run by Virgin so their staff will hand out the form to the traincrew.

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I just think that it’s laughable that in a situation like this that network rail and staff from other TOCs know more about where a train service thats not theirs is going/not going than the actual staff on the train who really should know first

In a terrible environment thanks to the heatwave it doesnt help matters that onboard train staff don’t what whats happening

43055 said:

EMT now saying do not travel all weekend due to the overhead wire problems at West Hampstead meaning a reduced timetable is needed until Monday.

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I understand workings conditions are gonna be vile in this weather but really? Does it have to take 4 days to fix overhead wires

As regards failure of the air conditioning on trains, or failure of the power supply thereto when the wires come down, I have long felt that trains should be equipped with openable windows for such circumstances.
To prevent needless opening of the windows, I would electrically lock them when the air conditioning is working.
Train crew could remotely unlock the windows when needed.

RealTrains07 said:

I understand workings conditions are gonna be vile in this weather but really? Does it have to take 4 days to fix overhead wires

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Maybe not if there was only one dewirement to deal with, but with the number of problems yesterday, I would think that the repair teams are a bit stretched. I'd rather they didn't rush and got everything sorted ready for Monday.

Bald Rick said:

Rail temperature varies to air temperature depending on how sunny it is (ie how much cloud cover), and the time of year. In unbroken sunshine, in May, June or July, Rail temp will be around 18C above air temp. It’s less than this with broken cloud or haze, less still if fully overcast. Any rain cools it down obviously. In spring / autumn, the temperature increase is less fo the same weather conditions, and in winter the effect is negligible.

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Thanks for the detailed info - it's a case of metal absorbs heat and there's a lot of sun providing this heat. Painting the rails white (the sides at least) can stop the rails from becoming as hot and therefore buckling.

-Peter

Deepgreen said:

Regarding rails' heat stressing, it has to be remembered that the likely range of temperatures to be experienced is what determines the median stress point - so, in the UK, 27C accounts for extreme summer heat (or used to!) and for winter weather down to, say, -15C (broken rails in severe frost are common, though). Rail and air temperatures differ, and ground level temperatures are more extreme at both ends of the range than air temperatures (4-6 feet above the ground). So, if rails were stressed to always allow for 50C levels, they would be unable to cope with winter. On top of that, the rate of temperature change on days like yesterday, from, say, 20C at dawn to 50C+ in the mid-afternoon, is far greater than a gradual night-time cooling from, say, 2C to -10C.

Ever more expansion joints may be needed if rails are to continue to be stressed for our developing range of temperatures.

However, it seems that the problem now is OHLE's reaction to heat, although I am making assumptions here about yesterday's issues.

Click to expand...

Thank you very much for the technical knowledge there. I'm always willing to learn more about this sort of thing.

-Peter

RealTrains07 said:

I understand workings conditions are gonna be vile in this weather but really? Does it have to take 4 days to fix overhead wires

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Are you able to explain what the problem is with the MML wiring and why you think 4 days to fix it is unrealistic? It must be quite serious.

EMT are still running trains out of St Pancras, however they are running to the emergency timetable put in place yesterday meaning there are fewer trains than normal. This means they are advising people not to travel to try and control numbers.

DarloRich said:

that is a very good point. The majority of the serious issues reported yesterday were OHLE based.

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Yes, even a Southern train from London Bridge to Eastbourne (third rail line) was cancelled with this given as the reason on the national Rail website! Mind you the website and associated apps were struggling to keep up with the mayhem even at 10pm last night.

RealTrains07 said:

I understand workings conditions are gonna be vile in this weather but really? Does it have to take 4 days to fix overhead wires

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It will take a long time for NR to fix a lot of wires. You must remember that the conditions are horrible for the workers. How would you like it if you had to work in the hottest weather of the year for hours on end in a relatively dangerous environment (if trains are still running)?*

-Peter

*I know that the railway is a safe place when everyone has training. But even someone who has had all the training available is still vulnerable to being injured or killed due to human error. The railways are blocked and fenced off for a reason.