Weather disruption Sunday 17th July and following few days

[175001]

Heads up about the first Amber warning of the year issued by the Met Office regarding next weekends heat.

The models yesterday were showing a "feels like" 47C in some parts of the south east last night.

By today the models have relaxed a bit but still showing mid to high 30s.

Typcial, I've got to make it down south from Manchester on Sunday for a morning flight from STN on Monday

 

[Bletchleyite]

The reason it's a problem in the UK and not e.g. Spain is that our welded rail is stressed for more typical UK temperatures and not the very high ones you get in countries that are hot for more than a week or so a year. Thus when it gets really hot it expands too much and buckles.

If climate change makes more of our summers really hot, we'll need to revisit that.

 

[175001]

Indeed.

I'm sure there will be blanket speed restrictions due to track temps and OLE sagging etc

 

[Bletchleyite]

Indeed.

I'm sure there will be blanket speed restrictions due to track temps and OLE sagging etc

And 80x overheating

I'd not plan a journey on the Marston Vale either...

 

[al78]

I don't think "feels like" is relevant when it comes to overheated rails. Actual temperature is probably more important.

At least one numerical model (admittedly one of the frequently outlandish ones) is predicting 36-37C next weekend, and there are hints of model runs predicting in excess of 40C.

Met Office press release about the extreme heat warning:

Extreme heat warning issued

The Met Office has extended an Amber Extreme heat warning, as temperatures look to build later this week and early next week for much of England and Wales.

www.metoffice.gov.uk

“Some models have been producing maximum temperatures in excess of 40C in parts of the UK over the coming weekend and beyond. At longer time scales temperature forecasts become less reliable, so whilst these figures can’t be ruled out, they are still only a low probability. A number of weather scenarios are still possible and at the current time, mid- or perhaps high-30s are looking more likely.”

The reason it's a problem in the UK and not e.g. Spain is that our welded rail is stressed for more typical UK temperatures and not the very high ones you get in countries that are hot for more than a week or so a year. Thus when it gets really hot it expands too much and buckles.

If climate change makes more of our summers really hot, we'll need to revisit that.

We ought to revisit it now. 30+C is recorded somewhere in the UK virtually every year, and frequency of hot days in the UK has increased over the last 50 years. If the stressing is done to deal with what the climate was like a century ago, it may not be adequate now, never mind in 50 years time.

UK and Global extreme events – Heatwaves

Determining the likelihood and severity of extreme events for the past, present and future.

www.metoffice.gov.uk

 

[londonmidland]

With high temperatures expected this week, along with a Amber Met Office weather warning for extreme heat for Sunday (17/07), there will no doubt be disruption across the network.

This morning there was a small fire between London Victoria and Brixton, as a result of timber beams having been ignited by a spark.

There has been very little rain across the majority of the country, with little to none forecast for the next few days, increasing the risk of lineside fires.

 

[SCDR_WMR]

Are there many speed restrictions in place? Don't have any on my routes yet...

 

[Snow1964]

Anyone know what temperature are the rails and overhead cables are stressed to, so that speed restrictions aren’t needed, there is presumably a threshold temperature that determines if any might be imposed.

It is looking like it will be very hot in weeks time

Some weather models are expecting a hot plume being dragged up from France, between next Sunday and Tuesday (19th) with temperatures in Home Counties and Cambridgeshire getting upto 37c or even briefly upto 40c. Whilst the models might be overcooking it, does look hot.

Image shows GFS weather model expected temperatures for Tuesday 19th at current time, with temperatures SE of line from Somerset to Norfolk between 37 and 40c

imgur.com

Discover the magic of the internet at Imgur, a community powered entertainment destination. Lift your spirits with funny jokes, trending memes, entertaining gifs, inspiring stories, viral videos, and so much more from users.

imgur.com

 

[Nova1]

There's been a fair amount of disruption today because of the weather between Birmingham and Stratford-Upon-Avon because of heat related temporary speed restrictions, including only one train in four hours...





It was also on local news - https://www.bbc.co.uk/news/uk-england-coventry-warwickshire-62121174

UK heatwave: Hot tracks blamed for West Midlands rail disruption
​

Rail passengers are facing disruption to some services, with an operator blaming hot tracks.
Some trains between Stratford-Upon-Avon in Warwickshire and Kidderminster in Worcestershire would be cancelled on Monday, West Midlands Railway said.
High track temperatures meant fewer trains could run due to a speed restriction, the firm added.
The disruption is expected to last until about 20:00 BST, affecting services in both directions.
Passengers who were delayed would be compensated, the operator said.
Temperatures in the West Midlands are expected to reach about 30C (84F) on Monday.
Direct sunshine can cause steel rails to become 20C hotter than the air temperature, according to Network Rail.
Temporary speed restrictions are introduced during hot weather as slower trains put lower forces on the track and reduce risk of buckling.

 

[dk1]

I think it would be foolish to expect any travel plans over the next week or so to be trouble free regardless of the mode of transport used. It’s not going to be pleasant.

 

[krus_aragon]

Some weather models are expecting a hot plume being dragged up from France, between next Sunday and Tuesday (19th) with temperatures in Home Counties and Cambridgeshire getting upto 37c or even briefly upto 40c. Whilst the models might be overcooking it, does look hot.

Eurgh, and I have to drive down to the London area in that time period. At least I'll be able to head straight back to the relative cool of the North Wales coast...

 

[Mikw]

One thing to remember is the temperature of the rails will be hotter than the ambient temperature if baked in the sun

 

[Snow1964]

Surely the photo caption is wrong way round

Trains will run at reduced temperatures in the hot weather to try and prevent rails from buckling

Isn’t it the passage of trains disturbs the air around the rails, thus bringing in cooler ambient air (rather than air heated by the hot rails), so helps cool the rails. Thus really want to run trains faster (and ideally less streamlined ones like freight trains) to prevent buckling rather than fewer trains, or slower trains

UK heatwave: Hot tracks blamed for West Midlands rail disruption

Services between Stratford-Upon-Avon and Kidderminster are affected amid plans to reduce buckling risk.

www.bbc.co.uk

 

[Ken H]

One thing to remember is the temperature of the rails will be hotter than the ambient temperature if baked in the sun

I woukd have thought rail temp would be because of light from the sun converting to heat when it hits the metal, not air temps. Of course the cooler the air the more it cools the metal.
Why dont they wet the rails at vulnerable places?. Converting water to water vapour takes a lot of energy. Latent heat. Use a weedkiller train perhaps.

 

[cuccir]

When would people anticipate new timetables or other ammendments to services being announced? Is it likely to be any sooner than the day before? I'm travelling to Paris for work and am considering getting an earlier train down to London on the Sunday, but don't know if it would be wise to wait and see what changes LNER make to the ECML service (or indeed Eurostar to theirs).

 

[Islineclear3_1]

I woukd have thought rail temp would be because of light from the sun converting to heat when it hits the metal, not air temps. Of course the cooler the air the more it cools the metal.
Why dont they wet the rails at vulnerable places?. Converting water to water vapour takes a lot of energy. Latent heat. Use a weedkiller train perhaps.

Beat me to it...

Water sprinkler trains, can't a tank in the sandite units be repurposed to carry water? At least this might reduce the risk of fires...

 

[Bletchleyite]

Beat me to it...

Water sprinkler trains, can't a tank in the sandite units be repurposed to carry water? At least this might reduce the risk of fires...

I'm not sure water on oil fires (which is what they mostly are - third rail sparks igniting dripped oil from trains) is going to be much help.

 

[Islineclear3_1]

I'm not sure water on oil fires (which is what they mostly are - third rail sparks igniting dripped oil from trains) is going to be much help.

But water on dry timbers would

 

[RichJF]

I believe the latest forecasts have the most extreme heat Sunday night into Monday - Tuesday. Some models going for 40-41 in Eastern England somewhere.

 

[Bald Rick]

Anyone know what temperature are the rails and overhead cables are stressed to, so that speed restrictions aren’t needed, there is presumably a threshold temperature that determines if any might be imposed.

Rails in this country are stressed to be stress free at 27C. However immediately after installation (ie before stressing) and following any work that disturbs the ballast, and certain local conditions can reduce this stress free temperature - often considerably.

In good quality, undisturbed track, that is straight, flat bottomed rail (109 or thicker), and on concrete sleepers of at least 26 per length or slab, Mitigations are required when measured rail temperature is 32C above the Stress Free temperature (ie 59C) and the first speed restriction is required at 37C above the Stress Free Temperature (ie 64C).

At this time of year, rail in direct sunlight can be up to 20C hotter than ambient. So you can see that good quality, undisturbed track of the type mentioned above that has been correctly stressed will not need any mitigating actions until air temperature is 39C.

Heat based speed restrictions occur because the track is one or more of:

lower specification (eg one or more of on timber, steel, bullhead rail, wider sleeper spacing)
curved track
not good quality
recently disturbed (tamped, stoneblown, manually ‘shovel packed’)
subject to subsidence or voiding
short of ballast
rail not stressed to 27C

each of these have factors to apply to the stress free temperature, for example a curve between 400m and 800m radius effectively brings the temperature required for mitigations down by 7C. Timber sleepers reduce it by 9C. Recent tamping brings it down by 12C.

This, of course, means you need to keep detailed records of all of this stuff, and any gaps in the records means you have to assume the worst case.

EDIT:
having done some research, I’ve found that Spain uses an SFT of 27C, France uses 25C; USA uses a variety of temperatures depending on the temperature range at the location concerned.


I’m tempted to say “it’s that simple” …. But it isn’t, really. (I’ve tried to make it as simple as possible).


OLE is not stressed to a temperature as such. You can tell it’s too hot when the balance weights are on the floor…

 

[Dave W]

I’m tempted to say “it’s that simple” …. But it isn’t, really. (I’ve tried to make it as simple as possible).

Superb summary; greatly appreciated

 

[Islineclear3_1]

Rails in this country are stressed to be stress free at 27C. However immediately after installation (ie before stressing) and following any work that disturbs the ballast, and certain local conditions can reduce this stress free temperature - often considerably.

In good quality, undisturbed track, that is straight, flat bottomed rail (109 or thicker), and on concrete sleepers of at least 26 per length or slab, Mitigations are required when measured rail temperature is 32C above the Stress Free temperature (ie 59C) and the first speed restriction is required at 37C above the Stress Free Temperature (ie 64C).

At this time of year, rail in direct sunlight can be up to 20C hotter than ambient. So you can see that good quality, undisturbed track of the type mentioned above that has been correctly stressed will not need any mitigating actions until air temperature is 39C.

Heat based speed restrictions occur because the track is one or more of:

lower specification (eg one or more of on timber, steel, bullhead rail, wider sleeper spacing)
curved track
not good quality
recently disturbed (tamped, stoneblown, manually ‘shovel packed’)
subject to subsidence or voiding
short of ballast
rail not stressed to 27C

each of these have factors to apply to the stress free temperature, for example a curve between 400m and 800m radius effectively brings the temperature required for mitigations down by 7C. Timber sleepers reduce it by 9C. Recent tamping brings it down by 12C.

This, of course, means you need to keep detailed records of all of this stuff, and any gaps in the records means you have to assume the worst case.



I’m tempted to say “it’s that simple” …. But it isn’t, really. (I’ve tried to make it as simple as possible).


OLE is not stressed to a temperature as such. You can tell it’s too hot when the balance weights are on the floor…

Very good explanation, cheers

So when the excuse of bucked rails comes in, I can assume the rail temperature is 39 degrees or thereabouts.

There are a lot of curves on my line however...

 

[Bald Rick]

So when the excuse of bucked rails comes in, I can assume the rail temperature is 39 degrees or thereabouts.

you can assume that at least one of the other factors is in play…

 

[londonmidland]

The peak of the heat is now expected Monday/Tuesday as opposed to Sunday.

Current max temperatures forecast:
Sunday - 32 degrees
Monday - 36 degrees
Tuesday - 38/39 degrees

The highest temperatures will be towards South East, Eastern & North Eastern and Central areas, however everywhere will be hot.

After that is uncertain, however some models are hinting for a thundery breakdown.

 

[Efini92]

you can assume that at least one of the other factors is in play…

Is there much bullhead rail left?

 

[Snow1964]

Is there much bullhead rail left?

Very rare (if any) on mainlines, but still existing on parts of lightly used lines and many sidings

 

[Ken H]

Is there much bullhead rail left?

Surely Bullhead will be jointed with fishplates and gaps? So theoretically should not buckle. Providing the gaps are properly maintained.

 

[DarloRich]

I can assume the rail temperature is 39 degrees or thereabouts.

I would say you can assume that at least one of the factors set out in the posting by @Bald Rick has occurred. I suggest that the % of track in tip top "showroom" condition is well below that requiring enhanced mitigations!

I might ( bravely) go further and say that the OHLE is more likely to be the cause of any heat related disruption.

 

[Bald Rick]

I might ( bravely) go further and say that the OHLE is more likely to be the cause of any heat related disruption.

that is a very brave statement!

 

[DarloRich]

that is a very brave statement!

I know. The heat has made the wiring in my brain sag