Poor communication of heat related speed restrictions

[mrmartin]

Travelled to Cardiff from London on Friday around 12noon; needed to get to an appointment so left myself over an hour to be safe. I checked national rail and GWR twitter and checked departures which all seemed ok.

Unfortunately got stuck in a initially 60mph then 20mph restriction basically the entirity of Swindon to Bristol which made us over an hour late. Maybe stupid of me to have not left more time, but would have been good to put some notices up saying there was likely to be extreme delays around midday? I would have set off far earlier. I was expecting maybe some trouble but not a 20mph speed restriction across a lot of the network - down from 125.

Journey back was a nightmare too with loads of cancellations understandably.

For future reference - does anyone know what temps these ESRs get put in at?

 

[irish_rail]

For future reference - does anyone know what temps these ESRs get put in at?

That depends. Last year on the b and h there were lots of blanket ESRs put in at about 20 degrees and upwards. Depends on state of the track. If the Gov gets its way and defeats the RMT then expect more of these restrictions as maintenance etc is cut back on......

 

[Pugland53]

Travelled to Cardiff from London on Friday around 12noon; needed to get to an appointment so left myself over an hour to be safe. I checked national rail and GWR twitter and checked departures which all seemed ok.

Unfortunately got stuck in a initially 60mph then 20mph restriction basically the entirity of Swindon to Bristol which made us over an hour late. Maybe stupid of me to have not left more time, but would have been good to put some notices up saying there was likely to be extreme delays around midday? I would have set off far earlier. I was expecting maybe some trouble but not a 20mph speed restriction across a lot of the network - down from 125.

Journey back was a nightmare too with loads of cancellations understandably.

For future reference - does anyone know what temps these ESRs get put in at?

That was probably the same train I was on. The reason for the delay between Swindon and Bristol was that we were following two freight trains and they had a heat related speed restriction of 30mph.

 

[mrmartin]

Ah right. Did seem insanely slow - the 60mph made more sense. Thanks.

 

[railfan99]

That was probably the same train I was on. The reason for the delay between Swindon and Bristol was that we were following two freight trains and they had a heat related speed restriction of 30mph.

I am in Victoria, Australia.

On our rural network, the typical 'heat speed restriction' is between 1200 and 2000 hours: 90kmh for passenger trains (assuming 'normal' line speed is 160kmh for some railcars on some lines, or 115kmh for locomotive-hauled passenger trains) but it's only imposed when the forecast is for 36 degrees and above. In practice, only imposed during the hotter part of summer: sometimes won't be consecutive days.

'20 degrees' for 'heat speed restrictions?' 20 is pleasant/mild weather.

 

[43066]

I am in Victoria, Australia.

On our rural network, the typical 'heat speed restriction' is between 1200 and 2000 hours: 90kmh for passenger trains (assuming 'normal' line speed is 160kmh for some railcars on some lines, or 115kmh for locomotive-hauled passenger trains) but it's only imposed when the forecast is for 36 degrees and above. In practice, only imposed during the hotter part of summer: sometimes won't be consecutive days.

'20 degrees' for 'heat speed restrictions?' 20 is pleasant/mild weather.

I think it has been explained on here before that the U.K. has a greater daily range of temperatures than many much hotter countries. The correspondingly greater expansion/contraction of rails is the issue that leads to needing restrictions, despite the relatively mild peak temperatures reached.

Others will be be able to give more detail I’m sure.

 

[2021_Signaller]

I think it has been explained on here before that the U.K. has a greater daily range of temperatures than many much hotter countries. The correspondingly greater expansion/contraction of rails is the issue that leads to needing restrictions, despite the relatively mild peak temperatures reached.

Others will be be able to give more detail I’m sure.

They also use inferior grade steel except on the high-speed lines

 

[Gems]

Travelled to Cardiff from London on Friday around 12noon; needed to get to an appointment so left myself over an hour to be safe. I checked national rail and GWR twitter and checked departures which all seemed ok.

Unfortunately got stuck in a initially 60mph then 20mph restriction basically the entirity of Swindon to Bristol which made us over an hour late. Maybe stupid of me to have not left more time, but would have been good to put some notices up saying there was likely to be extreme delays around midday? I would have set off far earlier. I was expecting maybe some trouble but not a 20mph speed restriction across a lot of the network - down from 125.

Journey back was a nightmare too with loads of cancellations understandably.

For future reference - does anyone know what temps these ESRs get put in at?

Sorry for the sun shining. Maybe it was the wrong kind of sun.

 

[Wolfie]

They also use inferior grade steel except on the high-speed lines

Inferior or differently specified? Australia generally doesn't have to worry about temperatures below freezing let alone below -10C.....

 

[2021_Signaller]

Inferior or differently specified? Australia generally doesn't have to worry about temperatures below freezing let alone below -10C.....

Inferior apparently. Not something I was aware of until a senior manager told me. All about cost

 

[Wolfie]

Inferior apparently. Not something I was aware of until a senior manager told me. All about cost

I'm sure that there are deep experts on the subject on here. Doubtless they will opine in due course.

 

[Stewart2887]

I observed quite a few trains on Friday between Swindon and Didcot doing about 40mph, slow enough to read the destination screens. A couple of very slow freights

 

[Spartacus]

Inferior apparently. Not something I was aware of until a senior manager told me. All about cost

Rail grades are quite a complex subject, far more than "This expensive rail = good; this cheaper rail = bad". A rail that's very resistant to wear's going to be prone to rolling contact fatigue without regular grinding, and vice versa, everything's got merits and drawbacks, and some are going to be more prone to different stresses than others.

 

[al78]

I think it has been explained on here before that the U.K. has a greater daily range of temperatures than many much hotter countries. The correspondingly greater expansion/contraction of rails is the issue that leads to needing restrictions, despite the relatively mild peak temperatures reached.

Others will be be able to give more detail I’m sure.

If normal summer weather conditions cause major problems for the railway, that is poor. Is there any other industry or infrastructure that gets so perturbed by average conditions?

 

[43066]

If normal summer weather conditions cause major problems for the railway, that is poor. Is there any other industry or infrastructure that gets so perturbed by average conditions?

As I say, my understanding is the high to low temp range is the issue. Not sure how we compare to other countries with a similar climate.

@Bald Rick might be able to comment more on the detail.

 

[Taunton]

I think it has been explained on here before that the U.K. has a greater daily range of temperatures than many much hotter countries. The correspondingly greater expansion/contraction of rails is the issue that leads to needing restrictions, despite the relatively mild peak temperatures reached.

Others will be be able to give more detail I’m sure.

Not the case at all. Deserts have a far greater range of daily and seasonal temperatures. The BNSF main line across Arizona regularly gets up to 35-40C in summer by early afternoon, while just before sunrise you may even have frost. In winter they snowplough. They have every sort of rail, from immaculate cwr to dilapadated sidings, but none are impacted by temperature change.

 

[Spartacus]

Not the case at all. Deserts have a far greater range of daily and seasonal temperatures. The BNSF main line across Arizona regularly gets up to 35-40C in summer by early afternoon, while just before sunrise you may even have frost. In winter they snowplough. They have every sort of rail, from immaculate cwr to dilapadated sidings, but none are impacted by temperature change.

Yes they are, and it's very easy to find examples of BNSF trains actually derailed by buckled rails, and that's just derailments, heaven knows how many restrictions get put in place every year. In the last figures I have the US averaged 34 derailments due to buckling annually, with around half a dozen on BNSF metals, there's been huge reports written on the subject, it is a BIG problem in North America, they have in the region of 1000 reported buckles a year: https://railroads.dot.gov/sites/fra...fety_Concepts_Applications_20130321_final.pdf

In 2012 there were 4 accidents in the space of two weeks, one of them fatal, two involving BNSF trains https://www.federalregister.gov/doc...ne-conditions-in-continuous-welded-rail-track

There's no official report into the 2021 Joplin crash yet, but one of the suspected causes is buckling.

Numerous railroads, in fact probably all, have speed restrictions when the ambient air temperature gets too high, and they also have to contend with the issue of tracks being pulled apart by low temperatures and breaking, sometimes cited as the main cause of derailments in North America in winter, something we tend to try and avoid in the UK. There's only so much steel rails will stand, no matter where in the world you are.

 

[Taunton]

There's no official report into the 2021 Joplin crash yet, but one of the suspected causes is buckling.

Well you are not going to get high temperature extremes in Montana at the end of September ... I think they will be looking at maintenance aspects.

 

[Spartacus]

Well you are not going to get high temperature extremes in Montana at the end of September ... I think they will be looking at maintenance aspects.

Buckling, or the risk of it's, still a big problem pretty much anywhere when it's warm though. I've known heat speeds to be applied, or buckles to have started, at some surprising times of the year too.

 

[LNW-GW Joint]

They also use inferior grade steel except on the high-speed lines

My journey last week in 30+ degree heat on Italy's high speed lines was at the regular 300km/h.
I'd be interested to know if there were any heat restrictions on HS1.

 

[Bald Rick]

I have written extensively about this subject on previous threads, so will only summarise here.

The issue for CWR, which is almost all the rail on the network, is the difference between the Stress Free Temperature of the rail (ie the temperature at which the rail has no compressive or tensile forces acting on it, given that CWR is in a fixed position), and the actual temperature of the rail. The actual temperature of the rail is a function of the air temperature, and exposure to sunlight. Today, with air temperatures of 26C, rail temperatures in sunlight will be 45C +.

The Stress Free temperature (SFT) in this country is normally 27C. In other countries it is different.

Rail can cope with temperatures around 30C above the SFT, as long as the track bed is not disturbed. Above that there is a significantly increased risk of buckles. However anywhere there has been recent trackwork causes the track bed to lose its rigidity, and along with several other factors this means the 30C limit above the SFT will be reduced. Furthermore, if new rail is installed and is not at the SFT of 27C, then the rail temperature that risks buckles can be much lower. For example I once imposed a ‘Heat Speed’ in the middle of February: the rail was installed at -5C and not stressed, on new ballast, then the sun came out and we had a rail temp of 17C IIRC.

As a rule, heat speeds *for track* only go on For one of three reasons:

1) recent work to the track, leading to the SFT being lower than normal (it can be much lower)
2) some types of defects in the track, which are judged by the relevant engineer to lead to an increased risk of buckles in hot weather
3) incomplete records of SFT.

I don’t know what has happened on the GWML.

There is also the issue that if there are several heat speeds in close proximity, it becomes difficult to provide boards for them (and multiple restrictions may cause confusion for drivers), hence the application of ‘blanket’ speeds covering a wide area.

If the Gov gets its way and defeats the RMT then expect more of these restrictions as maintenance etc is cut back on......

rubbish. Please stop spreading false information.

They also use inferior grade steel except on the high-speed lines

No ‘they’ don’t. It’s the same steel - indeed the rails used on some French High Speed line is made in Scunthorpe, on the same prodcution line, with the same steel, as is used on NR.

The difference on high speed lines is that a heavier section of rail is often used. This is also the case on heavy freight lines, eg in the US and Russia.

If normal summer weather conditions cause major problems for the railway, that is poor. Is there any other industry or infrastructure that gets so perturbed by average conditions?

Yes, aviation, maritime, etc etc.

They have every sort of rail, from immaculate cwr to dilapadated sidings, but none are impacted by temperature change.

Yes they are. The laws of physics are universal!

They simply accept more buckles in summer, more rail breaks in winter, run at lower speeds anyway, and in some extreme cases they restress the rails in autumn and spring.

 

[Taunton]

Yes they are. The laws of physics are universal!

They simply accept more buckles in summer, more rail breaks in winter, run at lower speeds anyway, and in some extreme cases they restress the rails in autumn and spring.

That's a bit simplistic, and this double/triple track line from New Mexico to California is notably high speed, still having cab signals. For the remaining passenger train it's quite a ride ...!

But you are of course correct about the laws of physics, so they must have managed a way of working with them and combating Sir Isaac Newton. I had always understood that for cwr the key was ballast depth and weight of sleepers/fastenings, plus adequate destressing, to contain things.

 

[Bald Rick]

That's a bit simplistic, and this double/triple track line from New Mexico to California is notably high speed, still having cab signals. For the remaining passenger train it's quite a ride ...!

But you are of course correct about the laws of physics, so they must have managed a way of working with them and combating Sir Isaac Newton. I had always understood that for cwr the key was ballast depth and weight of sleepers/fastenings, plus adequate destressing, to contain things.

its not ballast depth as such (beyond a minimum level which applies on almost all NR lines) but the ballast shoulders. It is all about track restraint, ie stopping it moving. More sleepers helps, as does stronger fixings (Pandrol fast clips and e clips being as strong as anything)

the stressing is, of course, essential in all cases.

out of interest what is the seasonal range of temperspires on that line from CA to NM?

 

[43066]

I have written extensively about this subject on previous threads, so will only summarise here.

The issue for CWR, which is almost all the rail on the network, is the difference between the Stress Free Temperature of the rail (ie the temperature at which the rail has no compressive or tensile forces acting on it, given that CWR is in a fixed position), and the actual temperature of the rail. The actual temperature of the rail is a function of the sir temperature, and exposure to sunlight. Today, with air temperatures of 26C, rail temperatures in sunlight will be 45C +.

The Stress Free temperature (SFT) in this country is normally 27C. In other countries it is different.

Rail can cope with temperatures around 30C above the SFT, as long as the track bed is not disturbed. Above that there is a significantly increased risk of buckles. However anywhere there has been recent trackwork causes the track bed to lose its rigidity, and along with several other factors this means the 30C limit above the SFT will be reduced. Furthermore, if new rail is installed and is not at the SFT of 27C, then the rail temperature that risks buckles can be much lower. For example I once imposed a ‘Heat Speed’ in the middle of February: the rail was installed at -5C and not stressed, on new ballast, then the sun came out and we had a rail temp of 17C IIRC.

As a rule, heat speeds *for track* only go on For one of three reasons:

1) recent work to the track, leading to the SFT being lower than normal (it can be much lower)
2) some types of defects in the track, which are judged by the relevant engineer to lead to an increased risk of buckles in hot weather
3) incomplete records of SFT.

I don’t know what has happened on the GWML.

There is also the issue that if there are several heat speeds in close proximity, it becomes difficult to provide boards for them (and multiple restrictions may cause confusion for drivers), hence the application of ‘blanket’ speeds covering a wide area.




rubbish. Please stop spreading false information.



No ‘they’ don’t. It’s the same steel - indeed the rails used on some French High Speed line is made in Scunthorpe, on the same prodcution line, with the same steel, as is used on NR.

The difference on high speed lines is that a heavier section of rail is often used. This is also the case on heavy freight lines, eg in the US and Russia.




Yes, aviation, maritime, etc etc.



Yes they are. The laws of physics are universal!

They simply accept more buckles in summer, more rail breaks in winter, run at lower speeds anyway, and in some extreme cases they restress the rails in autumn and spring.

Characteristically excellent response, thanks.

While we’re on the subject, here’s another question for you: have you ever been aware or a heat related speed ESR which is “variable” - ie Dalek, warning and commencement boards set up to show either linespeed or a lower speed across a particular junction (110 or 50 in the case I’m thinking of)?

The speeds displayed were changed based on temperature.

 

[Taunton]

out of interest what is the seasonal range of temperspires on that line from CA to NM?

What I can find quickly for Winslow AZ (classic Santa Fe crew change point on the line) is an annual span of about 40-45 C. You do get a substantial daily variation as well, below zero in the morning, baking by afternoon.

Climate and Average Weather Year Round in Winslow Arizona, United States​

In Winslow, the summers are hot, the winters are short and very cold, and it is dry and mostly clear year round. Over the course of the year, the temperature typically varies from -5°C to 34°C and is rarely below -11°C or above 37°C.

It's the fastest Amtrak line outside the Acela northeast corridor, and certainly fastest with diesels. 100 or 110 mph I think.

 

[Bald Rick]

Characteristically excellent response, thanks.

While we’re on the subject, here’s another question for you: have you ever been aware or a heat related speed ESR which is “variable” - ie Dalek, warning and commencement boards set up to show either linespeed or a lower speed across a particular junction (110 or 50 in the case I’m thinking of)?

The speeds displayed were changed based on temperature.

yes, quite common.

there’s two levels of heat speed, 30/60 and 20.

What I can find quickly for Winslow AZ (classic Santa Fe crew change point on the line) is an annual span of about 40-45 C. You do get a substantial daily variation as well, below zero in the morning, baking by afternoon.


It's the fastest Amtrak line outside the Acela northeast corridor, and certainly fastest with diesels. 100 or 110 mph I think.

thanks for that. Similar temperature range as here.

the main intervention that other railways do, particularly where the hot weather is predictable (as I guess Arizona is, and this is certainly the case in southern France, Italy and Spain) is that they do not do any trackwork that disturbs the ballast or SFT in the high summer unless it’s an emergency.

 

[itfcfan]

I have written extensively about this subject on previous threads, so will only summarise here.

The issue for CWR, which is almost all the rail on the network, is the difference between the Stress Free Temperature of the rail (ie the temperature at which the rail has no compressive or tensile forces acting on it, given that CWR is in a fixed position), and the actual temperature of the rail. The actual temperature of the rail is a function of the air temperature, and exposure to sunlight. Today, with air temperatures of 26C, rail temperatures in sunlight will be 45C +.

The Stress Free temperature (SFT) in this country is normally 27C. In other countries it is different.

Rail can cope with temperatures around 30C above the SFT, as long as the track bed is not disturbed. Above that there is a significantly increased risk of buckles. However anywhere there has been recent trackwork causes the track bed to lose its rigidity, and along with several other factors this means the 30C limit above the SFT will be reduced. Furthermore, if new rail is installed and is not at the SFT of 27C, then the rail temperature that risks buckles can be much lower. For example I once imposed a ‘Heat Speed’ in the middle of February: the rail was installed at -5C and not stressed, on new ballast, then the sun came out and we had a rail temp of 17C IIRC.

Thank you @Bald Rick for the clearest explanation I've seen on this topic. I've often wondered how places like Northern Kazakhstan with an air temperature range of ~70C (winter regularly sees temperature of -35C and summer sees temperatures of +35C) copes with rail stress. The rail network certainly operates differently from the UK with freight dominating over passenger and the fastest trains limited to ~140km/hr and significant padding built into schedules with average lengths well over 1,000km.

 

[Falcon1200]

As a rule, heat speeds *for track* only go on For one of three reasons:

1) recent work to the track, leading to the SFT being lower than normal (it can be much lower)
2) some types of defects in the track, which are judged by the relevant engineer to lead to an increased risk of buckles in hot weather
3) incomplete records of SFT.

From my experience (as an operator, not engineer I hasten to add) by far the majority of CRT (Critical Rail Temperature) ESRs (Emergency Speed Restrictions) were imposed at recent track renewal sites, so not fully stressed. So much so that when hot weather was forecast, watchmen were stationed to monitor rail temperature, and (in theory if not always in practice) ESR boards and equipment were in place at the lineside, ready to be installed when the CRT was reached thus minimising delay by obviating the need for Signallers to caution trains until the equipment was provided.

 

[Bald Rick]

From my experience (as an operator, not engineer I hasten to add) by far the majority of CRT (Critical Rail Temperature) ESRs (Emergency Speed Restrictions) were imposed at recent track renewal sites, so not fully stressed. So much so that when hot weather was forecast, watchmen were stationed to monitor rail temperature, and (in theory if not always in practice) ESR boards and equipment were in place at the lineside, ready to be installed when the CRT was reached thus minimising delay by obviating the need for Signallers to caution trains until the equipment was provided.

more likely that the ballast is not fully consolidated, than the rails not being stressed - it can take weeks for the Critical Rail Temperature (CRT) to get up to a decent level, particularly on quiet lines.

there are three levels of mitigation, by increasing level of rail temperature:

CRT (W) - deploy a watchman (watchperson?) to take the rail temperature and visually check for buckles
CRT (30/60) - first level of speed restriction
CRT (20) - second level of speed restriction

CRT (W) is based on forecast rail temperatures, remote monitoring kit and roving watchpersons. The other two are based on temperature measurements on site.

another constraint is the number of people able to be watchpersons, and erect the speed boards. Hence blanket speed restrictions sometimes.