Hot weather performance notices in London - at +23C !!!

[Taunton]

I see today large notices up that services may be delayed/cancelled/do not travel, etc, because of "Hot Weather". At midsummers' day weekend. Who would have thought it.

In London today it's maximum ... 23C.

Among the nannying excuses were that overhead wires stretch and expand at high temperatures. This at London Bridge .

 

[al78]

I see today large notices up that services may be delayed/cancelled/do not travel, etc, because of "Hot Weather". At midsummers' day weekend. Who would have thought it.

In London today it's maximum ... 23C.

Among the nannying excuses were that overhead wires stretch and expand at high temperatures. This at London Bridge .

That is around average for the max daily temperature for the time of year in London if not slightly below. I suspect that excuse is a substitute for can't-be-bothered-to-spend-money-maintaining-the-infrastructure-properly or similar. I would also ask if that is the real reason, were the wires failing more frequently last week when it was touching 30C locally in London?

 

[Bayum]

Interesting. A friend was in Stevenage changing for Thameslink to Brighton and it was 28.

 

[Darandio]

Interesting. A friend was in Stevenage changing for Thameslink to Brighton and it was 28.

Which is even more interesting given the maximum recorded temperature today was 24.7 at Heathrow.

 

[800001]

I’m

Which is even more interesting given the maximum recorded temperature today was 24.7 at Heathrow.

more so when forecast showed max 24 at Stevenage for today.

 

[D6975]

The forecaasts seem to be right up the creek at the moment. Here in Bristol the forecasts for the past week all gave max temperatures in the region of 18, but this was clearly pure fantasy, the actual temps have been well above that - mid 20s on most days.

 

[sh24]

Among the nannying excuses were that overhead wires stretch and expand at high temperatures. This at London Bridge .

Which would be relevant for Thameslink services, if not South Eastern or Southern.

 

[Mawkie]

In London today it's maximum ... 23C.

Whenever I've had track inspection workers in my cab they tell me that the rail head temperature is much higher than the advertised "air temperature". Could that be the case for overhead wires too?

 

[Taunton]

Whenever I've had track inspection workers in my cab they tell me that the rail head temperature is much higher than the advertised "air temperature". Could that be the case for overhead wires too?

Well that may all be true. But the normal air temperature today is normal weather temperature in the country for summer months. Unless we are to be told there is something special in current day rails or wires, that's how it always has been.

 

[stuu]

I see today large notices up that services may be delayed/cancelled/do not travel, etc, because of "Hot Weather". At midsummers' day weekend. Who would have thought it.

In London today it's maximum ... 23C.

Among the nannying excuses were that overhead wires stretch and expand at high temperatures. This at London Bridge .

Rails are stressed to a temperature of 27 degrees, which is rail temperature, not air temperature. Rails in strong sunlight on warm/hot days like today will easily exceed that temperature. In the past there were far less warnings of potential disruption, but that doesn't mean there wasn't actual disruption.

About a third of the train service at London Bridge is Thameslink services, which, as you know, are dual voltage.

Would you prefer not to be told that things may go wrong?

 

[Bantamzen]

Rails are stressed to a temperature of 27 degrees, which is rail temperature, not air temperature. Rails in strong sunlight on warm/hot days like today will easily exceed that temperature. In the past there were far less warnings of potential disruption, but that doesn't mean there wasn't actual disruption.

About a third of the train service at London Bridge is Thameslink services, which, as you know, are dual voltage.

Would you prefer not to be told that things may go wrong?

We get temperatures like this every single year, it's not as if it's something new the railways have to deal with. Sure if the temps went into the 30s I could start to understand why there might be issues, but 23? That's just pathetic.

 

[DynamicSpirit]

Would you prefer not to be told that things may go wrong?

I think I'd prefer to be told that on days when there is something exceptional that means things are particularly likely to go wrong. If those kinds of announcements are being made on normal days when there is nothing particularly exceptional happening (and 23C is not exceptional) they will just end up becoming like background noise that everyone ignores.

 

[Snow1964]

Would you prefer not to be told that things may go wrong?

Not really, because there would be permanent notices with long lists

There might be cancellations due to staff shortages
There might be problems due to points or signals
There might be a windy day
etc etc......

Shouldn't be deeming normal seasonal weather into an extreme event that only happens once a decade category.

Notices that become norm, and not just when orange or red weather warnings (not the milder yellow warning) should be avoided.

 

[Belperpete]

I suspect that it is not the absolute temperature, but the sudden swing in temperature. Generally it has been quite cool recently.

 

[John Bishop]

How do they manage in Europe where they have cold winters and hot summers? The temps they get a generally a lot higher than we ever see, yet they seem to manage a normal service on very hot days. Genuine question!

 

[800001]

How do they manage in Europe where they have cold winters and hot summers? The temps they get a generally a lot higher than we ever see, yet they seem to manage a normal service on very hot days. Genuine question!

They manage, maintain, and install infrastructure to a different standard to what we do, relative to there country.

 

[John Bishop]

They manage, maintain, and install infrastructure to a different standard to what we do, relative to there country.

Well, whilst not trying to state the bleeding obvious, is that not what we should be doing in this country?

 

[LLivery]

Well, whilst not trying to state the bleeding obvious, is that not what we should be doing in this country?

Particularly in the South. 30C is a standard August summer heatwave in London every year, seems a bit odd that low 20s is problem.

 

[Ediswan]

Which is even more interesting given the maximum recorded temperature today was 24.7 at Heathrow.

Official temperatures are measured inside a Stevenson screen, usually sited in a grassy area. Forecasts are for these temperatures.

Locally, anywhere that amounts to a 'sun trap', such as large areas of concrete and tarmac, can be considerably higher.

 

[red cuillen]

How much of a role does air temperature play in how hot metal becomes? Just wondered whether full sun when the sun is at its strongest around midsummer might be the overriding factor??

 

[poffle]

For the overhead wires they are heated by the electricity going through them, the hotter the cable is the more it sags. The actual direct sunlight on the cable probably isn't a major factor. The main factors would air temperature, humidity and wind speed which impact on the ability of the overhead wire to cool.

If the trains operate at lower speed then they draw less current and so the wires will sag less. This was a minor part of why there were some global speed restrictions across the rail network on days in July 2023. ( Rail temperature being the major issue.)

As with anything the equipment is designed to operate within a certain range. Generally the bigger the range the more it costs.

 

[12LDA28C]

I believe these warnings are triggered when temperatures are predicted to exceed 25 degrees, which of course is not unusual at this time of year.

 

[al78]

Official temperatures are measured inside a Stevenson screen, usually sited in a grassy area. Forecasts are for these temperatures.

Locally, anywhere that amounts to a 'sun trap', such as large areas of concrete and tarmac, can be considerably higher.

This is true but if heat related problems somewhere can start happening when the air temperature reaches 23C, that would mean at least half of the days and likely more in a good summer would see those problems, but we don't generally have significant disruption due to heat until the temperature gets into the high 20's, so what was special about the day in question? Any infrastructure should be able to cope with the local climatology, we don't see significant or even minor damage to buildings during 40-50 mph gusts (except maybe badly constructed or decaying ones) during autumn and winter for example.

== Doublepost prevention - post automatically merged: 30 Jun 2024 ==

How much of a role does air temperature play in how hot metal becomes? Just wondered whether full sun when the sun is at its strongest around midsummer might be the overriding factor??

Intensity of sunlight, duration of sunny conditions, lack of wind and local buildings which are shaped to reflect sunlight onto the ground I expect would be optimal for enhancing the temperature of rails.

== Doublepost prevention - post automatically merged: 30 Jun 2024 ==

Well, whilst not trying to state the bleeding obvious, is that not what we should be doing in this country?

In an ideal world but given we keep getting told there is no money, it is better to do it on the cheap and externalise the consequences (which don't appear on the balance sheet apart from maybe some small delay repay costs).

 

[Bald Rick]

How do they manage in Europe where they have cold winters and hot summers? The temps they get a generally a lot higher than we ever see, yet they seem to manage a normal service on very hot days. Genuine question!

They manage, maintain, and install infrastructure to a different standard to what we do, relative to there country.

Actually, with a few exceptions, they don’t do anything different, not least because the laws of physics are the same over there as they are here

What is different is that here in the UK we don’t hear about the delays they have due to hot weather in Europe. (why would we?) And I can assure you they do have them. I’ve been in Paris when the RER was in meltdown (pun intended) due to weather in the 30s; similarly speed restrictions on the LGVs. Also I’ve experienced massive delays in New York / New Jersey / Maryland due to heat.

How much of a role does air temperature play in how hot metal becomes? Just wondered whether full sun when the sun is at its strongest around midsummer might be the overriding factor??

At this time of year, rail temperature can be 18-20C warmer than air temperature.


Edit: just heard from a couple of friends travelling by train in Europe today - delayed over three hours by severe weather…

 

[Belperpete]

How do they manage in Europe where they have cold winters and hot summers? The temps they get a generally a lot higher than we ever see, yet they seem to manage a normal service on very hot days. Genuine question!

They manage because they don't expect everything to keep running normally, and make allowances, leave earlier, check what is happening and adjust their travel plans accordingly. Whereas over here, we have no end of numpties driving hell for leather regardless of the motorway being covered in ice and visibility down to next to nothing, and going to catch their usual train despite a no travel advisory being given.

 

[DynamicSpirit]

They manage because they don't expect everything to keep running normally, and make allowances, leave earlier, check what is happening and adjust their travel plans accordingly. Whereas over here, we have no end of numpties driving hell for leather regardless of the motorway being covered in ice and visibility down to next to nothing, and going to catch their usual train despite a no travel advisory being given.

Do you have any evidence for those assertions that people are more careless about travel in the UK compared to the continent?

I'm not sure how you'd measure peoples' attitude to travel by train, but as an attempt to assess whether - as you assert - we drive more dangerously, I just looked up the traffic-related death rates (on wikipedia) and the figures seem to put the UK broadly in line with the rest of Europe. (3.8 deaths per billion miles travelled in the UK, compared with, say, in 5.8 France, 4.2 in Germany, in the 4.7 Netherlands, 3.3 in Sweden). So it doesn't look from those figures like your claims are true.

 

[Belperpete]

Do you have any evidence for those assertions that people are more careless about travel in the UK compared to the continent?

I'm not sure how you'd measure peoples' attitude to travel by train, but as an attempt to assess whether - as you assert - we drive more dangerously, I just looked up the traffic-related death rates (on wikipedia) and the figures seem to put the UK broadly in line with the rest of Europe. (3.8 deaths per billion miles travelled in the UK, compared with, say, in 5.8 France, 4.2 in Germany, in the 4.7 Netherlands, 3.3 in Sweden). So it doesn't look from those figures like your claims are true.

My experience of working and living in various foreign climes, such as Sweden and Portugal.

Your simplistic look at the figures makes the big assumption that they are down to one difference. I was comparing their attitude to driving in bad weather, whereas you are comparing overall death rates regardless of weather. No wonder the figures are meaningless.

I am surprised that Sweden for example doesn't have much higher death rate on the roads than we do, as I have been truly frightened at some of the things they do. They drive very differently in bad weather, but not necessarily in a good way. When my taxi driver used the ice to make a controlled skid across the motorway, for example, my heart was in my mouth. There are other factors in play that affect the overall death rate,bsuch as their more compliant attitude to laws and social norms, and their less crowded roads, that will undoubtedly affect the overall accident rate.

But not once while I was living in Stockholm did I hear one person complain about bad weather causing disruption. Bad weather happens, and it causes disruption, that is life, deal with it, was pretty much the attitude.

 

[mpthomson]

My experience of working and living in various foreign climes, such as Sweden and Portugal.

Your simplistic look at the figures makes the big assumption that they are down to one difference. I was comparing their attitude to driving in bad weather, whereas you are comparing overall death rates regardless of weather. No wonder the figures are meaningless.

I am surprised that Sweden for example doesn't have much higher death rate on the roads than we do, as I have been truly frightened at some of the things they do. They drive very differently in bad weather, but not necessarily in a good way. When my taxi driver used the ice to make a controlled skid across the motorway, for example, my heart was in my mouth. There are other factors in play that affect the overall death rate,bsuch as their more compliant attitude to laws and social norms, and their less crowded roads, that will undoubtedly affect the overall accident rate.

But not once while I was living in Stockholm did I hear one person complain about bad weather causing disruption. Bad weather happens, and it causes disruption, that is life, deal with it, was pretty much the attitude.

It's not 'simplistic' at all, it's how these figures are recorded for comparison purposes. Your anecdotes aren't evidence. UK roads are currently the third safest in Europe behind Sweden and Switzerland. They're significantly safer than Spain's and road deaths in the UK are just over half that per population than Portugal's. There are no stats for purely driving in bad weather but I strongly suspect that if there were they wouldn't back up your assetion either, as the UK has a lot of bad weather that affects driving compared to, say Portugal.

In Sweden people are just used to driving on snow and ice as it's very common in winter.

 

[Ridgeblog]

I suspect that it is not the absolute temperature, but the sudden swing in temperature. Generally it has been quite cool recently.

They keep saying that a supposed heat wave will come but they keep changing dates on when it will happen in the south east of London. The weather forecast has been quite inaccurate for me recently.

 

[stevetay3]

Which is even more interesting given the maximum recorded temperature today was 24.7 at Heathrow.

I think the official figures given out at places such as airports are shade temperatures and it can be quite higher in the full sun,it certainly is in my garden. I think but stand to be corrected that it is something to do with the mercury in thermometers that get overheated in the heat and then not work accurately.