Trains running at 'reduced temperatures'

[HSTEd]

Perhaps we should just accept that the Laws of physics are universal

Defeatism!

But yes, you are probably correct.

 

[450.emu]

One council is using gritters to spread sand on the roads to stop them melting, and people have been advised not to drive if we hit 40 in London (chance would be a fine thing with Sadiq Khan and 20 zones )

Roads are getting so hot gritters are put on standby in case they melt

The gritters will spread a 'light dusting' of sand on to tarmac surfaces.

metro.co.uk

Hampshire County Council are trialling this method to preserve bitumen on older roads.

Potential temperature in London will be 41°C on Monday, then dropping to 37 for Tuesday as high temps should return to more bearable levels according to BBC weather.

 

[Mugby]

Genuine question - how much was track buckling a problem in the days before continuously-welded track? I presume even welded track isn't really "continuous" and must have some expansion joints somewhere so if (as some predict) we are going to see more, hotter, summer days as global temperatures rise, is there a case for reducing the distances between these joints as track is relaid?

You should read the report about a derailment at Wath, South Yorkshire in 1948.

Not sure how to do a link but just Google 'Rail Accident at Wath Road Junction, May 1948'. Some very informative reading about what was a tragic accident.

 

[swt_passenger]

One council is using gritters to spread sand on the roads to stop them melting, and people have been advised not to drive if we hit 40 in London (chance would be a fine thing with Sadiq Khan and 20 zones )

Nothing new about that use of gritters in hot weather at all though, it’s been done for many years. I suspect ever since the first use of “surface dressing” roads as a maintenance process.

 

[popeter45]

starting to get concerned for mu trip next week on eurostar, i assume hot weater play havoc for HS1?
planned a 2 hour connection in paris and even now getting concerned if thats missed if the train is cancelled

 

[Bald Rick]

starting to get concerned for mu trip next week on eurostar, i assume hot weater play havoc for HS1?
planned a 2 hour connection in paris and even now getting concerned if thats missed if the train is cancelled

if hot weather is a problem on HS2, it certainly will be on LGV Nord and the Paris Metro / RER.

 

[Recessio]

London Underground have been ahead of the game for years here. The tunnels have a permanent temperature of 1,000,000 °C no matter the weather, so the rails are always at the same size!

 

[Ex-controller]

Critical Rail Temperatures, as is the industry term, which mean the need for an emergency speed restriction, can vary according to location and localised conditions. A stretch of track which is sheltered from breeze and in direct sunlight during the middle of the day can regularly cause concern and the air temperature might not even need to be that warm for a speed restriction to be imposed at a particular site. Once a particular trigger point is reached, a watch person will usually be dispatched to the site to take regular temperature readings.

If it’s just one or two isolated locations then passengers may not notice anything, but on a day of widespread high temperatures more locations will be affected with more likelihood of this causing disruption to services.

 

[njamescouk]

brings back memories of schoolboy physics, the force required to resist thermal expansion is the same as the force required to extend the material by the same amount.

youngs modulus something something coefficient of linear expansion yada yada.

I imagine resisting the expansion on the railway is / would be rather difficult.

 

[physics34]

I found that Wikipedia actually has a reasonable article on the subject (at least it looks that way to my untrained eye). There is a picture of an expansion joint too:

Saw an expansion joint earlier near Willesden that was at its 'maximum expansion'. An hour later they stopped clapham to watford services.

 

[Shrop]

I hope you are!

Perhaps we should just accept that the Laws of physics are universal and that in extremes of weather some things change. It is the same everywhere.

Now that we've reached the first of our two "extremely hot" days, we see a huge number of trains either cancelled or running at much reduced speeds, right across the country. This brings to mind a question since I know a bit about physics, although not so much about railway design - how do they keep their trains going in France, Italy, Spain etc. where large numbers of trains also run a lot faster than our maximum of 125mph (apart from HS1), and where temperatures regularly exceed the temperatures that we're getting today? Do they use different (and presumably more expensive) materials for their rails? Or do they do other things which presumably we don't in the UK?

UPDATE - Not to worry #Bald Rick, I've just found your post on another thread which addresses this and which I'll read with interest!

 

[Bald Rick]

Now that we've reached the first of our two "extremely hot" days, we see a huge number of trains either cancelled or running at much reduced speeds, right across the country. This brings to mind a question since I know a bit about physics, although not so much about railway design - how do they keep their trains going in France, Italy, Spain etc. where large numbers of trains also run a lot faster than our maximum of 125mph (apart from HS1), and where temperatures regularly exceed the temperatures that we're getting today? Do they use different (and presumably more expensive) materials for their rails? Or do they do other things which presumably we don't in the UK?

UPDATE - Not to worry #Bald Rick, I've just found your post on another thread which addresses this and which I'll read with interest!

just to further add - as one example - SNCF have had a rotten day today with travel advisories in place of delays, cancellations etc due to the heat.

it is fair to day that the LGVs (and equivalents) do fare better, as they are very modern railways built entirely to modern standards. However I do remember a few years ago SNCF imposing a speed restriction on the whole of the LGVNord, it was the same temperature in Kent and HS1 ran entirely untroubled