Extreme heat house damage?

Spending a lot of time on the adjacent farm as a a kid, and riding on top of a trailer of baled hay, I can well remember the way the HV lines strung on pylons that we passed under, would sag quite noticably during very hot weather.

To be honest the most vulnerable weather to get a fire is may and June. The sun rises higher in the sky, but because the vegetation is dryer in July, that is when left out broken glass etc tends to start fires, or Lightening from the storms of the season does so. We shall gloss over careless smokers and outdoor cooking devices. Brian

Seems to be points and signals that get affected around this branch line when its too hot, too cold and icy or a load of leaves fall off in autumn, how unexpected. Brian

Yes its local buckling that is the problem. You can easily get derailments if the rails cannot slide easily. The trains are already being speed limited in known areas due to the problem as a derailment when slow is inconvenient, but at speed its a disaster. Brian

In some places there has been some subsidence under the tracks, which can be equally dangerous of course. I suspect any damage to houses will only be known in the next few months when the leaks show up.

Brian

Well the inevitable massive thunderstorm that usually ends a heatwave will find all those new cracks in flat roofs that the hot weather created.

Andrew

Jethro_uk used his keyboard to write :

Bridges?

Chris Hogg laid this down on his screen :

The bends/curves get pushed out first.

On the BBC news channel today they showed the same thing, but the Network Rail spokesman added that they expected the rail temperature to exceed 50°C. That would be 23° above the 27° SFT and theoretically contribute to an expansion of around 400 feet in the 300 miles. Even if that's a bit far-fetched, does the rail go back into exactly the same position when it has cooled down and contracted?

Yep.

It's not unusual for roads to exceed 50°C in sunny weather and its not an especially high temperature for rails.

Trains go through the Mojave desert where *air* temps can reach 50°C... It's just another excuse to stir up global warming panic.

My steel gate is 7m wide. At certain times the sun shines on the top half but the bottom half is screened. At those times the gate sometimes slips on the cog wheel that drives it.

Bill

On 16/07/2022 23:45, The Natural Philosopher wrote: <snip>

Meanwhile engineers have for years pointed to buckling caused by hot weather to explain derailments. If that's all been part of some global warming conspiracy some might say it's time to listen less to engineers.

I think that we often forget about unequal expansion, and that can cause all sorts of unexpected issues - not only with metals.

Several years ago I had some new beds and borders made in the garden, and wanted to put in something to keep a clear distinction between them and the lawn. Most things were too expensive, but I came across polythene strip 150mm high and 2mm wide in lengths up to 50m. It came in various colours, and was said to be strimmer-proof (It was. The crap edging in garden centres was destroyed as soon as the strimmer cord touched it.). So I got 100m. Bad mistake. It came in tight rolls which were extremely difficult to unroll, and trying to do a curve against the original roll was almost impossible. I buried about half in the soil, and left the other bit to make the border edge.

It wasn't until summer that the real problem appeared. I had chosen a dark brown colour, and that absorbed heat from the sun very efficiently. So the top half got hot and expanded, while the bit in the soil stayed cool. The result was an uneven scalloped edge depending on how hot the top was. When I checked, I was amazed to find that the coefficient of expansion of polythene was 10x that of iron! Because plastic is generally a pretty good heat insulator, I'd thought it would expand very little. No wonder the stuff distorted so much.

The fact that its been happening '*for years* does indeed show that today's panic is indeed part of a global warming conspiracy.

Of course a long welded rail will buckle if it loses its tie downs, and so bad maintenance shows up in hot weather and is blamed on climate change, that most convenient lie.

Essentially what network rail are saying is 'we have poorly maintained track that may buckle because of it in hot weather'

why dont they have a problem in India, or do they?

You seem there to disagree with the engineers who design the track and lay down the conditions when speeds must be reduced; and tar with the same "poor maintenance" brush others who also impose speed restrictions in heatwaves - eg SNCF in France. Quelle surprise.

AIUI, India limits each CWR section length to 1km. Elsewhere they can be miles long. There's also the issue of relative speed?

PA

I think they also tend to have rather higher /minimum/ temperatures so can set their stress-free temperature higher and get higher maximum temperatures :)

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