Reducing derailment by decreasing track movement by painting the does of the track white, to reflect heat absorbed from the sun.

In a somewhat related practice, some roads in the Tour de France this year have been painted with "white shit" (rider Tom Pidcock's words) in order to combat the asphalt melting in the heat, with the unfortunate side-effect that it seems to be slippery and several riders (including Tom Pidcock) crashed going around a corner when the lost traction.

Coverage here: https://velo.outsideonline.com/road/road-racing/tour-de-fran...

But of course, this was done in response to past serious crashes that occured because the asphalt melted. So, it's sort of a damned if you do damned if you dont scenario for the organizers.

Pepe's Towing in Los Angeles reports asphalt collapses where loaded semitrailers are parked with the landing gear down. On hot days the concentrated load of the landing gear sometimes punches through the asphalt.[1]

This is why truck dock areas are usually paved with concrete.

[1] https://www.youtube.com/watch?v=LBrULmCGJfc

Motorcycle riders also report their sidestands sinking into asphalt on very hot days, to the extent that many of them carry some kind of wide weight-spreading thing to put under the stand. Apparently a face plate (?) for an electrical junction box works great.

Usually, a crushed soda can is good enough to prevent the kickstand to sync in the pavement. You can usually find a can in a random parking lot. That, or find a strip of concrete. That's why sometimes motorcycle park on the sidewalk in front of big box stores on a hot day.

Yep, I use a soda can and have never had any issues.

My bicycle did this as kid in the summer

Years ago Chicago started putting concrete pads on the road at bus stops because the busses stopping in the exact same spot repeatedly was carving ruts into the asphalt.

Yeah, my city is currently going through every bus stop in the city, redoing the pavement in concrete. Construction season has been nasty for us this year :p

A city I used to live in did the same thing when they refurbished all the major bus stops. I always wondered why

Also if a vehicle is stopped and the driver turns the wheel (with power steering this isn't hard) - it will eventually drill holes in asphalt - you can sometimes see this in house driveways where someone turns around.

You can even see the asphalt "waves" pushed by the buses stopping here over and over again

I've lived in Washington DC for 20 years and I never realized why the bus stops here are concrete! Thank you for this.

> But of course, this was done in response to past serious crashes that occurred because the asphalt melted. So, it's sort of a damned if you do damned if you don't scenario for the organizers.

Well, not entirely. You always have the option of repaving the roads with cobblestone or something.

Or just have the cyclists use fatter tyres.

That would also require fatter wheels. Which together have higher moment of inertia which makes for slower bikes (as more energy is required to get the wheels to the same speed).

Not exactly what people want in a race.

You can buy faster bikes than what is allowed at the Tour, so the only concern would be making records incomparable.

Fatter wheel is better than a dnf right?

Not really. If you finish second, you are the first to lose.

And yet fatter tyres are faster than the slimmer ones they used to run. No-one run slim tyres these days.

I could be wrong, but it turns out that somewhat fatter tires with lower pressure are faster because less energy is wasted by deforming slightly and rolling over small bumps, as opposed to thin high-pressure tire "bouncing" over pavement. There is less wasted vertical motion with the wider tires.

Cobblestones?

They're very slippery when dirty or wet. Seems like a much worse option.

This isn't a new thing in the Tour and it is normally not a problem, but since someone crashed on it then it must be the "white shit" that caused it. Not one of the hundreds of other variables - like the rider.

Paint is usually slippery. There are special standards for how slippery a paint painted on the tarmac can be. But it’s calculated for cars, not racing bicycles with teeny-weeny tires. Could have been easily the paint.

I mean, one of the first things they teach in motorcycle safety classes is that the road stripes are slippery and could cause a crash, especially in the rain. Even if there us a standard for how slippery it can be, it still doesn't match the traction of the road surface.

Perhaps they should have used some type of traction paint.

There are other problems with that in wet conditions.

Several riders independently crashed in the exact same spot, including Pidcock who is a famously good descender.

These are literally world class professionals at riding their bikes downhill around corners without crashing. If they say the white shit caused the roads to behave differently than they expected, I'm going to believe them.

...I know absolutely nothing about competitive cycling, but it occurs to me:

1. Would the Tour de France have been rescheduled if it was raining that day?

2. If the answer to #1 is no, is the paint any more slippery than water would have been?

3. If the answer to #1 is yes, then they should also reschedule for extreme heat.

1. No, they ride in the rain all the time.

2. It's not so much that the white shit (actually lime) is slippery, it's that it's unexpectedly slippery. Riders are generally quite good at going the right speed for the conditions. This just a new and unexpected condition they don't have experience with yet.

3. They did shorten one stage because of extreme heat, and there has been talk about rescheduling (both in terms of season, and moving the races into cooler parts fo the day), but the Tour is pretty tradition bound, so it'd take something quite exceptional to see that happen.

Practical Engineering already explained the correct solution to this problem:

https://youtu.be/zqmOSMAtadc?si=UUlmnk9sI-leq0SV

But of course, American infrastructure was built on the cheap, and is not maintained correctly. This is why we can't have nice things.

Why couldn't this also help with continuous-welded rail?

Your own video points out that it's still prone to trade-offs: rail breaks in the cold are better than buckling in the heat, but what if you could reduce the high point with white paint so you could expand the practical temperature range?

Or paint that turns black at low temp and white at higher temp?

This is what I want on my house and my car

We have like 220,000 miles of railroad. We do have nice things: a working freight railroad system that helps reduce transit costs.

If the freight rail system were as good as it should be, long distance trucking would be a rounding error instead of the dominant freight mode.

Trucks and trains serve different purposes. My understanding is the US has a higher percentage than most of freight carried by rail. Indeed at the expense of its passenger rail

Airlines killed passenger rail, not freight. Prior to it all being rolled into Amtrak virtually every railroad was losing money on passenger service.

The Post Office shifting mail transport from trains to planes is what changed the economics.

The passenger trains also carried mail, which helped make them profitable. Then the mail, and the money, moved to passenger planes.

Canada is moving away from moving regular mail by air to cut costs.

Dunno if it will move by train or truck.

Probably too late to add much volume on the ground.

Long distance trucking gets heavily subsidized by all other road users. Damage is caused by the fourth power of weight, but trucking only paid 35% of maintenance while being responsible for 99% of the cost.

https://truecostblog.com/2009/06/02/the-hidden-trucking-indu...

> American [rail] was built on the cheap, and is not maintained correctly

edit: I'm not sure anymore; I know most of the network is well maintained, but there could be large sections that are not, I'm not up to date on it.

It's certainly been doing better since the previous US administration put some cash in the infrastructure jar.

2025 Infrastructure Report Card | ASCE

  The 2025 grades range from a B in ports to a D in stormwater and transit. For the first time since 1998, no Report Card categories were rated D−. Among the 18 categories assessed, eight saw grade increases. 

~ https://infrastructurereportcard.org/

I dare say the next report card might not be so rosy.

Rail: B-

~ https://infrastructurereportcard.org/cat-item/rail-infrastru...

I love a simple solution to billion dollar problems

...that will be done for a few years, dwindling quality and measurement, lack of continuous data collection, or sparse, which loses 'track' of performance and effect. Then, lots of subcontractors will use the wrong paint (maybe a black market appears), incorrect application, too thick too thin on top instead of the sides... more derailments start occuring because the whole program gets used to boost stock price and try to get fed contracts instead of actually engineering a solution and maintaining it as protocol.

Lots of major industrial specialty paint manufacturers and white labelers are publicly traded, owned by BR & VG.

At least they're doing something.

I couldn't believe the state of US railtrack:

https://www.youtube.com/watch?v=9X2A2f6E5DI

Just go slower! We don't want to pay for maintenance. What's the worst that could happen? You derail and your toxic payload catches fire and poisons the neighbourhood?

https://en.wikipedia.org/wiki/East_Palestine,_Ohio,_train_de...

Maintenance is expensive, profits are now!

I hate that you are both correct.

A new mantra for Wall Street.

It's funny you mention that, since I mentally associate Union Pacific with the worst of US rail disinvestment. They're the ones that were patient zero for the "precision scheduled railroading" brainworm that led all our railroads to downgrade track and lengthen trains to insane lengths[1]. Or at the very least, they were at the top of Amtrak's delay-shaming list until a few years ago[0] when they somehow improved???

...anyway, I'm now genuinely wondering how the hell rail in such an awful state can still maintain the correct gauge for trains to run on!?

[0] https://www.amtrak.com/content/dam/projects/dotcom/english/p...

[1] Salt Lake City is trisected by Union Pacific freight rail. We have some of the largest city blocks in North America, but they're still not long enough to avoid a single stopped Union Pacific train blocking multiple crossings for hours on end. If you want to really, REALLY hate trains, move to the west side of SLC.

Also, talk to your politician about the Rio Grande Plan.

"That’s huge. If you’re not fighting the sun’s heat, you dramatically reduce the risk of the rail shifting.”

Am I misreading or does this say the opposite of what they meant?

I think the safety officer meant that white paint prevents the rail from heating up. The heating of rails contributes to problems with derailment. If the heat isn't a contributor, that heat is one less thing you have to fight (as in account for).

But the photo caption paraphrases him and says that the white paint fights (as in prevents) the heat, which uses similar words but a different logic to it (but the same overall meaning).

If I've got that right, then I think the blame lies on whoever wrote this article for making it confusing.

You are misreading. Basically the white paint is "fighting the sun's heat".

But that's backwards. I took it to mean the rails or the engineers are no longer fighting (coping with) heat input from the sun because the rail never receives that heat when it's reflected away by the paint.

It means the paint is fighting the energy conversion potential encroaching on the steel, in place of the steel fighting it with no covering or shield

I know what it means. "you're not fighting the sun's heat" means "the paint is fighting the sun's heat" but that's no explanation of how it could mean that. I say it's backwards because clearly whatever's doing the fighting is not the paint because it has the opposite effect. It must be the steel, as you say, or the people struggling with the problem.

Fighting like a verb I think

Reflecting the sun means the rail no longer has to fight the sun's heat.

Without the paint, the sun heats the rail and heat expansion fights against the elements holding the rail in place until the rail cools down or something moves. If the something moves, trains can derail.

Paint everything white! Why stop at rails?

Mostly because it doesn't stay white and looks bad. But it doesn't stop people from painting their siding white, for example.

Why paint the sides of the rails? Well you can paint the tops, but it tends to gum up the wheels and get worn off.

You want a paint with high reflectivity and high emissivity. Just be sure you aren't using infrared light temp measurement as to measure and make claims about differences in temperature, emissivity is something to watch out for when measuring temperature in that way.

20 degrees is surprising, I sure wish my car was white in the summer.

I wonder if you have okay effects with white rails in the winter?

> Why paint the sides of the rails? Well you can paint the tops, but it tends to gum up the wheels and get worn off.

Tops of rails are already pretty shiny for any mainline track seeing a couple dozen trains a day. I'd bet they are more reflective than white paint could be. And the paint would be gone after the first train passes through anyways.

They rust pretty quick, but with regular use it doesn't build up much since it's constantly being worn off from the wheel friction.

Thank you, I was wondering why the need for paint rather than side polishing and the added knowledge that this blend of Steel rusts would ruin that for the non-contact surfaces.

Painting it cheeper than polishing. But I wanted to know the reason they needed to / that made it so.

The top of the rail is already white!!!

It's just polished, so that it is reflective.

If you sanded it with your 180 grit paper, you would get the scattering which appears white.

I recall a test initiative was done some time ago for painting (or mixing in, I forget) roads teal. It improved the heat island where it was placed, and wasn't too bright for motorists. I wonder why that never went anywhere...

this isn’t the point of the story, but is that paint truck driving on the railroad tracks?

Yes, they're called "high-rail" or "road-rail" vehicles. They have rail wheels that can be lowered down to drive on tracks or raised up for road use.

And sometimes the axel is short (narrow), so the tires are on the rail. It's funny to see them on a standard road.

They just use custom rims.

> Union Pacific Is Tackling Rail Heat to Keep America’s Freight on Track

Someone talked to an LLM which convinced them they had a brilliant idea.

Just a guess ...

You can literally buy derailers[1]. People will find away around this, making white paint useless. Engineers need to engineer.

1. https://www.aldonco.com/product-category/derails/

   Do NOT use where speeds exceed 5 m.p.h.

Not sure what you're thinking of, but these widgets you linked won't solve the problem of long rail sections heating up in the sun, buckling, and derailing freight trains travelling at normal speeds.

OK, but a heatwave isn't going to buy a derailer

this is tackling regular natural derailment incidents not terrorism

Derailers are common and are placed where people are working on tracks so a runaway car will go off the tracks instead of hitting the workers.

Why worry about memory safety? Users can literally "kill -9" anyway.

- maybe consider electrifying the entire freight network of the USA like some of the other countries have done (mind you very large countries)

- then you might not have to worry increasing heat levels that much

Why would electrification prevent track from warping due to heat from the sun?

cuts down carbon footpriunt which in the long run ll help cut down temperatures

There's a lot more low hanging fruit with higher payoff than optimizing all rail in the USA.

Also, a guess, but I think you might benefit from checking out the actual size of countries vs the Mercator projection size of countries.

If we are in the long run stabilising that would be already a win. Until the temperatures go down it will be a long, long, long time if ever. So temperatures will go up and we have to adjust. The scale of required adjustments is not understood yet and the increasing number of surprising needs to adjust is scary.

If we get to a point where direct sunshine all afternoon isn't hot, we're going to be in a big block of ice.

there’s a genius here, the crème de la crème of today’s thinkers

> “When people first saw it, they said, ‘Why haven’t we been doing this for a hundred years?’” Doerr said. “That’s the kind of question I love to hear, because it means the culture of safety innovation is alive and well.”

Union Pacific haven’t been doing this precisely because they don’t have a culture of innovation…

The question applies more broadly than Union Pacific. Why hasn't this been an industry standard for 100 years?

> Why hasn't this been an industry standard for 100 years?

Because the US heavy rail system is a duopoly with no incentive to innovate.

This of course beeing the effect of seemlessly welded together rail with nowhere to go..

Indeed. Didn't they used to have expansion gaps?

They did. It's what caused the click-clack sound trains used to have, and the change to continuous welded rail is why there is no click-clack anymore.

I'm surprised that this is as effective as the numbers suggest. I would have thought steel rails would be pretty good at reflecting/radiating heat. TIL.

Reflecting and radiating heat are mutually exclusive, and if some material is good at radiating heat, it is also good at absorbing heat, otherwise it would violate the laws of thermodynamics.

It is a bit more complicated than that because light come in different wavelength, but it is the general idea.

Railroad rails tend to be dark except for the polished top surface, so they absorb/radiate the heat more than they reflect it. Painting them white changes that, it makes them less effective at radiating their own heat, but because they don't produce much heat by themselves, it is not a big effect, but it also makes them less effective at absorbing the heat from the sun, a much greater effect, so, the rails get cooler overall.

Hopefully they have a sandblaster mounted to the same train to clean the rails first, else they're gonna have to do this again every year...

Or they have a heavy rust converter (phosphoric acid?) built into it. Similar to a self-etching primer.

20 degree drop. That’s crazy

Italy has been doing this for decades.[citation needed]

According to the Dutch railway maintainer, it's not needed there, and the effect is not really proven: https://www.prorail.nl/veelgestelde-vragen/zomer/waarom-zijn...

Same for the Swiss, according to the natioanl railway company the results of their tests were “inconclusive”, but other operators of the Swiss network say that it depends on the exposure and other factors (but the challenge is keeping them clean, in a week they are already too dirty). https://www.rsi.ch/info/svizzera/I-binari-sbiancati-non-serv...

Sorry, but both Switserland and definitly the Netherlands are further North vs a significant percentage of the USA.

Bern, Switzerland is very close to the same latitude as Quebec City, CA or Fargo, ND, USA.

The Netherlands is even further North. Due to the lower angle of the sun hitting them they might get completely different results vs here in the South-Western USA.

Also weird in the article:

> Het aanbrengen is behoorlijk arbeidsintensief.

Really? How is driving a machine over the rail labor-intensive?

Because there is a lot of rail. And it requires inspection.