Trains run on big metal rails made out of steel. These rails are simple, tough, and fit for purpose. With no surface treatment, they stand up to the elements and the punishment from hundreds of trains passing by every day. They’ve changed little in recent decades. But then certain railways decided to start painting their tracks – and not just to be fashionable. Let’s examine why.
Today’s railways face a new challenge: excessive heat. As the global warming narrative finally makes good on its dreadful promise, daily temperatures are hitting exceptional highs in some areas. These temperatures often exceed what were once considered reasonable design limits for conventional railways.
The result? The rails expand too far on hot days, and all hell breaks loose. The British call it “buckling.” The Americans, inexplicably, call it “sun kink.” No matter what it’s called, the solution to this problem might be exceptionally simple: white paint.
We've certainly been feeling the heat– but we're not the only ones.
Did you know extreme heat can also affect train tracks?
Check out our blog to learn how: https://t.co/OzsJIAYrjL pic.twitter.com/0FXh7N4wPz
— CapMetro (@CapMetroATX) August 17, 2023
Paint It White
Hot summer days are becoming too much for infrastructure around the globe. Whether you’re dealing with a bridge in New York or a railway in Britain, the root cause of your problems is likely the same: Heat makes metal expand. Engineers account for this when designing infrastructure, but they can only do so much. Eventually, if things get too hot, they expand too far, and you get problems.
As rails grow longer in the heat, they tend to buckle, typically pushing out laterally and breaking free of their sleepers or ties. This can be a great danger, as buckled rails no longer maintain the correct orientation, support, or separation distance to support passing trains. Derailments are common on buckled track if the problem isn’t identified before a train reaches the deformed rails.
Modern railways use continuously welded steel rails, where each length of rail is welded onto the previous one to create a continuous run. In extreme cold, the steel rails may contract so much that they snap, and in extreme heat, they may expand so far that they buckle or kink.
asdf
The temperature range a railway can operate in is set during the construction process through a process called “rail stressing.” The track is installed in a stressed state, such that at a given “stress-free temperature” (SFT) there is no tension or compression caused by thermal effects. In the United Kingdom, for example, rail is typically installed so that it sits in an unstressed state at 80.6 °F (27 °C), the mean temperature in summer. In the US, rail is usually set for a stress-free temperature of 95 to 109 °F.
However, exceed this temperature by too much, and the rail may buckle. With an SFT of 80.6 °F, much of the British rail network is safe up to a track temperature of 114 °F (46 °C) before it buckles. This corresponds with an ambient temperature of around 86 °F (30 °C). However, as ambient temperatures continue to rise, rails are at times exceeding 123 °F (51 °C). The hotter the temperature, the more likely the rails will buckle.
Numerous mitigation methods exist to avoid buckling. On hotter days, railways may choose to run trains more slowly, in an effort to reduce forces on the rails and lessen any destabilizing disturbances. Services may be canceled entirely to avoid the risk of derailment.
Rails can also be installed with higher stress-free temperatures, allowing them to withstand hotter conditions. However, this makes them more susceptible to fractures in cooler temperatures. This is often unacceptable for areas with cooler climates.
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????️ If we stressed our rails for exceptionally hot weather, they wouldn’t be safe for the winter and we’d have broken rail because it’s too cold. ❄️???? That’s why other countries choose different temperature ranges depending on their climate. pic.twitter.com/VVCLbPT5NB
— Network Rail (@networkrail) July 19, 2022
Cooling the rails is becoming an altogether more popular solution, however. It’s remarkably simple to achieve, too. Simply by covering the rails with white paint, their temperature can be reduced by anywhere from 9-18 °F. In many cases, this is enough to bring the rails back down to a reasonable temperature where buckling isn’t an issue.
Only the sides of the rails are painted. There’d be no value in painting the top, as paint would quickly wear away under the weight of a locomotive. Besides, the shiny top surface is relatively reflective already.
Spotted white rails while looking our your train window? We paint these so they absorb less heat – and expand less. Typically, a rail painted white is 5°C to 10°C cooler than one left unpainted. pic.twitter.com/KRs7Zndkmm
— Network Rail Scotland (@NetworkRailSCOT) July 16, 2022
The mechanism behind this is simple. The dark surface of a railway track will absorb a great deal of heat energy from the sun. Cover the track in white paint, however, and a great deal of that solar energy will instead be reflected rather than absorbed. Having absorbed less energy from the sun, the track will remain cooler. The same technique works for buildings, too, and has been considered a useful technique to help keep homes cooler.
Paint can be applied simply by hand, or with specialist equipment. In Britain, rail workers are stuck trudging along with brush and bucket. Indian railways appear to have developed push carts to do the job more easily. Italian railways use dedicated service vehicles to spray the rails. In certain areas, the paint is applied each summer to keep temperatures in check.
Brits paint by hand.
Indian crews use push carts to spray the rails.
Italian operators have a spray vehicle built especially for this purpose.
Painting the rails might seem odd at first glance. Under normal circumstances, it would seem like a fool’s errand. “Go and paint the rails to keep the sun off!” you’d tell the apprentice. And yet, white paint is instead proving a crucial tool for railways to keep their operations running under hotter summer temperatures. It’s a strange world we live in, but as it changes, we’ll find ourselves turning to strange solutions like these more often than you might think.
Image credits: Network Rail, Network Rail via Facebook screenshot, Ferrovie.info via YouTube, US DOT
That Italian video seems like they are over spraying onto the ground and wasting a lot of paint. After watching them paint the stripes on the road in front of my house, I would expect that with some more modern tech they could paint just the rail and maybe spikes and plates, if needed. Oh, maybe throw some AI at it.
Anyone tell snow piercer about steel stress in cold yet?
Scientists/Engineers: Painting the train tracks on the sides will significantly reduce track temperature and related buckling. Would you like us to design a rail cart to be able to quickly paint all the tracks in the network?
UK: Best we can do is give a guy a mop and bucket of paint.
Sad that the Brits haven’t discovered spray painting yet. Here in the US we have pickup trucks with undercarriage add-ons that let them run on the rails. It would be easy to have a big tank of paint in the truck bed and some nozzles similar to what they use for painting lines on the roadways.
Sounds like a job for Banksy
Once again; just because the British invented trains, it doesn’t mean that we’re any good at them.
I found a good explanation of this phenomenon on reddit
https://www.reddit.com/r/askscience/comments/w2wgez/how_do_train_tracks_withstand_hot_and_cold/
Suddenly all the homophobes are rushing out to slather themselves in white body paint to make sure they stay straight!
Ermm. Huh?
How does this dumb-dumb-remark get two likes? Honestly. I came back here after dinner just to see what was up, and…yeah. Some of you folks have way worse problems than me.
We get it, you don’t have a sense of humor. It was only intended to offend homophobes btw.
Not a chance I’m going to engage into an interweb spat with a random on what I consider a friend’s site, more than this reply.
What I will say before I totally disengage from this convo is that if you are “intending to offend” anyone…you can fuck right off to whatever, wherever you think that that type of shit is cool.
Just read what you just wrote. You intentionally tried to be a dick. Like, you actually tried? To prove what? It’s fucking insane to think, “Yeah, I’m going to insult people today with the most generically inoffensive, offensive dig. That should be fulfilling. It will actually mean nothing other than a word salad of things I have absorbed lately. What the point of it all is irrelevant. I just feel like insulting someone. Somehow. Let’s keep hate alive on a post about painting train rails.”
I’m not going to ask you to explain yourself, because that would require further discourse.
With all due respect. You, sir, are a fucking moron.
Not cool.
“With all due respect, you Sir are a fucking moron”…
That’s not how that works. But seriously, why are you so pissed off? Are you a homophobe or just feel like you need to defend that poor oppressed segment of society? Maybe you don’t know what ‘homophobe’ means? I really truly want to understand.
Whoa, what could possibly trigger someone this much in a joke making fun of homophobes? What made you comment once, come back, comment again passing judgment on the couple people who liked the joke, and force engagement to say that you won’t be engaging, ending four paragraphs about how bad it is to insult people with an ad hominem insult?
I hope you get a chance to re-read this whole interaction and understand who’s actually being insultuous here.
It was only meant to offend homophobes
He must be having a bad day. So it was a bad joke. Whoop de doooo.
Let’s be petty and childish. HahI I got FIVE likes!
That’s not paint!!
Is that in the southern US? In the north we rarely hit 95, never mind as an average. Plus, our winter temperatures would result in something like a 110 degree drop from the stress-free temperature, which seems…bad. I would expect northern rails to be something closer to the UK temp.
Keep in mind that this is the temperature of the rail, not the air.
Ah, that does seem more plausible.
In Maine yesterday I got in my car and it read 99 on the outside temp gauge. The official temp for the day was 88, but it was hot out there on the asphalt. Radiant heat does make a difference.
That Indian video has very concise, simple narration paired with some of the most epilepsy inducing editing I’ve seen.
I wonder if the Brits are sticking with manual labor to keep the tracks open while they’re being painted.
You mean ‘labour’…
You ‘avin a laugh?
I knew just from the header pic that you wouldn’t be citing the MTA in this piece. Not to shit on my union brothers, but 4 dudes all working at the same time? That’s like spotting the real Bigfoot.
Anyway, yeah. Putting temporary speed restrictions on certain sections of track is quite common in all seasons due to temperature (among many other reasons), as it has been for 150 years.
Painting the rails is a nice idea, and I’m glad it helps a little. But, there are only so many ways to mitigate the materials. As long as we are dealing with steel…we are gonna deal with steel. Every day is a new day for it to fuck up.
Quite similar to the experiments with painted or lighter colored pavement, to try to reduce urban heat islands
The thing about pavement is that it regresses to the mean. Asphalt starts out black, concrete starts out white. Within a few years, they’re both gray.
Without reading: because they reflect more heat and won’t warp when they’re not absorbing everything dark steel will.
After reading: hmm yes, smug know-it-all levels are appropriately high.
It does seem like this would be extremely easy to automate. I mean shit, a road is harder to paint correctly (and if the lines near me are any indication, it very much shows). A rail line has two fixed tracks a fixed distance apart. Send a painting cart down the track, top off the paint hopper every once in a while, and validate with pretty much any visible or IR light source for reflectivity. Intervene with a human at missed spots and junctions as appropriate.
At least in the US, you are still gonna need at least one Conductor, a Switcher, and an Engineer. No matter what. If it’s on the rails, there needs to be some heartbeats on board.
There are certain track cars that can run with just one person, but those are typically just actual pick up trucks with modded wheels. Anything larger needs what I describe above.
That doesn’t offend my sensibilities. A human or two in the loop is a valuable thing, especially when a failure mode includes uncontrolled railway cars (carts? tooling? what’s the word for something less than a car or engine, but not either of those things?).
Typically, they are referred to as work equipment/track equipment. Depends on what it is, though. Some get technical names, like ballast car/rail scrubber etc., others get “less gentlemanly” names, or joke names. For instance, on the MTA commuter rails, the rail scrubbers are actually a consist of two work engines, the actual “power washer” piece, a water tank car, and sometimes something else attached (for whatever reason). That consist (actually, there are up to three running in the fall) is called “Water World”.
As an aside, a “runaway” piece is very rare. Very rare. A whole bunch of shit has to go wrong at the same time, usually with ALL self-correcting mechanisms that work against each other, all failing at once. You’d almost have to really try to create such a scenario on purpose, for that to happen.
It seems to me that the way to do this would be with one of the rail trucks.
Get or make something like this, https://www.vezosusa.com/vezos-products/view-all-products/line-striping-machines/truck-mounted-stripers/roadmaster-2-5-line-striping-pickup-truck-detail.html Of course it would need a different spray head system to do both sides of both rails. Then when summer is over pull it out and put it in storage for the winter and use the truck for other purposes.
Technically, that would be “theoretically” possible. lol.
I could write 30 paragraphs about it, but let’s keep it simple. You’re gonna need a dude to inspect the paint. You’re gonna need a dude to make sure the filler is level. You’re gonna need a dude to ensure the bolts are aligned. You’re gonna need a Track Supervisor to sign off on the installation and “road worthiness”. You’re gonna need a Track Driver that not only will sign off on the fact that the rig is “certified”, but also willing to take the blame if it fails, especially if it derails en-route. You are gonna need more than what I’ve already mentioned. This is for brevity, lol.
You are also gonna need a “driver” and/or/ copilot that is certified on the territory (FRA rules, btw) that recognizes the various CP’s and interlocking that they must cover and receive permission to move from the RTC. This equipment doesn’t receive standard Cab Signals, or shunting signals. It’s all manual. Not to even start on if the paint sprayer works…
Those certifications cost money. And time. In fact, a shitload. Not only is this for “Safety”, but a C.Y.A. for the railroad in case of a lawsuit. Also, add into the scenario that what a Track Worker is doing, is operating equipment on the “Right-Of-Way” that an Engineer is already qualified on, and the track guy is doing it for less money.
This is where big problems emerge. Add onto the fact that a track guy has nowhere near the capability to deal with deaths/suicides that are certain to happen. Even at an M.A.S. of 30mph, at best case.
The easier solution is to create a “job” for a E, C, and A/C to run the equipment, bearing almost all of the liability, while a Track guy smokes a cigar out the window with only a thumbs up to proceed.
In summary, it’s cheaper to “create a job” that amounts to $5k a week to a certified train crew, rather than train some track guys to run independently and risk a million on a lawsuit (for a million different reasons).
The railroad is way more complicated than those outside of it realize. It’s a whole other universe, where complexity is the point, in order to protect century old jobs.
For the record, I LOVED being a Conductor. It’s an awesome career. It requires a lot more than most people are willing to give up. Hence, the higher than normal death rate/suicide rate of the crews themselves after seeing a dozen or so “splatz” in their career. It’s intense having a Billion dollars of liability on your shoulders every day.
Deadly dangerous, but also thrilling…in the dullest of repetitive ways. I don’t know of an applicable comparison. Maybe a fighter pilot? I dunno, but it’s close.
Deadly dangerous, but also thrilling…in the dullest of repetitive ways. My Bonus Son was a Conductor for a few years and the dullness was what pushed him out of that career. So yeah I do know more than the average bear about the rail system, but of course not that much.
Also to be clear I was just saying the simplest piece of equipment that would do the job in an automated manner and didn’t imply that it would make it a 1 person job. Even if it ended up “needing” a 4 person crew they would still get way more miles done per hour that 4 guys with mops. Heck just give the guys a sprayer with a guide instead of a damn mop.
I appreciate the reply! I was kinda epilepsy venting, lol.
In no way am I disagreeing that there is a more efficient way to go about any of it. There sure as shit is. But, it ain’t happening in this lifetime. There are ways that the corporate world works, the private sector works, the service sector works, etc., and then there is the Railroad. lol.
As far as your son goes, that’s a shame as at the same time I am proud of him. It takes a looooong time to see the benefits of it all. So, if it wasn’t his bag, I totally get it.
Train crews are a weird fucking bunch.
I’d be wiling to bet your son can attest to that,
He went into the Air Force (one of it not the oldest in his group for BMT), became a Crew Chief and got his A&P license. Now that he is out he is working in that industry and making good money. His old boss did contact him several times while he was still in the service and told him that he did have a job as soon as he was out. He did consider it for about 2 sec while he was still looking for his current position.
Whoa. Awesome. Good stuff!
I currently work with a 20 yr old. She acts that way in many respects, lol. The thing is, it turns out her whole goal in life was to be in the Air Force as a fighter pilot. She got denied for whatever reason, but is now training to fly private and is doing solo landings at unmanned airports lately as part of her training. I’d probably never tell her straight out how impressed I am about that, just because of circumstances, but I am. Basically, what I am saying is that what your son is doing rocks, and if it were me (not saying you don’t), I’d tell him that all the time.
I find it so impressive when a kid finds their passion and runs with it, and actually is good at it.
Congrats!
I mean, yeah, the Italian video in the bottom of the piece demonstrates just that. Quite easy to build a railcar to do it
Yeah, except now we can all tell when they haven’t cleaned the rails in ages.
Rails don’t typically need cleaning. They get plenty of moisture and friction naturally. The one exception is during “slip-slide” season, when there are work trains that go out and basically power wash all the leaves/oil residue every night.
It’s a sweet gig to get as a Conductor. It absolutely eats ass for the Engineer.
So in the future is there no way to automate this painting process when they come from the plant? Or is that just not worth it?
They might be able to use an enamel for the factory coat, but it still wouldn’t last the life of the rail.
More specifically, it’d only last the length of the service contract, and not a day more.
Because, that’s how it works. (In NY, anyway.)
If you wanna go into a depressing hole, look up the concrete ties replacement contract, where all the pieces were defective and had to be done twice in a year. Paid for twice in a year with no penalty to the “supplier”. That’s what the 11% tax in Yonkers gets ya. lol
Looking at the application of the thick white paint, I’m pretty sure they got a bunch of landlords to do those rails.