Trains May Soon Come Equipped With Debris-Zapping Lasers 194
Molly McHugh writes: Holland's chief transportation service is testing a unique new way to clear the rails of fallen leaves and other small debris: by mounting lasers on the fronts of locomotives. The lasers will cause the leaves, which produce a condition commonly referred to as "slippery rail" in the fall and winter months, to vanish in a puff of smoke.
They're leaves. (Score:3, Interesting)
Re:They're leaves. (Score:5, Insightful)
Re:They're leaves. (Score:4, Insightful)
gee I hope the third rail contacts on the electrical train I road to work don't hear you
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you're wrong about that, try the filters in the HVAC system.
Point is even a component that scrapes rail under brutal arcing conditions can last, so brush system would be non-issue
Re:They're leaves. (Score:5, Informative)
My point not shot down at all, shoes are replaced every 50,000km in the cars in my city. Brush of proper material could have huge life, wear not a barrier to use. In fact, they do put in "scrapers" next to the pickup shoes in the winter months for ice and snow. Is any of this getting through to you? can you connect the dots?
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Trains have been around for several centuries. If there was a trivial solution to remove leaves from the track, it would have been implemented 100+ years ago.
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You mean like Railhead Treatment Trains (RHTT) with various attachments and devices such as high power water jets, anti-freeze sprayers, ice/snow scrapers, traction gravel laying?
Yeah, existed long before you were born and in use now. They work fine, and without lasers.
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They work fine, and without lasers.
Eh, okay, maybe they're adequate, but they have the huge disadvantage you noted: no lasers!
Technology adaptation (Score:5, Informative)
About a decade ago the Brits had a slew of leaves-on-the tracks failure-to-brake accidents. Why now? everyone thought. In a bunch of places the embankments had been designed for coal-burning trains, which spit sparks, so the embankments were gravelled or very sparsely grassed. What trees the fires didn't suppress were cut down as seedlings every few years.
Time passes, the engines change fuel, someone notices they're spending money on maintaining the gravel and stops.
*Decades* pass and there are beautiful trees on the embankments tall enough to shed onto the tracks -- *that's* when the accidents start.
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1) Bag clip
2) slap-chop
3) Floating arm trebuchet
Re: They're leaves. (Score:4, Insightful)
What forces does the train put on them, exactly? Draw me a diagram.
If we followed your dumbass thinking we wouldn't have street sweepers, tires, or shoes.
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yes gravity shoe is consumable, every 50,000km on the four-shoe cars my city uses. Brushes would have much less brutal a life than those things
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gee I hope the third rail contacts on the electrical train I road to work don't hear you
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Well, those contacts do wear down and require require regular maintenance as do the rails themselves. That such maintenance was done is the reason you were able to get to work.
Road or rode? (Score:2)
gee I hope the third rail contacts on the electrical train I road to work don't hear you
If you 'road' your train then wearing down your third rail is not really an issue...the screaming pedestrians and motorists trying to get our of your way might be a bigger problem though.
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If a smooth contact could clear the rails the breaking wheels would do it. Rotating bristles will wear an awful lot faster.
You'd need something akin to an assembly of hedge trimmers, so you can just keep spooling thread.
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Oops, I meant lawn trimmer.
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For high speed rail they use pantographs. They have to stagger them to keep wear even over their width.
Brushes are not suited to high speed rail because they are either ineffective or create too much drag at high speeds.
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anything that directly touches the track
High pressure air then. Got to be less harmful to the steel than a wet leaf vaporizing laser.
A couple thousand PSIG will take off the wet leaves, water, ice, light rust, paint and anything else they could possibly care about.
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High pressure air then.
If the air nozzle is close to the track, it will be hit by debris, and need frequent repairs. If it is located farther above the track, the air stream will dissipate.
Got to be less harmful to the steel than a wet leaf vaporizing laser.
The laser does not turn on continuously while the leaf vaporizes. It fires a very short burst, delivering all the energy to the leaf. Then it stops, while the leaf is hot enough to vaporize, but has not yet done so. The surface of the rail should not be ablated at all.
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This won't happen, due to the fire hazard it presents.
In Holland? In the winter months? I don't think so. Everything is cold and damp. There is rain and drizzle almost every day. The ground oozes water into your footprints.
Even if it does start a brush fire, they can put it out it by opening a dike.
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The solution is pretty simple. Basically a train is not just one set of wheels but many sets of wheels and basically not every wheel on the train needs to function in exactly the same manner. So the rear wheels can provide most of the breaking, middles sets support and the front sets specifically designed to displace materials on the track. They do not need to be under full load but only under partial sprung load, with there surface designed to break up materials and push them off to one side. There is a h
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It will also shoot out car windshields with pebbles and other loose objects. High-pressure air is a serious industrial safety concern.
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And high powered lasers aren't?
Re:They're leaves. (Score:5, Funny)
At least those are pointed down at the track; the reflections aren't much of a hazard. But yes, if the train rolls over you, you may incur eye damage.
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At least those are pointed down at the track; the reflections aren't much of a hazard.
Lasers strong enough to set things on fire quickly tend to also be strong enough to cause eye damage from diffuse reflection, especially when you are trying to burn something larger than a pin point and that is possibly quite damp.
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High pressure air then
FT2ndArticle: "We have a fleet of rail-head treatment trains which clean the rails using water jets and then apply a sand-based gel to help trains gain adhesion."
Another page says there are 55 treatment trains. There are something like 4000 "trains", so maybe the point of this system is it can be attached to normal trains, rather than requiring a special train.
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Wouldn't it be easier to mount brushes or something?
Maybe, but not nearly 1/20th as cool as lasers. Please turn in your nerd card at the door.
Re:They're leaves. (Score:4, Insightful)
Exercise for the reader: Try sweeping the leaves off of your driveway or sidewalk when they are wet and stuck to the pavement. Now imaging accomplishing that in a single high-speed sweep.
IANATE but I believe many trains already have such a brush but even if they don't they are not effective.
Freaking laser beams have a bunch of other issues but are WAY cooler ;-)
Re:They're leaves. (Score:5, Funny)
Indeed. Where are they going to attach the sharks?
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My first thought too. One way would include a special fish-tank car being pushed in front of the locomotive...
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It's not Pirate Day, buddy.
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Pushing the turbo button for a brush won't clear away jumpers or renegade livestock standing on the rail.
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*pew!* *pew!* *pew!* *splat*
I'm not convinced pre-cooking the jumper is going to reduce the cleanup very much.
Re:They're leaves. (Score:5, Informative)
They're not "just leaves".
I thought this looked familiar, and sure enough, google turned up this article from 2007 [railway-technology.com] about the system and the guy who spent eight years and 5 million GBP to try to solve it.
"Every time a train runs over a pile of leaves, they are squashed into a hard, black, shiny, Teflon-like substance that makes it more difficult for trains to slow down and stop."
"Rofin-Sinar created a monster. The final version of the laser railhead cleaner contains two lasers capable of producing 2kW each. The pulsed energy is channelled via a fibre optic, which delivers a round beam in a straight line across the rail.
The pulsed beam hits the rail 25,000 times per second. The leafy mulch absorbs each 5,000C pulse of light, causing it to heat rapidly, expand and lift off the rails. Tests have found that the laser cleaner also works on oil, grease, ice and other problematic substances."
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In games you pulse lasers because the laser is blocked and scattered by whatever you're vaporizing with it. I don't know anything useful, but that's my guess anyway :p
OK, OK, I will google, since you forgot how. You must be taking the wrong drugs, eh? http://en.wikipedia.org/wiki/L... [wikipedia.org]
(TL;DR: both what I said — battletech FTW — and also the technique is used to reduce heat while cutting. The goal is not to heat the rail...)
Even if their wet? (Score:4, Insightful)
Re:Even if their wet? (Score:5, Insightful)
1) They're*
2) Dear God, people, attaching lasers to anything makes it epic cool. What the hell has happened to Slashdot?
Re:Even if their wet? (Score:4, Funny)
We need to test all the competing technologies for this to pick the best:
1) high power lasers.
2). Flame throwers
3). High power plasma discharges.
4). rocket-propelled Anti-leaf attack drones
5). Jets of ClF3
6) Anti-proton beams.
7). Brushes
8) US only: a guy walking ahead of the train with a broom.
then we can see which is the most cost effective and safe - and get some cool youtube videos as well.
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Young/New generation, perhaps?
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I would think that any laser reflective off a metal rail would lose focus and be scatter far too much to burn a hole in anything. This is a gut feel though and not based on hard math.
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The rail will be well polished due to trains running over it. Because laser beams are coherent and well columnated to begin with, they will not likely diffuse nearly enough to make incidental exposure safe for humans.
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In other words, the rails will not diffuse the light sufficiently to render the reflected beam safe, just sufficiently to make incidental contact inevitable.
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We may be reading past each other. I agree that the various reflected laser light will be harmful to human beings. The rail is sufficiently polished to reflect strongly yet sufficiently uneven that the reflected light will have a significant chance of hitting an unfortunate someone. Unlike a regular strong light that would scatter to the point of being harmless.
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I had the same concern with the mosquito-zapping lasers, which IIRC are only around 40W (which is still a LOT). It's a really cool idea until someone throws an aluminum can in my yard and a reflected laser hits someone in the eye. I'd think the power required to burn leaves off would be a lot higher than the power required to warm up mosquitoes enough to kill them.
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Could it also distort the rail itself? Probably not from one train passing over it, but once a few hundred trains zap the rails, it might distort just enough to cause problems.
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The real question is, of course, "Where did they find room to put the shark tank?"
Umm... (Score:3)
My understanding is that some trains even have a compressed air supply already(for pneumatic braking and sundry other duties), and all trains, since they have to move, are going to have a fairly burly supply of either mechanical or electrical energy to run a compressor. Much simpler and likely more durable than a laser and optics high-powered enough for debris clearing, and less likely to cause amusing track fires.
Am I missing something here, or did somebody just fail to KISS?
Re:Umm... (Score:4, Insightful)
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I think the concern isn't dry leaves so much as wet ones that are plastered to the rail like decals on a middle school girl's notebook.
An air jet reasonably close to the rail will blow stuff like that off in a tiny fraction of a second. Air's really good at that sort of thing, it blows the water out and then it can pick up the item, and it happens surprisingly fast. Too fast to see, kind of fast. What it won't blow off, though, is a leaf that partially decomposed and then glued itself to the rail. That ain't coming off of there. Burning it off with a laser probably would work OK, but it would also be more dangerous than an air jet. Both ar
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Maybe I'm just a terrible person whose sense of childlike wonder and love of lasers has shriveled; but isn't 'clearing leaves' the sort of job where a simple nozzle blowing compressed air(turned on and off based on sensor input if it turns out that you can implement a sensor system at lower cost than just running the compressor a bit more often) at the track immediately in front of the wheels would be more than adequate for the purpose?
You're missing the damage that compressed air / water does to the substrate of the track. It undermines the foundations of the line. They already do this, but it costs them more money to repair the line than it would if the leaves were just burnt on the spot.
Fire (Score:2, Insightful)
Wait.. "puff of smoke" ? If the lasers are powerful enough to do that, what's keeping it from setting things on fire?
Re:Fire (Score:5, Insightful)
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Not to mention that a speeding train tends to cause a wind gust. You could get a leaf slight burning by the laser, tossed around by the train's wind currents, and land in a bush or grassy area a few feet away. Drought + Laser Train = Trail of Fire.
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Why would they be using something that deals with "Wet" leaves in a drought?
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Calibration (Score:2, Insightful)
Seems like it would take some careful calibration to make a laser that would burn off wet leaves plastered to the rail and yet not soften the hardened steel of the rail that's going to have a multi-ton train passing over it in seconds.
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Seems like it would take some careful calibration to make a laser that would burn off wet leaves plastered to the rail and yet not soften the hardened steel of the rail that's going to have a multi-ton train passing over it in seconds.
If you RTFA, they use a laser wavelength that reflects off the steel instead of being absorbed.
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RTFA? This is /. Why would I break tradition and do that?
Re:Calibration (Score:5, Informative)
Leaves burn well below the annealing temperature of most steels.
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I think the thermal inertia of a big metallic rail must be, say,10000 times the one of a tree leaf.
Or maybe 100 000 ?
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Seems like it would take some careful calibration to make a laser that would burn off wet leaves plastered to the rail and yet not soften the hardened steel of the rail that's going to have a multi-ton train passing over it in seconds.
If I were doing this -- and I'm not claiming it's feasible, but let's call this a gedankenexperiment -- I'd use a system set up to ablate [wikipedia.org] the material, which Wikipedia says so I don't have to: "Very short laser pulses remove material so quickly that the surrounding material absorbs very little heat, so laser drilling can be done on delicate or heat-sensitive materials," and " laser energy can be selectively absorbed by coatings, particularly on metal, so CO2 or Nd:YAG pulsed lasers can be used to clean surf
Re:Calibration (Score:5, Informative)
Sorry to reply to myself but since Wikipedia doesn't actually bother to talk about mechanisms, I will. You can remove a surface with a laser through heating, which applies enough photons to the surface atoms that they vibrate loose, which is a slow process that transmits piles of heat downwards. Or you can use a laser whose wavelength is shorter than the strength of the sigma electron bonds in the material, in which case the electrons absorb the photons, get popped into a higher orbital, and the bond that held the two atoms together simply isn't there anymore and the now free atoms can just drift away. There is in theory no heat generated at all. In practice there are so many photons coming in all at once that there's a metric buttload of photons being absorbed by everything, so what actually happens is the wavefront hits and turns the first couple of atomic layers into a plasma, that erupts away from the surface and leaves the underlying surface close to untouched. So that's the mechanistic difference between burning and ablation: photon flux and wavelength.
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Ablation can in theory remove single atomic layers with thermal damage only a few atoms deep to the underlying surface.
So the damage to the surface is only a few times larger than what was removed?
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Ablation can in theory remove single atomic layers with thermal damage only a few atoms deep to the underlying surface.
So the damage to the surface is only a few times larger than what was removed?
The damage is only a few atomic layers deep, more or less independent of how much material is removed.
A large limitation to how much you can remove is that you build this huge largely opaque cloud of debris blasting off the surface of the material so you can't get new photons into the surface anymore, but you can peel stuff off a few atoms in a burst or a few dozens of micrometers in a burst, with the same very thin heat affected zone at the surface. (Another is that all the stuff you just blasted off imme
Popular trife... (Score:5, Insightful)
The lovely word "may" is such an abused word. There are MANY things that MAY come, on the other hand it MIGHT not as well. My money is on that it won't be here anytime soon. There are so many technical and impractical issues that arise, that this is nothing more than a "wow...lasers, we're so 1337" 21 century etc. Sure, it makes for a good read, and even better...the house-geek will have his say over the dinner table...say...did you know honey, they're putting lasers in front of the trains now to clear the tracks. OOOOh honey, that's just up your Dart Vader alley!
Guess what? I've been working with technology and prototyping for years, and it's a riot every time this actually surfaces as an article once in a blue moon, you can't just put high power lasers in front of trains, you'll have reflection issues, IR-radiation, people claiming blindness, and the kind of power you need to "zap" it clean is extreme, this isn't your average laser pointer that can be used to write your name into a cellphone or pop balloons, heck...even hefty industrial lasers used to cut metal are so focused and concentrated that if you wanted to use it to blast away debris...you'd need a HECK of a lot more space for it to be actually practical, not to mention the need for cooling.
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In the /. meme world wouldn't it be "Trains May Soon Come Equipped With Sharks"?
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My country has these already! You can see them ... Oh, wait.
... if you believe!
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the practical issues of making it happen are the least of the concerns, trains are stupid big and have huge amounts of available power, and they can afford to carry a cooling system for a laser. it's all about the safety issues, which you also mentioned :)
Is Dr. Evil Behind This? (Score:2)
As it really sounds like he's moved on from the idea of sharks with frickin' laser beams.
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Only if the trains are shark shaped and if the project will cost *pinky finger to mouth* one MILLION dollars!
Laser Mounted Trains (Score:2)
Can they make the trains look like sharks? (Score:2)
Lighting fires in front of a train (Score:2)
Trains today... (Score:2)
Sharks tomorrow.
This should be interesting (Score:2)
Is this what trains will sound like in the future? [youtube.com]
Suicide (Score:2)
by fricking trains with lasers beams attached to their heads.
The Netherlands. (Score:3)
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The Netherlands? Now it all becomes clear.
There's only two things I hate in this world. People who are intolerant of other people's cultures and the Dutch.
Trains May Soon Come Equipped With Debris-Zapping (Score:2)
Trains May Soon Come Equipped With Debris-Zapping Lasers
That is... frickin awesome! How do I get a ticket? Can I work the laser?
Lasers should be rotated by 90 degree angle (Score:2)
Trains have more than 150 years of history of operations and the typical issues that the regular people hear about the trains is cost to tax payers. Remember the LIRR (Long Island Railway) scandal where 80% of retirees chose to be disabled and are drawing disability pensions http://en.wikipedia.org/wiki/L... [wikipedia.org] , section "Pension and disability fraud scandal".
Railroad companies know how to handle snow and and dirt.
However, everyone here should talk to their friend policeman, fireman or ambulance worker and ask
Not exactly a new idea (Score:2)
Here's an article talking about the same from 2002 [timeshighe...tion.co.uk]. Apparently there's rather low tech mechanical solutions that work quite well. Kinda like the laser potato peeler [nytimes.com], still waiting for that and my flying car.
frickin' laser beams (Score:2)
whee (Score:2)
If I find out which trains have this, I'm so going to post a youtube of a chipmunk or gopher on the track. He might have accidentally wandered onto a patch of duct tape.
Anyway, yeah in seriousness this sounds like nonsense.
No longer safe. (Score:3)
Note: Due to lasers, it is no longer safe to lye on the rails in front of oncoming trains.
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how about mild detergents instead of lye, would that be safe?
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Yes, but it will be safer for damsels in distress who get tied to railroad tracks. Laser, cuts rope, Superman can relax.
Laser those rascals... (Score:2)
When I took Amtrak to visit my parents in Sacramento in the 1990's, the kids in Oakland would put debris on the track to see what would happen when the train comes though at 65MPH. I don't mean a penny. Debris broke the brake airhose on the carriage underneath my seat on one trip. The trian slowed to a stop. The engineer spent 15 minutes repairing the airhose. Lasers should vaporize those little rascals off the track.
How do you not fry people's eyes? (Score:2)
Laser laboratories take rather elaborate precautions to avoid having a laser beam go into someone's eye. If there's much power in the laser, having it hit someone's eye is VERY bad--blindness can result. (And post signs that say 'do not look into laser with remaining eye'.)
Do we really want high power laser beams possibly bouncing off shiny rails going who knows where, where some poor bastard might be looking the wrong way?
I mean, even if these lasers aren't in the visible range, I still don't want a beam
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IOW, bar code readers.
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top websites - including Slashdot,
My sides!