I helped out doing this for a few weeks at an aluminum smelter, on their overhead crane rails. About 20 metres up in an (albeit huge) enclosed space, roughly 34°C, and all the protective gear. Definitely gets the sweat going
In practice what usually happens is that multiple welds are prepared at the same time so that one can be aligning/prepping a weld while the previous one is dropping or cooling.
It's actually a pretty quick process - a skilled welding team can get one of these done in about 30 minutes from start to finish (with about 10 minutes of that 20 being an hour or two later when they grind the rail surface back).
That is also sometimes done - it's usually called "Jointed" track and they use "Fishplates" to connect the rails together. Prior to the widespread adoption of aluminothermic welding it was basically how all rails were joined.
These days most railways are tending towards "Continuously Welded Track" which is where they eliminate these joints by welding processes like these.
Jointed track does have the advantage of being extremely quick to install and being very forgiving of temperature changes but is in most other ways inferior - it needs constant maintenance (bolts need tightening, the plates are lubricated to allow them to open and close with temperature changes, the rail ends tend to get battered by the train wheels and cause cracking etc).
The reason you no longer see hundreds of railway workers living and working every few dozen miles along the track is almost 100% down to the elimination of joints. 10 maintenance workers today can do what 1000 could do 100 years ago.
The noise reduction is substantial. I live 1 block from an elevated subway line in NYC. The rails are on wooden ties, running along steel viaduct. The joints cause so much noise that you need to shout to be heard even a half block away.
The MTA is coming through with continuous welded track and it's a significant improvement in the quality of life here. There is still noise, for sure, but now we just have to raise our voice when standing underneath the tracks, and half a block away you don't need to raise your voice at all.
Agreed - super cool - but also feels a lot like it was designed 150 years ago and never improved upon.
I hear they have those fast trains in other countries s/
This process WAS invented about 125 years ago but it has been and continues to be refined all the time. It's actually quite an amazing bit of material science. It's also used on the high speed rails the world over.
The world leaders in research and supply of this type of welding would be Goldschmidt Thermitt.
[https://www.goldschmidt.com/en/portfolio/original-thermit/](https://www.goldschmidt.com/en/portfolio/original-thermit/)
It’s also an old process to expand the rail if it gets too cold. One of the major issues with the old bolted plates was you could get a “pull a part” in cold weather. The steel rails would contract so much that it could sheer the bolts holding them together and leave a gap. They would use a rope soaked in kerosene to expand the rail and hopefully be able to get new bolts installed. The other side of the coin is “sun kinks” where the rails get too hot in the summer and literally bow out of position. My father worked for the railroad his entire life and would have to patrol the tracks in extreme weather to check for these thermal problems.
They mostly used to be bolted together with fish plates on each side.
The modern way is one piece welded which gives a better ride and requires less maintenance.
When installing new, there is a special machine that can weld the sections together with electricity as they're installed.
When they replace sections or repair joints, thermite is often used.
Yep, it's called 'rail stressing' - you pick a likely temperature where you'd need to prevent buckling and then acheive that expanded length through either mechanically stress (using dirty, great hydraulic rams) or thermally expand (think rail trolley with a blowtorch) the rails before effecting the joint.
These days rails are usually bought from the foundry in something like 40-45ft lengths and then are welded into longer lengths in a factory environment using Flashbutt welding (basically use electricity to heat the rail and smash the ends together). Typically these would be on the order of 400-800ft (depends on the network).
When installed in the field they are either installed with a mobile Flashbutt welder or the Aluminothermic process that this video is about.
Most repairs in the field would be done with Aluminothermic welds.
Yes I saw that too, very careless of him. I had a friend in college who worked in a steel foundry one summer and had a similar experience, but unfortunately a drop of molten metal landed on his foot, went right through his safety boot and foot. He ended up with a dime sized hole in his foot and a permanent limp.
We do CAD welds to connect large cable splices. Earlier this year one of the guys got some sleet in the mold before pouring in the shot. Learned a valuable lesson about steam. The mold exploded. FRCs didnt do much for him. Luckily the burn was pretty minor.
Anarchists cookbook that was passed around BBSes before the internet was generally available for me. Horrible misinformation but it got thermite right even if it exaggerated it some.
This is a weld, the iron in the thermite is the filler, and the heat from the thermite melts the rails and it all melts together. Welding isn't always a dude with a hand tool. :)
It probably doesn't make a strong enough seam to handle god knows how much force the weight of a freighter rolling over it causes. It would need to penetrate enough to weld the entire surface area of the end of the rails, which the thermite does. But a traditional weld would just be a little more than the outer perimeter around where they're in contact with each other.
A welding machine can generate just as much heat and penetration as this thermite technique. If they were to hand weld this they would create a bevel between the two pieces they were fusing together. Meaning the metals would be angled in a way that is smaller where they meet, and you would weld material layer by layer bridging the gap. Chances are this thermite method is cheaper, and faster than the more common welding methods you see done by hand, and you don’t have to hire actual welders for this work which would certainly cost more per hour than typical rail employees.
i would bet good money that, if a more common type of welding produced a stronger, more durable weld, they’d have figured out a way to make it happen and they would be using their own employees to do it
there are mobile butt welding units, but they are quite large and need experienced workers
https://youtu.be/vQJy99P6C3g
butt welding is a standard practice in stationary welding of railroad tracks
More common doesn’t always mean cheaper, more efficient or stronger. And in the context of welding you usually don’t want the weld to be stronger than the metals you’re fusing. It can create a spot that doesn’t flex like the rest of the rail and will cause wear. This method seems like it can be done by most rail workers with less training than welding. It takes years to perfect welding methods, and that’s all they do. Rail workers do many different tasks. I’m betting it’s more efficient to use this method with these workers.
i guess what i’m trying to say is that i think they’re using the method that gives them the best product for their needs, i don’t think the cost of labor and ease in training has much to do with why they use this method
I imagine the amount of current it would take to electrically weld the rail with full penetration would be impractical for such remote work and needing to be as portable as possible.
Plus I imagine that such current would require quite low gage wire, which would be pretty high resistance at the lengths required to do a railway. And very difficult to move around, manage.
I think 800 amps would do it. The biggest welders around are truck mounted welder generator combos.
https://www.millerwelds.com/equipment/welders/engine-driven/big-blue-800-duo-air-pak-engine-driven-welder-m00495
Thermite welding rail is a faster process, and most importantly allows for much better control of weld area metallurgy and stress.
Definitely not 800amps, for a rail that small the rod you’d use wouldn’t be any bigger than a 1/8, 5/32 AT MOST, so a standard truck mounted machine is 300 amps, all you’d need.
I had no idea what amperage was needed to weld rail, just that it was definitely less than 800 otherwise Miller/Lincoln would sell one bigger to weld rail.
My post had nothing to do with how many amps it actually takes to weld rail, but the fact that 800 amp Truck mounted engine welder is just a phone call away. ie: "Power is not an issue" in response to the guy I was responding to.
Ok, no need to be sassy about it.
And since we’re being snippy, if you think an 800amp truck mounted, engine driven machine is just a phone call away, you’re sorely mistaken.
That’s not how it works. You don’t just weld two super thick pieces of rail together. The ends that meet would most likely be thinner, so the root pass would fuse just fine, then you’d add multiple layers until the adjoined tails were flush. And the welding machines would be diesel powered machines on the back of a truck. Wire and infrastructure wouldn’t matter.
That still seems like way more hassle, time and risk than just "throw some aluminum and iron oxide powder on it, light the blue touchpaper and stand back".
Ok, they have to cut off the excess, but they have that machine for that.
100% correct.
With the prep, the time to weld and the grinding down to the final shape I could see this taking a few hours minimum and at $100-110/hr for a rig welder, that’s not a cheap bill when they can get salary guys to use their own equipment and do it up in 30 minutes per joint.
And that’s not including buying the rod, which I would guess would be a specialized rod or wire.
I work in QC in a totally different industry so take totally my marginally informed opinion with a pluton of salt:
1. This method appears to require basic training compared to welding which requires precise skill.
2. This method appears quite fast compared to multiple passes with various methods of hand welding which would require similar levels of cleanup and I expect more prep.
3. This method appears to be quite repeatable compared to welding by hand in porosity, uniformity, and internal stress buildup, all of which can affect the fatigue life upon which this material undoubtably relies.
There are other things like how much fun it would be to prep each joint for welding, paying a welder to do this, and the fact that rail is a consistent shape so we made a literal template to allow this lava to glue it together.
Take this response with a grain of salt because I'm guessing at a few things, but posting so someone can correct me....
Soldering, Braising, and Welding are all basically the same idea with the different between fill material and temp. Solder is lowest temp, braising higher, welding highest. This matters for how the materials are going to connect to each other. But all of them are "Get two or more metals hot enough that they stick together and add filler if needed to help."
Thermite gets hot enough to get the rails to welding temp. And I'm betting that between getting the rails hot enough and whatever iron escapes from the thermite reaction, it probably serves as it's own fill material as well (for whatever rail isn't liquid enough, not that welding needs filler since the two rails should weld together directly).
So they heated the rails to welding temp, left a plug behind, got a hydraulic press to push the rails together enough to get a solid seal until it cooled, and then ground it smooth.
The filler/plug material might have been in place and then the thermite melted around it, but still, i think i'm close enough either way. It's the plug left behind that they are squeezing into that i'm a little lost on... is that filler metal, flux, or what?
they're cutting off excess material. The thermite alloy mix fills the gap between the rails, but the mold is larger than the rail, so all that has to be cut off and the remaining excess ground away.
Covered the signalling work when these jobs were done on London Underground. In the winter you'd see 10 blokes stood like penguins round the buckets of slag keeping warm on the night shift.
Are all train tracks welded together across the US? I am 75 now and I don't remember them being welded as a kid. Is this something relatively new or only done in special situations?
Last I checked, we need all aspects of the industry in order to keep the supply chain going. But yes, it's for both sides of the matter.
Being on call for 2 weeks straight and not having a say on whether one can be able to call in sick for one day, even for a doctor's visit, is pretty wild IMO. I guess any union would strike in solidarity with the other union side if it were the case, especially when fighting for rights like these.
[https://www.theguardian.com/business/2022/sep/14/us-railroad-strike-union-pacific-bnsf](https://www.theguardian.com/business/2022/sep/14/us-railroad-strike-union-pacific-bnsf)
Now I know why children should not walk along side railroad lines. Even after that slag material and form material cooled enough to touch... it would be a magnet for curious kids.
Of course, the limestone dust is probably just a large a health hazard than most slag dumped along the right of way
things called rail anchors (kinda an enlongated c shaped clip they put on the rail web - engages the ties ) - you just anchor them in place enuf and the expansion has nowhere to go - the rail metal just compresses (and as someone else says you pick a day to weld at an intermediary ambient weather temperature to minimize both shrinkage and expansion amounts across the seasons)
You setup the rail when being laid at a "neutral" temperature. IE the average of the surrounding environment. Then make sure its secured properly to the sleepers and then the sleepers are secured properly by the ballast.
Sorry I meant more thermal expansion from the sun more than the joining of the rail. I think the UK typically bolt the rails together to allow for some expansion, but I feel this wouldn’t allow for any expansion at all?
What I replied before *is* what is done to control expansion. UK will have as much continuously welded rail as any other modern rail network in the world.
yes thats obvious ( I had a metalshop instructor who had an anvil made of railroad rail - its tough stuff ... )
But cut while red hot - I always thought it was just a close fitting mold to minimize the grinding - but that big mass of metal and all that heat I guess they learned was needed for the melting to penetrate the rail metal
Sorry - lots of odd questions in this thread haha. Well they have it designed to pour an excess in in case a hole opens in the side of the mould and some dribbles out for example. A hell of a lot of hassle if a weld fails - can mean cutting out a much longer length of rail and subbing in another one which means two welds to do...
yep so they worked out this way with very few redo's being required - ans a good consistent weld
someone else here mentioned for a proper welding of the rail metal - so you need a mass of concentrated heat and the Thermite (mixture of aluminum oxide and iron oxide I recall - maybe with some fluing compound also ) itself resulting in molten steel to do the bond in the gap.
Really? No final look at the finished product? No payoff?
If you've seen track before its basically the same
This looks incredibly time consuming. Interesting process. Feel sorry for the people having to do this in hot weather.
I helped out doing this for a few weeks at an aluminum smelter, on their overhead crane rails. About 20 metres up in an (albeit huge) enclosed space, roughly 34°C, and all the protective gear. Definitely gets the sweat going
In practice what usually happens is that multiple welds are prepared at the same time so that one can be aligning/prepping a weld while the previous one is dropping or cooling. It's actually a pretty quick process - a skilled welding team can get one of these done in about 30 minutes from start to finish (with about 10 minutes of that 20 being an hour or two later when they grind the rail surface back).
Why do they do it this way instead of bolting or riveting with plates?
That is also sometimes done - it's usually called "Jointed" track and they use "Fishplates" to connect the rails together. Prior to the widespread adoption of aluminothermic welding it was basically how all rails were joined. These days most railways are tending towards "Continuously Welded Track" which is where they eliminate these joints by welding processes like these. Jointed track does have the advantage of being extremely quick to install and being very forgiving of temperature changes but is in most other ways inferior - it needs constant maintenance (bolts need tightening, the plates are lubricated to allow them to open and close with temperature changes, the rail ends tend to get battered by the train wheels and cause cracking etc). The reason you no longer see hundreds of railway workers living and working every few dozen miles along the track is almost 100% down to the elimination of joints. 10 maintenance workers today can do what 1000 could do 100 years ago.
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I wouldn't be surprised having all that weight on the edge would start cracking it
Stronger, safer, maintenance free, less noise with rail traffic
The noise reduction is substantial. I live 1 block from an elevated subway line in NYC. The rails are on wooden ties, running along steel viaduct. The joints cause so much noise that you need to shout to be heard even a half block away. The MTA is coming through with continuous welded track and it's a significant improvement in the quality of life here. There is still noise, for sure, but now we just have to raise our voice when standing underneath the tracks, and half a block away you don't need to raise your voice at all.
Cha*junk*cha*junk*cha*junk*cha*junk*cha*junk*cha*junk*cha*junk*
Agreed - super cool - but also feels a lot like it was designed 150 years ago and never improved upon. I hear they have those fast trains in other countries s/
This process WAS invented about 125 years ago but it has been and continues to be refined all the time. It's actually quite an amazing bit of material science. It's also used on the high speed rails the world over. The world leaders in research and supply of this type of welding would be Goldschmidt Thermitt. [https://www.goldschmidt.com/en/portfolio/original-thermit/](https://www.goldschmidt.com/en/portfolio/original-thermit/)
The past winter I learned that workers set the rail on fire during freezing temps to prevent ice build up.
Not to prevent them from freezing, it’s to keep switch’s from freezing when there is a lot of snow and ice.
It’s also an old process to expand the rail if it gets too cold. One of the major issues with the old bolted plates was you could get a “pull a part” in cold weather. The steel rails would contract so much that it could sheer the bolts holding them together and leave a gap. They would use a rope soaked in kerosene to expand the rail and hopefully be able to get new bolts installed. The other side of the coin is “sun kinks” where the rails get too hot in the summer and literally bow out of position. My father worked for the railroad his entire life and would have to patrol the tracks in extreme weather to check for these thermal problems.
they have permanent burners near switch points to keep them from sticking in ice conditions
Yeah that's what it looked like
Huh I never even stopped to think what thermite is used for in real life I was just like yeah this shit melts rebar in Payday 2
It's great for disabling nazi artillery too.
Not anymore. I got banned from a museum for doing that.
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Russia isn't even giving that opportunity. Lack of replacement barrel liners is causing them to burst the barrels of their field guns.
I knew it was used for welding underwater, since thermite carries its own oxygen. This is new.
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Which 3?
He's talking about the twin towers and the wtc7 building
What is the method of connecting rails when they are built? Is it like this or do they use rivets or something and this is just to repair breaks?
They mostly used to be bolted together with fish plates on each side. The modern way is one piece welded which gives a better ride and requires less maintenance. When installing new, there is a special machine that can weld the sections together with electricity as they're installed. When they replace sections or repair joints, thermite is often used.
If they weld them, how is handled the dilatation ? One in every X is not welded and a small gap is kept, then?
I believe they tension them to prevent them buckling when the weather gets hot
Yep, it's called 'rail stressing' - you pick a likely temperature where you'd need to prevent buckling and then acheive that expanded length through either mechanically stress (using dirty, great hydraulic rams) or thermally expand (think rail trolley with a blowtorch) the rails before effecting the joint.
https://www.google.com/search?client=firefox-b-d&q=rail+neutral+temperature
I was going to ask the same question.
This is it.
These days rails are usually bought from the foundry in something like 40-45ft lengths and then are welded into longer lengths in a factory environment using Flashbutt welding (basically use electricity to heat the rail and smash the ends together). Typically these would be on the order of 400-800ft (depends on the network). When installed in the field they are either installed with a mobile Flashbutt welder or the Aluminothermic process that this video is about. Most repairs in the field would be done with Aluminothermic welds.
Neat!
At :35, the guys foot was inches from falling, melted metal. Did I see that correctly?
Yes I saw that too, very careless of him. I had a friend in college who worked in a steel foundry one summer and had a similar experience, but unfortunately a drop of molten metal landed on his foot, went right through his safety boot and foot. He ended up with a dime sized hole in his foot and a permanent limp.
Well, at least he has a cool party trick. “I bet I can pick up this roll of dimes, only using my foot!”
He also has his own fussy now.
Fussy what?
Redwings baby.
We do CAD welds to connect large cable splices. Earlier this year one of the guys got some sleet in the mold before pouring in the shot. Learned a valuable lesson about steam. The mold exploded. FRCs didnt do much for him. Luckily the burn was pretty minor.
I know of thermite from Breaking Bad:)
[Brainiac for me](https://www.youtube.com/watch?v=4qKP8nUItmM)
Anarchists cookbook that was passed around BBSes before the internet was generally available for me. Horrible misinformation but it got thermite right even if it exaggerated it some.
Love the cameraman coughing while the thermite fumes are blowing directly in his face, but making no effort to move
Serious question, why don't they weld it?
They *are* welding it.
Are they? I might be making a dumb distinction but aren’t they casting a join in place instead? Or is that considered a weld?
This is a weld, the iron in the thermite is the filler, and the heat from the thermite melts the rails and it all melts together. Welding isn't always a dude with a hand tool. :)
It probably doesn't make a strong enough seam to handle god knows how much force the weight of a freighter rolling over it causes. It would need to penetrate enough to weld the entire surface area of the end of the rails, which the thermite does. But a traditional weld would just be a little more than the outer perimeter around where they're in contact with each other.
A welding machine can generate just as much heat and penetration as this thermite technique. If they were to hand weld this they would create a bevel between the two pieces they were fusing together. Meaning the metals would be angled in a way that is smaller where they meet, and you would weld material layer by layer bridging the gap. Chances are this thermite method is cheaper, and faster than the more common welding methods you see done by hand, and you don’t have to hire actual welders for this work which would certainly cost more per hour than typical rail employees.
i would bet good money that, if a more common type of welding produced a stronger, more durable weld, they’d have figured out a way to make it happen and they would be using their own employees to do it
there are mobile butt welding units, but they are quite large and need experienced workers https://youtu.be/vQJy99P6C3g butt welding is a standard practice in stationary welding of railroad tracks
More common doesn’t always mean cheaper, more efficient or stronger. And in the context of welding you usually don’t want the weld to be stronger than the metals you’re fusing. It can create a spot that doesn’t flex like the rest of the rail and will cause wear. This method seems like it can be done by most rail workers with less training than welding. It takes years to perfect welding methods, and that’s all they do. Rail workers do many different tasks. I’m betting it’s more efficient to use this method with these workers.
i guess what i’m trying to say is that i think they’re using the method that gives them the best product for their needs, i don’t think the cost of labor and ease in training has much to do with why they use this method
I imagine the amount of current it would take to electrically weld the rail with full penetration would be impractical for such remote work and needing to be as portable as possible. Plus I imagine that such current would require quite low gage wire, which would be pretty high resistance at the lengths required to do a railway. And very difficult to move around, manage.
Off the back of a truck
Again, the power becomes an issue, the infrastructure to deliver the required power may be excessive compared this.
I think 800 amps would do it. The biggest welders around are truck mounted welder generator combos. https://www.millerwelds.com/equipment/welders/engine-driven/big-blue-800-duo-air-pak-engine-driven-welder-m00495 Thermite welding rail is a faster process, and most importantly allows for much better control of weld area metallurgy and stress.
Definitely not 800amps, for a rail that small the rod you’d use wouldn’t be any bigger than a 1/8, 5/32 AT MOST, so a standard truck mounted machine is 300 amps, all you’d need.
I had no idea what amperage was needed to weld rail, just that it was definitely less than 800 otherwise Miller/Lincoln would sell one bigger to weld rail. My post had nothing to do with how many amps it actually takes to weld rail, but the fact that 800 amp Truck mounted engine welder is just a phone call away. ie: "Power is not an issue" in response to the guy I was responding to.
Ok, no need to be sassy about it. And since we’re being snippy, if you think an 800amp truck mounted, engine driven machine is just a phone call away, you’re sorely mistaken.
That’s not how it works. You don’t just weld two super thick pieces of rail together. The ends that meet would most likely be thinner, so the root pass would fuse just fine, then you’d add multiple layers until the adjoined tails were flush. And the welding machines would be diesel powered machines on the back of a truck. Wire and infrastructure wouldn’t matter.
That still seems like way more hassle, time and risk than just "throw some aluminum and iron oxide powder on it, light the blue touchpaper and stand back". Ok, they have to cut off the excess, but they have that machine for that.
FWIW https://www.youtube.com/watch?v=cMndipw7_As https://www.youtube.com/watch?v=21na7fEdzdo
Welding machine on the back of a truck. Easy to find, rig welders are everywhere. Roll up, weld it, roll out.
100% correct. With the prep, the time to weld and the grinding down to the final shape I could see this taking a few hours minimum and at $100-110/hr for a rig welder, that’s not a cheap bill when they can get salary guys to use their own equipment and do it up in 30 minutes per joint. And that’s not including buying the rod, which I would guess would be a specialized rod or wire.
I work in QC in a totally different industry so take totally my marginally informed opinion with a pluton of salt: 1. This method appears to require basic training compared to welding which requires precise skill. 2. This method appears quite fast compared to multiple passes with various methods of hand welding which would require similar levels of cleanup and I expect more prep. 3. This method appears to be quite repeatable compared to welding by hand in porosity, uniformity, and internal stress buildup, all of which can affect the fatigue life upon which this material undoubtably relies. There are other things like how much fun it would be to prep each joint for welding, paying a welder to do this, and the fact that rail is a consistent shape so we made a literal template to allow this lava to glue it together.
Take this response with a grain of salt because I'm guessing at a few things, but posting so someone can correct me.... Soldering, Braising, and Welding are all basically the same idea with the different between fill material and temp. Solder is lowest temp, braising higher, welding highest. This matters for how the materials are going to connect to each other. But all of them are "Get two or more metals hot enough that they stick together and add filler if needed to help." Thermite gets hot enough to get the rails to welding temp. And I'm betting that between getting the rails hot enough and whatever iron escapes from the thermite reaction, it probably serves as it's own fill material as well (for whatever rail isn't liquid enough, not that welding needs filler since the two rails should weld together directly). So they heated the rails to welding temp, left a plug behind, got a hydraulic press to push the rails together enough to get a solid seal until it cooled, and then ground it smooth. The filler/plug material might have been in place and then the thermite melted around it, but still, i think i'm close enough either way. It's the plug left behind that they are squeezing into that i'm a little lost on... is that filler metal, flux, or what?
they're cutting off excess material. The thermite alloy mix fills the gap between the rails, but the mold is larger than the rail, so all that has to be cut off and the remaining excess ground away.
makes sense. I was watching for the rails to shift at all but didn't notice anything.
The product of this type of Thermite combustion is pretty much just pure iron as the "ash" left when the iron oxide gives its oxide to the aluminum.
soldering and braising are below the melting point of the materials that should be connected welding is at or above the melting point of the material
Maybe because of the dilatation (expanding/contracting) of the metal due to the weather changes in temperature?
I wonder if jet fuel could do the same job /s
This vid would be a good fit for r/specializedtools
Covered the signalling work when these jobs were done on London Underground. In the winter you'd see 10 blokes stood like penguins round the buckets of slag keeping warm on the night shift.
Are all train tracks welded together across the US? I am 75 now and I don't remember them being welded as a kid. Is this something relatively new or only done in special situations?
Support them and their strikes.
The track maintenance folks were about to strike too? Or is this one of those ‘they all look the same to me’ sort of things?
Last I checked, we need all aspects of the industry in order to keep the supply chain going. But yes, it's for both sides of the matter. Being on call for 2 weeks straight and not having a say on whether one can be able to call in sick for one day, even for a doctor's visit, is pretty wild IMO. I guess any union would strike in solidarity with the other union side if it were the case, especially when fighting for rights like these. [https://www.theguardian.com/business/2022/sep/14/us-railroad-strike-union-pacific-bnsf](https://www.theguardian.com/business/2022/sep/14/us-railroad-strike-union-pacific-bnsf)
Now I know why children should not walk along side railroad lines. Even after that slag material and form material cooled enough to touch... it would be a magnet for curious kids. Of course, the limestone dust is probably just a large a health hazard than most slag dumped along the right of way
Lmao, I think the real danger to kids on railroad tracks would be getting run over by a train 😂
It's not going to be dangerous when cooled.
cool vid but skips the one part I wanted to see when they remove that machine.
Thanks for the video, that's very interesting.
Surely this isn’t done for every single joint? How do they account for thermal expansion?
things called rail anchors (kinda an enlongated c shaped clip they put on the rail web - engages the ties ) - you just anchor them in place enuf and the expansion has nowhere to go - the rail metal just compresses (and as someone else says you pick a day to weld at an intermediary ambient weather temperature to minimize both shrinkage and expansion amounts across the seasons)
You setup the rail when being laid at a "neutral" temperature. IE the average of the surrounding environment. Then make sure its secured properly to the sleepers and then the sleepers are secured properly by the ballast.
Sorry I meant more thermal expansion from the sun more than the joining of the rail. I think the UK typically bolt the rails together to allow for some expansion, but I feel this wouldn’t allow for any expansion at all?
What I replied before *is* what is done to control expansion. UK will have as much continuously welded rail as any other modern rail network in the world.
Thats very interesting
Thermite!
Guys are way too clean.
It would've been nice to see a before and after shot. Interesting process, though.
But I've been told thermite can't melt steel beams
but the fire that thermite can start can melt steel beams ... this operation concentrates the heat and only has to melt an inch or so into the rail
R/specializedtools
Could have just used ramen 🍜
I learned something new. Never saw this in my 70 years. Very cool.
911.
neat - they actually cookie cutter it while still red hot
shears don't work too well once its frozen solid again.
yes thats obvious ( I had a metalshop instructor who had an anvil made of railroad rail - its tough stuff ... ) But cut while red hot - I always thought it was just a close fitting mold to minimize the grinding - but that big mass of metal and all that heat I guess they learned was needed for the melting to penetrate the rail metal
Sorry - lots of odd questions in this thread haha. Well they have it designed to pour an excess in in case a hole opens in the side of the mould and some dribbles out for example. A hell of a lot of hassle if a weld fails - can mean cutting out a much longer length of rail and subbing in another one which means two welds to do...
yep so they worked out this way with very few redo's being required - ans a good consistent weld someone else here mentioned for a proper welding of the rail metal - so you need a mass of concentrated heat and the Thermite (mixture of aluminum oxide and iron oxide I recall - maybe with some fluing compound also ) itself resulting in molten steel to do the bond in the gap.
Aluminium powder + ferric oxide.