Why Don’t Railroads Need Expansion Joints?

[@veritasium]

Get an exclusive 15% discount on Saily data plans! Use code veritasium at checkout. Download the Saily app, or go to saily.com/veritasium

[@iamnotdarshan]

Happy new year derek!

[@XaviLR]

@@iamnotdarshan happy new year!!!

[@detXCI]

How can ur comment posted 1 hour ago while the vids itself came out 7 min. Ago... Wait bro's the poster..

[@TheChrisLeone]

HI DEREK!!! Love your content, I've been following you as long as I can remember at this point. Much love!

[@guysumpthin2974]

So,,, why in Germany?

[@nikc1313]

As a train driver this was absolutely fascinating. Really gives me an appreciation for what the engineers do through the night when I clock off. Great video.

[@danielbum912]

@@nikc1313 thank you for your service!

[@e.e.4695]

@@danielbum912 What service? It's a job, he makes money, that's it.

[@maxwellsimon4538]

@@e.e.4695 Money is used for the purchase of goods and services. Transportation is a service, so a train driver provides a service.

[@danielbum912]

@@e.e.4695 How are these things mutually exclusive? I hate to break it to you but public services are provided by actual people doing their actual jobs. Just because _some_ peoples' jobs is to market cryptocurrencies or to invent the 3,255th dating app (or any other job that makes money but doesn't provide any worth to society) doesn't mean this person's job isn't, per definition, a public service. I'm grateful for anyone driving a train or maintaining my water supply grid rather than being a real estate agent or an Instagram influencer.

[@FantasticOtto]

@@e.e.4695 You can say the same thing about soldiering.

[@Garf_Is_King]

3:50 "all experiments were performed under the supervision of professionals with proper safety precautions" all while homeboy is using a torch with the ciggy still lit, God bless.

[@PixelatedLlama]

jordan?

[@Infernoblade1010]

The cigarette shows he's a pro

[@mamutero21]

All welders usually smoke if they want, nobody is going to say no unless a big boss is around. Thats because you weld things way way hotter than a cigarette and they are exposed to way more dangerous gases than a simple cigarette, add the heat around, the heavy and dangerous job and you will see cigarettes like a soda.

[@MrSchmallz]

Smoking and metal fabrication go together like peas and carrots. It's in the bible I think. 😂

[@noneck3099]

...and no glasses whilst grinding....

[@davidgriffiths827]

I've been working as a metallurgist in rail manufacturing, welding, and failure analysis around the world for 40 years and this is far and away the best explanation of the thermite welding process that I have ever seen.

[@JO-df3ob]

Thanks for all your hard work!

[@arjanvanraaij8440]

The techs at Goldschmitt are verry proud of that their making. This is German engenering at its best.

[@MrNicoJac]

Can I ask why "normal" hand welding does not work for rail? (or at least worse than thermite) It would seem (at first glance) that you could also shave down any excess material from the weld, like they already did here. (if I Googled correctly, I suspect FCAW would be needed/easiest for rail tracks?) Would be interested to learn why this isn't the standard :)

[@numeroVLAD]

@@MrNicoJacnormal welding cannot handle that thickness. That is the short answer. The longer explanation can be deducted from the video where different zones and steel microstructures explained.

[@Clynikal]

@@MrNicoJacwire feed welding is used extensively. Thermite is just the focus the narrative for this video.

[@Guy_Incognito118]

3:55 the timing of saying "proper safety precautions" while showing a guy using a cutting torch with a cigarette in his mouth is underrated

[@conanobrennan53]

A lot of US class 1 railroads also require way more personal protection equipment/safety that you see in this video. Some of that extra safety is due to liability the US railroads face when workers get hurt though.

[@ChadKakashi]

Cigarette adds professionalism. You *know* that guy can do that job blindfolded.

[@JamesFolkers]

@@ChadKakashiNo I don’t…

[@elctwenty1328]

he is the exact image i'd have in my head of a railroad welder who knows what he's doing

[@scaredcrower]

I don't know how you all noticed that

[@Chiltonization]

7:45 that ash on the cigarette is amazing! Artist at work.

[@volvo09]

How does that not fall off! Wow

[@SS-ve7tt]

I don't smoke, but how in the world does that not fall off? That dude must be dragging hard on that thing.

[@Shaker626]

You can tell he isn't going to put his hands on it again until that rail is set up tight.

[@nixellion]

I was looking for a cigarette comment. When you see someone working with a cigarette you pretty much know they know what they are doing. And the longer the ash the better they are :D

[@TheOfficialOriginalChad]

I have no clue how people can keep their eyes open with the cig smoke in their eyes.

[@JeffGeerling]

I also learned recently thermite is used to form continuous copper ground bonds at broadcast tower sites! It's cool to see it in action.

[@mrfoodarama]

And to cook Hot Dogs! (I couldn't resist) Happy New Year Jeff

[@JeffGeerling]

@@mrfoodaramahappy new year! Hot dogs, bratwurst, you name it, I'll make it talk!

[@mycosys]

@@JeffGeerling Even AI XD

[@greenmachine5487]

Yes, I used to do that at cell phone tower sites. We called it CAD welding.

[@crimsonghoul8983]

​@@JeffGeerling Happy new year, Jeff. Wasn't expecting to see you here.

[@MegaBassThumper]

I was a foreman on rail thermite crews for about 6 years, and this video is awesome! They need to start showing this video in our training classes. We get the handbook and go over what we should/shouldn't do, but gloss over a lot of 'why' we should/shouldn't do these things. It's also interesting to see the little differences in welding procedures, one I noticed was that after we shear the weld, we put an insulating jacket over the rail to slow the cooling process even further. Another is when first fitting the two halves of the mold to the rail, we hold the molds tight to the rail and grind them against eachother side to side to help get a tight seam. Not as necessary on new rail, but essential on old worn-out tracks. Looking forward to the next video!

[@getaclassphys]

The best comment, I think.

[@baltulielkungsgunarsmiezis9714]

Its always useful to educate yourself more on your job, it would just be nice if you got payed for it instead of having to do it in your free time for free.

[@eerysimps]

The box you are talking about I believe is what we call an 'Muffler' used for specific rail grades (don't ask me to quote the rail grade because i've never had to use the muffle box) otherwise the welds break. Rubbing the molds is just good practice for new to new rails. Having the molds nice and tight will stop any 'flashing' forming around the welds. Then there is old to new rail that when welded require 'Spot' Moulds. These molds have extra material on them and need adjusted to fit the specific rail section you are welding. I agree it is interesting watching others do the same process with slight changes!

[@Esablaka]

In Germany "Gleisbauer" (rail builder) is a 3 year vocational education / apprenticeship . Similar to other vocational education "degrees" it's an alternative to a university degree. It's paid and usually about 50% working at a company and 50% at a specialized school teaching you the necessary information and skills to really do the job properly. At the one one gets a paper that proofs that one has the proper qualifications for the specific job. Almost all trades (and also jobs that require university degrees in other countries like for example becoming a nurse) in Germany are done by people who have passed through such a tertiary education path. It's often a true and proper alternative to university degrees. The vocational training/education / apprenticeship system in Germany and some surrounding countries really leads to excellent skilled workers who also understand the deeper science and reasonings behind what they are doing.

[@gandydancer823]

Got to love that CWR training. As a section foreman and track inspector I had CWR training every year

[@jajamuc]

As a German railway customer, I hope I will soon feel the effects of these guys craftsmanship in my daily customer experience.

[@offshorebear]

The question was "Why don't railroads need expansion joints" the answer was "we mechanically restrain them" and viola, a 27 minute video. Fine, subscribed.

[@AttilaAsztalos]

Too bad it ended up being a non-answer, after a 27 minute video. If simply bolting down the rails (which was happening back then too) is enough to prevent expansion and buckling, why were they worried about them in the past?

[@Triple_J.1]

@@AttilaAsztalos They are welded at a median temperature, at night, so the maximum expansion and contraction are limited to a certain lower value. The welded rails resist deflecting, so they are not prone to deflect into an angle at the joints. Any minor deflection is likely sinusoidal. Steel has a known coefficient of thermal expansion. And environmental data is widely available for all geographic locations now. Not so in the early days. Also, they are not constructing railways as rapidly as they were in the past. So there is no need to work as fast, or throughout the day, as in times past.

[@grindcorgz]

@@AttilaAsztalos either you didnt watch the video or you didnt understand the answer because he explained it perfectly lol

[@muneeb-khan]

@@Triple_J.1thank you, I also felt the title wasn’t fully answered in the video. Did learn a lot about material science and welding at least.

[@ObjectsInMotion]

@@grindcorgz either you didnt read the comment or are too ignorant to understand it, because the video never once mentioned why people in the past didn't know mechanical restraint was enough to prevent expansion and buckling. Because its true that they did not.

[@Felixpotluck]

I did this for about a year with terrible pay. Back breaking daily work, really makes you appreciate the things that go on behind the scenes to keep a solid infrastructure going.

[@JO-df3ob]

Thank you for your work!

[@BabyMakR]

I spent about 3 weeks taking an old rail line apart, unpaid. It was 'work for the doll' in Australia. The rail was gone but we had to take the big nail things out with huge wedges that look like the claw on a hammer. Had to knock them in with a normal hammer and then, I was on the big 10kg sledge hammer and had to hit down on it to knock the nail out. Sometimes it would shoot into the air like a bullet and everyone would bomb to get away from it. Then, 2 weeks later I got to make big garden beds out of the old sleepers we recovered. Again, unpaid.

[@dickard8275]

Makes you appreciate men!

[@wobblysauce]

@@BabyMakR unpaid loose term.

[@diedampfbrasse98]

Not the worst paid job here in Germany / Western europe and the benefits are good, but given how harsh the work can be still not paid well enough compared to the millions of cushy desk jobs. Not surprised that in lesser developed countries these are the jobs which are truly terrible, but then again its the workers fault for not uniting and fighting for a fair share. One would think people able to do a hard job would be able to fight for decent pay, especially as so many first world economies showed them how and what is possible.

[@jbran7817]

7:50 how to spot a professional: it’s the guy chain smoking while working with both hands

[@attilasartorius]

My exact toughts!

[@micahhorton5252]

Word

[@jackbauer123321]

Dat ash 😂

[@Wes-x9p]

Or an addicted Fool.

[@JustAGooseman]

​@@Wes-x9pMost people who are laborers are smokers. This has been the case for hundreds of years for a reason lol. It helps with stress and numbs the back pain that is always present when working in a labor.

[@K.D.Fischer_HEPHY]

This really shows the work of those every day work heroes that most likely do not get the deserved appreciation.

[@KonkaBass]

I don't know why but this video, this series, has felt like what I remember the discovery channel being. That channel has stopped being like that years ago but I'm glad Derek is here to carry the torch on.

[@amesaeotrono]

Veritasium could be a whole channel on itself, hosting not only derek, but many other educational projects! I feel the same as you about it!

[@OlegSidorenko1974]

Exactly my impression too. It's interesting how vlogging first became a refreshing alternative to science documentaries but then just merged to refresh them and redefine the genre. Excellent, excellent stuff for the curious mind.

[@happydays334]

the correct way to start a new year!! Thank you Veritasium

[@johnkesich8696]

A video on how thermite turned the WTC into rubble might have been better.

[@connorgerrard-ky7ln]

Dull

[@happydays334]

Ok

[@mohnchichi]

When you heard "rail" and "line" amidst the new years cheering, I don't think this video was what your friends were calling for.

[@Darkknight512]

The footage of the preheating with glass is fantastic.

[@jovetj]

I am amazed they found glass that can handle the temperature and temperature gradient!

[@That_Student_]

​@@jovetjFor real. Normal glass would probably have turned black really quick.

[@emilen2]

​@That_Student_ It would have cracked and/or melted. No discolouring though. They might be using fused quartz or other exotic high temp glass.

[@That_Student_]

@@emilen2 Oh, then thanks for clearing it up! I often saw glass turning black in experiments in school or in a fireplace. That must have been a other type of glass then?

[@sanjayvaradharajan]

@That_Student_ do you know the name of the glass?

[@davidwilliamallen]

Veritasium on a generational run right now. Great to see this lovely long term channel grow.

[@Litepaw]

Man who started out as a theoretical physicist on youtube turned into promoting something learned at trade school :) respect man.

[@mf--]

In North America, railroads and contractors teach in rail yards and on track.

[@baltulielkungsgunarsmiezis9714]

Science and engeneering are linked strongly, one is reaserch twods anything and everything the other is aplication for findings useful.

[@Octoschizare]

Derek was never a theoretical physicist though (like some of the scientists you can see on the Sixty Symbols channel). He was always grounded in real-world practicality. I think his grad-level background is in methods of teaching and communicating physics, which involves a lot of demos.

[@revolvency]

@@Octoschizare his bachelor is on engineering physics, his later Phd is on science communication

[@sinnder]

Smarter Everyday ;)

[@xtianeskay5166]

Derek, your thermite videos part 1 and now part 2 are the most detailled science videos on your channel. I mentioned it on a comment under the first video: i think Goldschmidt did an extraordinary good job on conveying not only an overview of the topic but letting all of us be part of all the technical details of thermite. They took a lot of their working time to not be productive and instead showing you all of the process. I think the videos you created from all that information make a lot of young people getting involved into technical jobs - that is awesome! And now that I hear that you have collected enough material to even create a third video I am really overwhelmed. Great job, Derek! Great job, Goldschmidt! Solche Unternehmen brauchen wir! ❤❤❤❤❤

[@AxelHoeschen]

Thank you so much! It was a lot of work, but it also was a lot of fun. Also we don't get to do this every day. Plus: explaining what you are passionate about, what fascinates you and why is never a waste of time!

[@xtianeskay5166]

@AxelHoeschen Danke.... Ich finde es schön, dass ihr es als keine Zeitverschwendung anseht, und gleichzeitig finde ich es einfach bemerkenswert, dass ihr euch diese Zeit dennoch nehmt, weil in eurer Arbeitszeit kein direkter wirtschaftlicher Mehrwert generiert wird, was vielen Unternehmen aber sehr wichtig ist. Und das, wo ihr nicht mit 1-2 Personen für ein halbstündiges Interview zur Verfügung gestanden habt, sondern mit einem ganzen Team mehrere Tage! Ihr seid einfach super geil, ich feiere euch tierisch ab! 😀 Ein frohes, glückliches und gesundes neues Jahr 2025! 🍀🎉

[@annacoeptis]

grateful

[@PureMagma]

​@@AxelHoeschen I would love to know more about other applications that Thermite could be beneficial (besides railroad steel) ...like fabrication, automotive steel, steel in skyscrapers... This topic could become a much longer series!

[@1989Nihil]

@@xtianeskay5166 Wer weiß, vielleicht hat dieses Video ja bei einigen das Interesse geweckt die Ausbildung bei Goldtschmidt Smart Rail Solutions zu machen? Das Video hätte sich dann zumindest aus dieser Perspektive wirtschaftich gelohnt.

[@uzaiyaro]

I was waiting for a train many years ago, and they had just upgraded to concrete sleepers. These need continuous welded rail, so they were doing the welds on that night. I showed interest, and they got me down off the platform onto the track, and they let me hold the torch and light one of the ceramic pots off. I’m proud to say that a main line has one of my welds.

[@kitefan1]

I just got to see all the stuff sitting still from an overpass bridge. Jealous. 🙃

[@uzaiyaro]

@ I’d love to work in the railways but it’s a very competitive field, especially for a train driver or guard, which is what I’d like to be. Also back in the day I would often get cab rides, and sometimes they’d even let me handle the regulator, or the train equivalent of a throttle. Being a kid and in control of about 4,000 horsepower worth of electric motors was amazing. It’s something I’d about kill to experience again.

[@jonslg240]

As a socal resident, I can assure you that in many places there are still fishplates and still the old "tacktack" sounds in many places =p

[@jonslg240]

100% chance that anyone in the world will ride over one of these is 😂 There's plenty of people who will never ride on a train in their lifetime, just like there are plenty of people who won't fly on a plane in their lifetime. *To blow your mind further: there are MILLIONS of people who die every year without ever riding in an automobile in their lifetime.*

[@ey3796]

Could you please explain the part where they angle the rails before pouring the liquid metal? What goes wrong if you keep the rails flat on the ground? Thank you

[@Steffen-h7v]

18:50 reminds me of a place I worked at once. They are a small German company that makes the software for a process that results in surfaces that probably everyone has touched thousands of times. If you have ever been in a car or train or airplane, you have touched one of those surfaces. The company has 25 employees. They could single handedly hold the production of most consumer goods production in the world with a few clicks. It was astonishing to see how many small companies are involved in everything we take for granted.

[@samx1555]

I worked at Sydney's central station as a structural engineer during a rail shut-down weekend for maintenance. The rail technicians were doing rail welding and were kind enough to explain this whole process and mechanics. They were working under a time constraint so i didnt want to bother them. It was so cool seeing a deeper dive on this and knowing the basics of everything they taught me in a 5mins conversation.

[@Voyagerthe2nd]

I assume you were also there working with the track technicians during the STAR2 possession in December last year when they were building the tracks to platforms 11-14

[@samx1555]

@Voyagerthe2nd unfortunately no this was around early last year, from memory those platforms were either the ones they were working on or it was near by because it was the above ground platforms.

[@napyaninja]

I was looking for someone to write this, i always wondered what they do every public holidays to repair the line in Sydney.

[@juraj_b]

was also thinking about Sydney trains and how much flack they take for any downtime. it's hard when there's so many pieces that can go wrong plus things like welding and reduced funding. great stuff for making it work as smoothly as it currently does

[@tjaydagreat]

As a welder, I thank you for your appreciation of what we do.

[@farzaadkhaan]

I was managing a railways superstructure construction team in my country. There we made 65000 rail welds. Later I moved to Halle city in Germany were the video was made. Nowadays I am doing something else but the video meant a lot to me. I missed all my hardworking colleagues in railways industry. When you ride safely on a train please do not forget those sweaty faces.❤

[@SmokinOak]

Just out of curiosity, How many people were on your crew, and how many welds a day could could you get done. I spent a couple years on a welding crew working on Steel gang years ago. There were two crew of 3 people and we were able to do 12-14 welds a day.

[@farzaadkhaan]

@SmokinOak we had 3 methods Enclosed Arc Welding (EAW), Thermit and Flash butt, depending on the project. Flash butt was rental and we supplied ~10-15 worker per car plus forman and 3 technical people and track safety officers etc. Workers were opening and closing the fastening systems and grinding the welds etc. The Thermit was normally used on switches and end points of projects and sometimes per request on the track. The technical crew per trolley was 2. They used to weld 2 joints per 45 min. But each 2 two certified welders had a team of workers depending on the type of work for grinding, fastening opening and closing, cutting, rough alignment etc. Similarly track officers, team leader, inspectors, formen etc was there per few trolley. On average each troley welds 6 - 10 welds per day. For a long time we also used EAW. In EAW we had 1 bigger trolley containing 1 diesel generator and two welding transformer/rectifier. Each troley had 2 meister certified welder, 2 assistants (trainee), 2 fit up experts, 2 motorists for opening and closing the fastening systems, 1 rail cutter (normally was the same os foreman), and 4 simple workers. Each trolley used to make 12 to 20 welds per day. Similarly we had track officers, each 2-6 trolley had a workshop leader, and a team of 2 inspectors.

[@robotnikkkk001]

.....HIERARCHIAL TRUTH IS so POTENT THERE,THOUGH.......LIKE _IF U KNOW SO much,THEN HOW MUCH THE COST OF REPLACING A DAMAGED PART OF RAIL is_ ??? ...LIKE,TRAINS,ESPECIALLY freight ONES,JUST *love* TO MESS UP WITH RAILS,RIGHT????SO,IT'S LIKE okay SOMEWHAT IF WEATHER CONDITIONS ARE JUST RIGHT,BUT if THEYRE NOT???......WAIT FOR GOOD WEATHER??? ....ALSO HOW much WORK TO ACTUALLY replace A PIECE???A lot!!!!!WITH ALL THAT CUTTING ETC ETC ETC ETC ......RIGHT???.......AND STUFF AND STUFF AND STUFF .....COMPARED TO just unscrew,throw away old one,set a new one,screw back.........THAT'S IT!!!!.... .....SO,I'D RATHER TO not STOP ON SCIENTIFIC RESEARCH ABOUT how make a perfect rail joints!!!UNTIL FIND THE PERFECT ONE WHICH WILL BE both silent and low maintainance costs!!!AND EXPERIMENT WITH ANGLED ONES......AND different ANGLES........ ..SORRY FOR THE THING BUT *_i'm against welding rails_*

[@ey3796]

Could you please explain the part where they angle the rails before pouring the liquid metal? What goes wrong if you keep the rails flat on the ground? Thank you

[@farzaadkhaan]

@ey3796 the rail makes some contracting forces upon cooling down. The force on the head is more than the force on the bottom. So the rail becomes concave. We need to bring the rail up, depending on the technique and the heat input, to cancel it out with some safety margins.

[@H3rrJ3h]

My grandpa was a german engineer from Essen Germany and has numerous patents regarding these clamps that lock the railroad in place and the whole setup with welded Rails. So a little shout out to my long dead Grandpa Waldemar Bingmann! I miss you!

[@TheKnaeckebrot]

schon 1939 promoviert, glaub er hat Jahrzehnte deutsche Eisenbahngeschichte geprägt :)

[@gavinmurrell3415]

One of humanities heroes! May he rest in glory..

[@Steffen-h7v]

Gruß in den Eisenbahnerhimmel, lieber Waldemar!

[@EagleEyeShooting]

I worked as a signal maintainer for BNSF Railway for 15 years. Went to many trouble calls for broken rails. In the desert, the thermal expansion and contraction is an understatment. Broken rails are the root cause of train delays in what my territory was called "The Transcon" during peak season. This was the squeeze from shipment that got offloaded from the bays in California, any delays here set the schedule on delivery to our clients like UPS, FedEx ect. Peak season starts the day after Thanksgiving all the way till the first week of January. This is also the worse time period for broken rails. Needless to say, I spent a growing bond between my track supervisors and track department, often helping my fellow brothers weld rails even though I was in the signal department. We all had a goal when the trouble call took place early morning 3AM... 4hr drive in the middle of nowhere, we all wanted to get the job done as fast but as safely as possible. This video was a great documentary to the insight of this process

[@timespace6525]

Who care?

[@bradboyer1381]

They say that lieutenants worry about tactics, colonels strategy, but generals, generals, they worry about logistics. Point being, the older I get, the more I worry, worry about infrastructure. So, I super enjoy vids like this, the science, and art, behind everyday infrastucture upon which we all depend. Thinking about what others do not normally think about: I call that entertainment. And yet deeply educational. Overall, so satisfying. Thank you.

[@A.Filthy.Casual]

Is this why growing up in the 90s/00s i constantly saw commercials for "TONS AND TONS OF TRAINS! Old trains! New trains! Fast trains, slooow trains! Even trains from around the world!"?

[@facescomix]

​@@A.Filthy.Casual you just unlocked a memory in me!

[@darksu6947]

Going by your username I'm guessing you were born in 1381. That's a long time to worry about infrastructure. Also, can I be a vampire too? 😂

[@robertschnobert9090]

I don't worry about infrastructure. If it gets too bad you can always add another lane to a highway. Simple, efficient, inexpensive. 🌈🇺🇸

[@eggtarts286]

It's all fun and games until you realize those highways need maintenance too, and someone hasn't been paying the bill on filling those potholes. It kind of doesn't matter what type of infrastructure you build if you can't get it maintained.

[@MosesMatsepane]

I had a career that spanned over 10 years in rail, most of it in Product Development and R&D. The amount of Engineering and Science that exists in railways will blow your mind. It's a culmination of all fields of Engineering, Electrical/Electronic/Computer, Mechanical/Metallurgy, Civil, Process/Industrial and Chemical. There were also Mathematicians and Physicists. There were so many brilliant minds working together to solve complex problems and keeping trains running smoothly.

[@gyrateful]

Geology too.

[@JO-df3ob]

Wow, thank you for your work!

[@mickeyslaven]

O’ playing you

[@ey3796]

Could you please explain the part where they angle the rails before pouring the liquid metal? What goes wrong if you keep the rails flat on the ground? Thank you

[@MH-ev3wr]

Mechanical engineer here - this video was INCREDIBLE! You meld the theoretical with the real world so well it's just awesome. Showing the actual graph of the test sample and seeing the fracture was soo cool. Took me right back to university days. I wish we had these types of videos to see when I was in university - would have made me even more excited about science than I already was.

[@ey3796]

Could you please explain the part where they angle the rails before pouring the liquid metal? What goes wrong if you keep the rails flat on the ground? Thank you

[@KaiHenningsen]

There is actually another kind of joint for rails that does not produce the ta-tack sound. The idea is fairly simple: you don't cut rails at a right angle, but at a very sharp angle. As a result, at the joint, one rail becomes slowly thinner, and the next rail becomes slowly thicker, and there is no gap for the wheel to fall into. This is sometimes used as an expansion joint for high-speed rail.

[@j_13]

happy new year🎉

[@Twofrogsonecup]

Happy new year 🎊🎊🎊🎊

[@jimmy_nut2908]

evil new year 😈

[@samson5erb312]

Happy new year!

[@Temo-f5d]

happy new year 🎉

[@therewarden9759]

Happy new year!

[@3d-eden978]

I love these dirty jobs style videos. It shows how complex seemingly simple jobs are and how much skill you need.

[@mernokimuvek]

Why is it a dirty job? Are they working on the sewage system?

[@3d-eden978]

@@mernokimuvek I am refering to the old program of Mike Rowe where he takes on dirty, difficult or dangerous jobs.

[@kaspervestergaard2383]

@@mernokimuvek No if you watch the video it's about rails.

[@Influfferious]

Worked for the BVG (Berlin metro and transport service) And welding these, one after another, in the underground tunnels was the second sweatiest job I have ever done. Somehow repairing the abrasion was even worse (by welding extra material ontop of the track to repair dents because you had to heat up the entire length of track around the weld to get it to not bend and stick properly. I can still remember the sensation of my shirt becoming part of my back through sweat osmosis.

[@emilyrln]

If welding in a tunnel only ranked second, what was the sweatiest job you've ever done?? 😅

[@aadarshsaraf7959]

What was the first??

[@TheKnaeckebrot]

​@@emilyrln Barkeeper at Berghain? :P

[@yunis_fritz]

Danke, dass du das dennoch gemacht hast. Infrastruktur ist fast so wichtig, wie die Facharbeiter, die sie am laufen halten.

[@WolfenReads]

My stepdad works there too :D as an Electric/welding engineer. really interesting stuff

[@bobbates7343]

As a retired long haul truck driver who used to haul things from California USA to Toronto Canada. I saw many many trains that were hauling what most people call shipping containers. I always came away thinking that my hauling some form of vegetation all that way was silly . The trains should be able to make the trip fast enough to handle the food being moved. Now it was not just the speed of the train that was the problem but the speed at which the shipping containers were lifted off the train and put on the truck that takes the goods to what is sort of the final place. That went fast sort of . The driver of the truck had to quickly move the truck into the right spot then pull away rather quickly but the line up to get into that part of the system was sometimes hours long. That has to be fixed. Then I would have no problem with things that are being moved from one side of North America almost all the way to the other side all being done by rail. Such a huge savings. Still millions of trucks and drivers but we would all be going on shorter trips and most often home at night

[@conanobrennan53]

capitalism is a big part of it. Railroads can often charge too much to make it worth it. A fully loaded freight train takes about 300 trucks worth of cargo but they can be slower. There was a refrigerated fruit train that ran from CA central Valley across the country to east coast that i used to see a lot when I was working in CA central valley.

[@dh5341]

you're talking intermodal trains and they usually are the fastest and usually get priority over other mixed freight trains. sounds like you were at a port where there's thousands of containers. that said RRs know once they get your product you're at their mercy. they're also greedy knowing a railcar can carry over 100 tons and can replace many trucks and charge $ accordingly. they didn't get the reputation of robber barons for nothing. they lost a lot of business to trucking by raising prices and fuel charges etc after spending years to get trucks off the road.

[@casmatt99]

As a transit nerd, this is literally and figuratively the most metal thing I've seen.

[@orangejjay]

😂😂❤

[@vary1143]

Why would u have that as smth ur nerdy for 😂😂

[@kaiperdaens7670]

HUUUGE respect for the people that do this every day, I don't think I need to explain why.

[@Hans-Yolo]

We are a small Blacksmith Shop here in Austria but from time to time we make these Wedges für the Austrian Rail Company and in the past also for Goldschmidt Austria and other Companies that do this weldings. Nice to see how these guys work with them

[@munyabrownn]

I run a railroad maintenance company in Zimbabwe. with plans to expand into most of the region. Traveling Czech Republic and Germany sometime this year 2nd quarter. I would love to know more about your shop and if we can also become a customer for some consumables you make

[@jamesfoo8999]

This is an incredibly laborious and time consuming task, with an insane amount of manual tools and fiddly manual work. And every mould is a single use. All for every joint. I can't believe there's not a more modern and easy/faster way to do this. Great video 👍

[@HilariBarbae]

3:56, you can clearly see he's pro, hands free smoking during work, never seen anyone more pro in my life

[@PiqueiroQueDoa20Reais]

Smoking while welding with oxy-acetylene.

[@walderlopes3372]

I noticed that instantly, too. Brother out there, in the night, middle of nowhere, heavy machinery around, cigarette on his mouth. That's a pro.

[@squidcaps4308]

Pro's use short, stubby cigarette holders. You can point it at the side, away from your nose and you can plug the end with your tongue so you can breathe without constantly drawing smoke. When i smoked and worked, that little stubby holder was god send, you can easily keep working without eyes and nose stinging, and since pro's also roll their own cigarrette's, they will extinguish on their own. So, if you work and smoke, get one of those stubby holders.

[@lenzelot983]

Bro probably lights his cigarette on the Thermite Reaktion

[@SolarCookingGermany]

@lenzelot983 😄

[@PietriGuitars]

@07:55 the guy with a cig hanging from his lip means he's a pro at his craft!

[@dirkhartel7288]

I saw it and i knew i had to come to the comments

[@Alex-ng1ts]

Its crazy how perfectly accurate everything has to be

[@paulhatcher6406]

Thinking about this problem actually helped me forget all the silly troubles I had today. Thank you all

[@sebw.4939]

Great to have you folks here in Germany! Have a great new year! 🇩🇪🇺🇸

[@nerine4188]

This channel has became what Discovery Channel was for me when I was a kid, and I love it.

[@lucyfer7748]

In some places (Belgium), we use diagonally cut rails (lengthwise), that will expand one half next to the other. Allows for expansion without risks of derailing or buckling.

[@analoghardwaretops3976]

Even I was wondering why the technology did not improve from the rt. angle cut to the diagonal cut..... also the two parallel rail welds must be staggered by at least half the length between the two axles(front/rear).

[@stevecav2963]

I have worked on railway for 30 years and seen hundreds of welds being droped but to see it through the glass was amazing brilliant Well done and thanks for that👍

[@AalapShah12297]

19:02 "North Korea" Lmao

[@quinnjackson9252]

Haha I love it!

[@jari-0815]

They exist since 1895, so very likely that they had trade relationships also back then (before the embargo)

[@Elkadetodd]

The question was "viewers riding on his welded tracks". No internet, no viewers, so they aren't part of the sample set.

[@AlexTurpin]

Surely they're not watching Veritasium videos though, as the context implies

[@Aedelt115]

8:21 working with Germans in technical fields, I see that look daily. The look of, "Are you sure? You're not saying it like you're sure".

[@lucakun3455]

as a german in a technical field, you sure about that?

[@dicktiionary]

As one of my German friends often says to me "Do you know it, or do you only think it"

[@yunis_fritz]

The way Derek said it I'd have given him a double of that look xD

[@allliabdull6100]

In Germany we say "Sicher?" and I think its beautyful

[@rsage_]

Loved the choice in editing where you showed what you were learning to do while simultaneously showing the professionals do it on the field. It gives a great contrast of real world vs controlled environment. Also, @23:00 Rearden Steel would have never broken LOL.

[@Asrlex95]

All those night-time shots of the operators building the rails went SO HARD. Great filming

[@Fony_T]

As Railroad Technician it makes incredibily happy seeing veritasium at the fields that i operate at a daily basis. Seeing you try all the steps by yourself and get every knowledge behind the things you do is refreshing. I work with a lot of welders and youre right, these guys make it look like its an easy job. The scientific background and the seettrough weld was someting i always wanted to see. The Camera handled that exposure problem very well. Cant wait for the next Part!

[@conanobrennan53]

welding is probably the most physically demanding job on the railroads. Between thermite welding, grinding and then manganese steel welding on frogs those guys beat their bodies up.

[@ElChus]

I've been studying all this christmas to get cerfified as a Railway Traffic Regulator and your video was the best gift possible to start this new year. Thanks and happy new year! 🎉

[@cobble616]

This really gave me a new appreciation for rails, the fact that this whole process is repeated for every. single. joint. is just crazy

[@plica06]

Did they say "every single joint"?

[@ArmandMaree]

Not every single joint, most joints done in the field yes. A large amount of joints would also be done using a process called Flash Butt Welding

[@BelialTnTn]

@@plica06 I mean the one I just smoked didn't need all that.

[@brqxton8974]

They do have dedicated train cars that do this welding without all this hassle...

[@cobble616]

@@ArmandMaree ah ok, still pretty cool though

[@TheREBwater]

I just happened to notice what looked like this process of track repair using thermite. Very interesting and exciting for me. Though it was in full daylight, the molten brightness of the flowing metal was uncomfortable to view directly. Very cool (so to speak) to be able to witness this. I think no one else driving by the area knew what was being done. But I had seen a different video demonstrating this a year or so earlier, so I suspected what was in progress. Glad I stopped and stayed out of their way.

[@conanobrennan53]

definitely shouldn't stare at thermite pour directly without correct shaded lenses. You will do damage to your eyes

[@DerOrso]

I get to see them do this every couple of years at night on the tram line right outside my window. Every couple of years they have to replace the tracks from the downhill curve leading to the tram stop, which receives a lot of stress from the trams braking and being in the curve. But I've never seen such a detailed description of exactly what they are doing ever step of the way, and exactly what and all the consequences of deviation are. Absolutely fascinating. Thank you!

[@ravipalat2869]

This video really makes me appreciate how much skilled labor goes into our infrastruture. 150 of these welds a night is an incredible pace

[@thecaneater]

14:15 I love the Old Timer just taking a drag in the midst of what looks like Hell.

[@Rob-ji7fx]

You think that guys an old timer? Lol

[@schinbone0]

I was a locomotive engineer/train driver for the railroad for 30 years and my best friend was a thermite welding supervisor. I had the chance to spend a couple of days with his gang and it was really interesting. Not sure if the video mentioned it but the railroads finally adopted this because of derailments and maintenance costs of jointed rail. For the record the top of the rail is rounded, they call it the ball. When you match that with the angled wheels, it works like a differential when going around a curve.

[@aayushsood5983]

As a Metallurgist it was really fascinating to watch. I really appreciate the effort put up by the Veritasium TEAM. Kudos to you guys 🙌

[@MatthewKennedy-t1g]

Derek, your video output for the last few months has been insane. Although I don’t expect it to continue at this rate, I want to thank you for giving me so much content to enjoy and share with my friends and family. Can’t wait to see what you have for us in 2025!

[@NewYorkCentralHudson]

I like trains, and science. This video being made is a big win for me.

[@jishan6992]

I love the fact despite derek being an American, he mainly uses metric measurements in his videos as a true science guy, i appreciate it so much

[@laraleo6412]

He was born in Australia and grew up in Canada...😂

[@jishan6992]

@laraleo6412 ahh that explains it, but i do find it funny that all the hardcore science labs in U.S use metric system despite everything

[@conanobrennan53]

It's also going to be the defined measurements for thermite weld manufacturer's instructions. They have similar measurements in USA in US Imperial measurements. A lot of the measurements are in thousandths of an inch.

[@JustMeBlindFreddy]

if +he "mainly uses metric then he is no science guy

[@jishan6992]

@JustMeBlindFreddy aight american

[@rarestarball]

Happy new year!!

[@JFirn86Q]

That see-through half section was amazing... had to play that frame by frame over and over. Wild how it flows and why it's all shaped like that and trying to analyze it. Really cool seeing how it's done in the field as well as a controlled set up, and the difference between them. Remarkable how professionals develop such a fine technique to do it quickly & perfectly compared to the controlled set up.

[@hoperp1951]

Amazing, cannot wait for part 3 :) I worked in the UK Titanium industry for 40 years, I came across a sort of "thermite" type reaction with Titanium a few times. Titanium has a high affinity for Oxygen and Hydrogen in particular when it is in a finely divided/fine form. So Titanium fines and dust from machining operations can build up on machines like lathes etc. Should you also machine Steel then the fines of Titanium and Steel can mix unless you are very careful to clean the machine down after each different material. A mix of Titanium and Steel fines can spontaneously combust. As the Steel fines rust, the Titanium which has a greater affinity for Oxygen than Iron will pull the Oxygen from the rust, a chemical reaction occurs which raises the temperature until it catches fire. I would guess it is a long slow process to start the reaction, but I came across this a couple of times "in the wild" so to speak where machining swarf and fines from mixed materials were dumped aside and caught fire spontaneuosly. Could be a nice little research project for someone and perhaps a useful commercial process for something at the end.

[@mmorris2830]

That's how most fires that destroy aluminum fab/manufacturing plants start. Fine aluminum dust and random chunks of iron that has rusted. Eventually, the right ratio of FeO+Al occurs, and it starts getting hot

[@hoperp1951]

@@mmorris2830 Ah yes, I am sure lots of such things happen. None of our "experts" aware of the Titanium and Rusty Steel turnings reactions, came as a bit of a shock, though the spontaneous combustion of Titanium Grinding fines, even when wet was a well known thing and resulted in having to store the stuff in 45 gallon drums under water prior to regular disposals.

[@CrimFerret]

I don't think I'd want to be anywhere near a titanium fire.

[@ConwayBob]

Thanks for explaining that so clearly. Having grown up in the clickety-clack age, I found this fascinating.

[@PmBoyle]

I gave myself metal fever making thermite when I was about 14, bought everything off ebay bar a respirator.

[@CableWrestler]

I love how you reference other videos and give praise to other creators. The cherry on the top is the link in the description.

[@Gerald_Hunker]

I knew most of the things mentioned in the video, but I never could quite get over the problem of expansion in summer and contraction in winter. No-one ever explained it to me in such a comprehensive and understandable way. Now I finally understand the physics in toto. Thank you for the insight, and thanks to Goldschmidt for the rare footage! Amazing video!

[@chuntguntley8771]

The vertical and horizontal alignment bit killed me lol. I'm dying laughing. The delivery of your semi-frustration is palpable.

[@bebobism]

I have much respect for the guys doing the field work at night over and over again. This is a hard job physically and the hours put you slightly of set to the rest of working people around you , making socializing more difficult also. 💪

[@wiLdchiLd2k]

Its not that hard at all... and they get paid very well here in Germany. Its more like a dumb and boring job... but there is way more to Oberbauschweißen than SKV-Welding. Thermit is just the starting point as an Oberbauschweißer.

[@wtfdude1830]

@@wiLdchiLd2k Then can you do it and post a video about it if you say it's dumb, boring and not hard at all

[@Asto508]

@@wtfdude1830I think it's really not that exciting anymore after you done it a few times. It's a repetitive work, that's why you see them smoking while doing it. Physically hard, but mentally must be really boring.

[@Jarandjar]

@@Asto508 Once you beat the barrier of 'physically hard' it definitely just becomes boring and monotonous.

[@wtfdude1830]

@@Asto508 Yeah perhaps you are right, just like other job, its getting boring

[@neneaniket]

03:54 - The welder is casually smoking while welding! Epic!

[@Devantejah]

It's to filter out any noxious gasses from the welding process, normal procedure.

[@lucasb6207]

It's the same for guys working on building streets with tarmac ;-)

[@andersnilsson973]

It is to be absolutely sure he gets ammonia.

[@Paco1337]

He is from Balkan I can feel it 🤣

[@TucsonDude]

@@andersnilsson973 Not to be confused with pneumonia.

[@kaeseblock1362]

Very interesting. Thanks a lot and greetings from Germany 🇩🇪

[@user-wg1gd5gg7s]

11 year mechanical design engineer here; a good and fun video but I don't think the final explanation really makes it click for most people. It's actually really intuitive if you think about it in principle rather than mathematical terms. When a piece of metal is heated up (energy put into it) it wants to increase in volume to balance out. It will take the path of least resistance. That might mean increasing in length, bending or lifting/twisting. If you take away all of it's options to do so besides increasing in size at the cross section of it's shape (growing outwards sideways and upwards) then that is what it will do. If all the rails do that it's fine because the train to rail connection has enough tolerance/play to account for it. Everything beyond that is very specific to making the exact rail and type compatible with the environmental conditions etc such that it doesn't fail during that process (can withstand the stress acquired from the strain of outwards growth).

[@billyraybar]

Thanks for the intuitive explanation

[@user-wg1gd5gg7s]

​@@billyraybarGlad it helped my friend.

[@QuintBUILDs]

Hey Derek, would you double check the explanation at 5:42 on why the rails must be angled up? Since the top of the weld gets poured last it will be the last to cool. If the bottom indeed cools first (as depicted in the animation at 21:25 ) it would solidify and shrink, squeezing and deforming the upper more malleable portion together. Then as the top solidifies and shrinks it acts like a hinge around the already solid bottom portion. Thus if it weren't angled up already it would "hinge" below level. The explanation "since there's more metal at the top" makes it sound like if the weld surfaces were parallel there would be no distortion because the same amount of metal is everywhere and the shrink would be perfectly even.

[@XxZeldaxXXxLinkxX]

Yes, I was quite unsatisfied with Derek's explanation as well. "Since there's more metal on top..." Well of course it is thicker on top, you put it there, silly.

[@eliasandersson8236]

@@XxZeldaxXXxLinkxX maybe he means on the rail, since its an I-beam, but then that would also be true on the bottom so idk

[@tristanbrown6954]

Sounded like an explanation from chat gpt to me

[@bradleysampson8230]

I also didn’t understand this part. If the rails weren’t angled at all, wouldn’t the even amount of metal from top to bottom pull them in evenly?

[@iandaniel2153]

@@XxZeldaxXXxLinkxX `yep! .... more metal on the top ... ergo greater mass on the top than t/o rest of the sectioned rail.

[@DrCranberry]

Seeing you do a tensile test as a welder was very neat! And they ARE correct. In many cases when we do tensile tests, a perfect weld would break on either SIDE of the weld, not in the middle of the weld. Because the weld itself, in many cases is ALWAYS stronger than the base material. Which is why we add filler metals and the like back in. But even if you didnt add filler metals, the weld should still keep the properties OF the base metal, and will only break in the Heat Affected Zone, which is why it's important to keep this zone small (especially when doing TIG welds). The smaller the zone, the less chance of failure down the line due to stresses.

[@ColderBacon]

My favorite thing about this channel is no matter how big you get, you always remain quality and informative. I see too many creators sell out and start getting sloppy. They do bigger and flashier things as they grow, but loose that informative quality these videos are made to present. Veritasium will always be a favorite channel of mine. ❤

[@levileavelle2446]

Mark rober is a prime example.

[@Chuycabra]

I think my favorite thing is seeing these people who have been in their field for years get excited over seeing what they do daily, just in a different way! You don't often get to see passion like that!

[@DeVallaR]

Bro at 22:48 straight up a giant! Thank you rail testing man!

[@psychologicalprojectionist]

Wow, this is the kind of exacting, disciplined and painstaking work we take for granted, which ultimately improves all our lives.

[@A.Filthy.Casual]

26:47 NEXT?!

[@EyesOn-Me]

Let's GOOOOOO!

[@CandC68]

My dad would have been fascinated. I was. He passed away 60 years ago. He started his railroad connection in Schenectady, NY as a draftsman. Creating blueprints of steam engine parts. Then got into sales and sold trains for the General Motors Electromovtive Division. When the steam engine he first sold was finally taken out of service, he was given the head light and bell. Now lost to history. As a kid I always thought it would be great to be a gandy dancer, working the rails. But, never got into it. Life is what happens while you're making other plans. I guess these rail welders are the modern gandy dancers. Hats off to you. Similar to the grinding machinery, my dad sold the first "track cleaner" machine. Now probably vastly improved or replaced.

[@Zippofanatic77outdoors]

I used to do this for a living. Worked for CN master welder. Hated the job but loved the wildlife

[@Dp270]

How much did you get paid?

[@ryandavis7390]

Why did you hate it?

[@chronovore7234]

@@Dp270 $50k to $80k depending on experience and which company you land a job with.

[@conanobrennan53]

@@ryandavis7390 physically demanding job, direct managers that act like tyrants, bad coworkers, and if you're on a travelling gang you're on the road constantly. UPRR would have compressed half crews that worked 7 or 8 days on and then 6 or 7 days off but your travel home was on you and could be brutal if you're travelling from some of the more remote areas on the system.

[@ElectricFS]

Great to see the ingenuity of some engineer 100 years ago still has such a huge and lasting impact today. Shoutout to the Elektro Thermit team to give access and such insights into their world! Grüße nach Halle

[@davienjoloma4715]

Happy new year, Veritasium

[@gunsmither]

Great video! I have used Thermite welding many times for connecting copper grounding cable to ground rods, and when grounding steel beams in buildings. The process was called Cad Welding. In 1968, as a 1st year apprentice electrician, the first time I ever worked with the process scared the daylights out of me! The graphite molds were used over and over again, and would leak molten metal when worn. Ouch! .Had to be really careful, especially when crawling along steel beams on large buildings. Thanks for making this video! Joe

[@craZduck19]

Love a video that combines the concepts of microstructure in steel and Stefan-Boltzmann law. Would have loved it even more if you let the people know about the pearlier structure of the steel that was slowly cooled

[@JerryRigEverything]

Really cool video!

[@veritasium]

Thank you for watching, glad you enjoyed it!

[@astrogamer158]

As someone obsessed with thermite, I'm so happy for this mini series on it.

[@spinnymathingy3149]

Personally, I’m obsessed with chocolate

[@muhammadumarqasim6809]

This weld preparation science is much similar to what we do in pipe welding. Would love to see if you could some videos on engineering challenges in oil and gas industry.

[@sapelesteve]

Now that is a really incredible process related to Thermite and rail construction! It looks like Veritasium will soon have 17 Million subscribers! 👍👍💥💥

[@Damian_CS2]

Shoutout to Grady! I love Practical Engineering

[@aashleyjofina1565]

happy new year sir , i am 15 year old and love your content sir , keep uploding more about mathematics the visual explanation , science , how everything works , thank you

[@bobgroce9142]

Outstanding documentation of the process of using thermite reactions to weld railroad into a seamless track. As a high school chemistry teacher I often demonstrated the "thermite reaction" for my students - reacting powdered Al2O3 with Fe2O3 and a source of heat from a chemical reaction between KClO3 and imbedded lengths of Mg ribbon. Concentrated H2SO4 would begin the heat generation process. The two powders were blended and placed into double clay flower pots inside an iron ring stand placed inside a metal bucket filled with sand. As the chemical reaction ignited the Mg ribbon inserted into the powdered mixture, the heat would initiate the reaction between the two powders, producing the molten iron which would flow through the hole in the bottom of the flower pots into the sand. My students loved to observe the heat and bright light of the molten iron, as it flowed from the bottom of the flower pot. I would always remind them the very same reactions were used to weld railroad segments together. Bob G

[@grougrouhh1727]

24:27 is what i wanted to know

[@newbie4789]

Exactly. I had it in my school textbook that the gap is for expansion. I'm used to the tuduk tuduk... Tuduk tuduk sound of a train

[@D3nn1s]

Its not only that, but afaik every welded rail cant go in a perfectly straight line. Since its constantly curving left and right the railway can expand by pushing itself into slightly more of a S pattern, while in winter it can slightly straighten itself out.

[@daveash9572]

Wish I'd read the comments before watching. I just came here to post exactly this.

[@daveash9572]

Actually, the info at 26:29 is perhaps the key bit of info.

[@McVaio]

Thank you!

[@magicprocess_360]

Having worked as a foreman on rail thermite crews for about six years, I’ve got to say, this video is fantastic! They should seriously consider including it in our training sessions. While we do cover the handbook and go through the dos and don’ts, we often skim over the reasoning behind those guidelines. It’s great to see the detailed breakdown here. I also noticed some interesting variations in procedures-for example, after shearing the weld, we use an insulating jacket to slow down the cooling even more. Another thing we do is grind the mold halves against the rail side-to-side during fitting to ensure a tight seal, especially on older, worn tracks. This video really captures the nuances, and I’m excited to see what’s next!

[@ironman4do]

This was posted by someone else 4 days before you posted this: I was a foreman on rail thermite crews for about 6 years, and this video is awesome! They need to start showing this video in our training classes. We get the handbook and go over what we should/shouldn't do, but gloss over a lot of 'why' we should/shouldn't do these things. It's also interesting to see the little differences in welding procedures, one I noticed was that after we shear the weld, we put an insulating jacket over the rail to slow the cooling process even further. Another is when first fitting the two halves of the mold to the rail, we hold the molds tight to the rail and grind them against eachother side to side to help get a tight seam. Not as necessary on new rail, but essential on old worn-out tracks. Looking forward to the next video! Looks familiar, doesn't it? I have two fingers for you. The first is a 👎, and the second is🖕for being a copycat.

[@shakeelali20]

19:07 "Finally they will ride above our welds" Almost sounds like a threat in a German accent.

[@Ryan-kf7of]

The production really feels it came through in this video. Moments like you saying it's exhausting then panning to the guy behind having no issues wasn't only funny but really humanises you and is more engaging. Not only that it's a nice break from LEARN LEARN LEARN. I love learning but I also like to joke while doing it.

[@calculusinanutshell]

Happy new year derek ❤

[@tabletopstudios3550]

Finally! Part two! Thermite is definitely a great new years firework.

[@Kev2500]

Watching this after the New Year’s party makes a perfect end for the night

[@mohnchichi]

When you heard "rail" and "line" amidst the new years cheering, I don't think this video was what your friends were calling for.