HUGE vs. TINY drive wheels - Why? | Railroad 101

[@brookspotts9312]

I remember the first week learning about gear ratios in robotics . It became a hilarious and quickly degrading topic as my classmates and I realized how little we understood about all the factors that contributed to motion. Great video ❤️

[@markst.germain9286]

Bedford Express FRC 1023 Bionic broncos FTC 6079

[@whisper9539]

It is a good example of easy to understand what it does but now how it works

[@traininthebutt7215]

Angelbotics 1339

[@Hyce777]

@@markst.germain9286 Team Audacity 4682. :)

[@brookspotts9312]

326 Extreme Eagles 🤘

[@DelayInBlockProductions]

This man knows so much about steam that a locomotive was named after him. It's called a Hyceler.

[@Hyce777]

:P Something like that! Cheers mate :)

[@Coaster_F59PHI]

Ya mean the Heisler locomotive?

[@greggorytame6672]

good god yes! I can finally send this to people for a quick explanation! all of the locomotive performance in steam and steel is based on the actual physical attributes of the engines. and so many times people go "but.. why can't you make this faster? why can't you make this one stronger?" Like, my brother in christ, I'd have to remodel the entire running gear for that!

[@CMDRSweeper]

Easy fix! Quick disconnecting running gear! : D

[@phantomkate6]

"We tried painting racing stripes on it but were disappointed when that didn't work. Well, I'm out of ideas." Then wait for their reactions. 😂

[@arch9enius]

@@phantomkate6 Like the LMS did with their Coronations...

[@commandoepsilon4664]

@@phantomkate6 Racing stripes?!? Well there's your problem, try painting it red. Everyone know red one go faster.

[@Combes_]

​@@commandoepsilon4664Do both!

[@gherkinisgreat]

For true speed you need the GWR Hurricane with it's 10ft driving wheels

[@ajaxengineco]

'We don't need adhesion! Fuck it, put the boiler on a tender frame, who cares?' - Brunel, probably.

[@atshinkansen7439]

So many British single driver locomotives compensated by having those wheels at such huge proportions. It was almost a trademark feature of these locomotives.

[@davidty2006]

ah yes from when everything that was passenger related was a 2-2-2 and 2 of the wheels were big chonkers.

[@stanfischer6175]

What has always intrigued me were the ATSF 5001 and 5011 classes, freight engines with passenger size 74" wheels.

[@Hyce777]

Fast freight is a thing! :)

[@christopherspringer2764]

I used to think that narrow gauge engines were much smaller just because the track was smaller, until I read about South African Railway's Red Devil. A 3' 6" gauge 520,000 pound 4-8-4 with 60-inch drivers, that could do over 80 mph and pull a serious consist of freight. A very fascinating video, and at last a second opinion on locomotive mechanics for all of my friends who think I'm crazy! Love it!

[@masteristscalerailroadmodels]

The biggest Cape gauge, AKA 3'6" locomotive driving wheels wheels I am aware of are on Japanese C61 and C62 locomotives, measuring 1750mm or roughly 69" upload.wikimedia.org/wikipedia/commons/6/6b/JNR-C61-2.jpg

[@jacksales9342]

The wide angle shots with you standing right next to the locomotives gives such a good sense of scale! I really had no idea how massive these things are until I saw you next to them and it's really fun to see.

[@Stooltoad5017]

I like seeing some of the inoperable locomotives at the Museum, 20, 346, and 491 get a lot of well deserved attention for being in operating condition. However, I personally still like the static display locomotives even if it isn’t possible to run them at the museum.

[@oriontaylor]

New York Central’s L-3 Mohawks were intended for a lot of mixed traffic work and thus were fitted with 69-inch drivers, but built with the capability to have 72-inch drivers fitted if the need arose for higher speed demands. As it happened, the need wasn’t there, and the class leader (only one fitted with larger drivers) was later swapped out for standard 69-inch.

[@michaelasbury7121]

The same concept can be applied to internal combustion engines. Some inline sixes, like the flathead six found in the Dodge M37, have a lower power band than, for example, a 2JZ. The reason for that is because the Dodge's crank throw is longer than the 2JZ. That means you can get more low-end torque, but not the top-end performance of the 2JZ.

[@kornaros96]

Of course with variable valve timing and lift you can stretch that band

[@dustinbrueggemann1875]

@@kornaros96 but you can't effectively change where that band is *centered* without making a lot of other changes to the engine itself, and that's where gearing has to step in

[@shoryuag]

Hmm…. If the Dodge T245 makes indeed more low-end power than the 2JZ, it’s because the T245 has more displacement, a smaller cam(s), and smaller ports. The longer stroke equals more low-end power thing is a myth. Likewise the reason the 2JZ makes more midrange and top-end power (potentially low-end power, too) is because it flows more air and can therefore process more fuel, creating higher cylinder pressure, leading to more power. The only question is whether the larger ports and cams of the 2JZ offset its ability to create higher cylinder pressure enough at a very low rpm to make your statement about the low-end power true on its own.

[@shoryuag]

@@dustinbrueggemann1875It’s wild that the gearing all comes from the wheel size on these steam locomotives. Makes sense; still wild.

[@geoffmooregm]

​@@shoryuagAlthough displacement and compression are the biggest factors in determining torque, an under-square engine does tend to favor a low speed torque/power application vs. an over-square one. However, I do agree that these traits are over embellished online. People love to bench race two motors with the same displacement and then you look at the specs and there is like a 2mm difference in crank stroke. The same happens with I6 motors. People love to say they make more torque than a V8 of the same size. But in reality, they never did. But because they are often grossly under-square they usually cannot spin fast enough to make big power numbers so they usually end up in trucks where they rarely spin past 4000 rpm and are focused on low end power and torque. I am not saying that's a bad thing I love I6 motors and there are exceptions to the rule (Ford Barra, GM Atlas, Toyota, Nissan, BMW all have examples) but it's just a funny myth that never goes away.

[@CDROM-lq9iz]

Hey it's me again. When you started talking about gear ratios it reminded me of a chart from one of locomotive service manuals. The manual in question was for an SD45 and it has a chart for top speeds. The gear ratios it mentioned for the D77 traction motor started at 62:15 and went to 57:20 and the top speed went from 65 to 95mph respectively. I know GE motors use different gear ratios starting at 74:18 but idk any others.

[@marktegrotenhuis]

This driver wheel size thing is something I already knew. In the Netherlands we mostly look at German steamlocomotives and there the differences in wheel diameters are quite big. Big wheels are for speed, the smaller ones for power. That's why a BR 01 locomotive (used for long distance passenger trains) has about 79" drivers and a BR 52 locomotive (used for freight trains) has about 55" drivers.

[@Hyce777]

Aye, it's fairly common knowledge amongst many of us, I moreso wanted to point out how stroke relates to the crank and it's not as simple as just the wheel size. Cheers! :)

[@marktegrotenhuis]

@@Hyce777 True, but I think it's also quite logical to think that the crank on bigger wheels is always shorter in relation to the wheel than on smaller wheels. Because if it would be the same you would need way longer cilinders for those big wheels in order to get the piston to make the needed stroke length. 😉

[@twistieman1078]

Good for you, this video taught me a lot however.

[@catfish552]

I'm really enjoying the cuts to a wide shot you've had here and in the tunnel motor video. It gives a sense of scale to the locomotives that even a shot of standing next to the towering drive wheels doesn't provide.

[@JanTonovski]

I recently went to see a DRG Class 18, those drivers where absolutely huge at 2,1 meters. However, the crank pin was very close to the center. This video explains very well why that was!

[@Der_Yoloist]

I love how you teach people with that amount of passion! it really drives not only trains but me also-.

[@peregrina7701]

Hyce, friend, I'm now on my second watch-through with a pencil and the tractive effort equation in front of me. I'm trying to derive the equation now. This is alarmingly well-timed with the Discord discussion of the proposed Berkshire the silly Midland Terminal wanted. I'm still not sure if they wanted a fast locomotive, a strong one, or both (which seems like a poor answer to an optimization problem). Thank you for the video. Always love seeing the Museum engines and learning something.

[@Hyce777]

I'm glad! A little hint about the tractive effort equation's derivation is that there's a little bit of cancellation factor using the diameter of the wheel in the calculation vs the area of the piston, and what's left over being rolled into our 0.85 K factor we multiply the whole thing by. At least if I'm remembering right, lol! :)

[@peregrina7701]

@@Hyce777 I got embarrassingly hung up on the piston size being a diameter and not a radius until I remembered the locomotive comes with _two_ pistons, lol!! some math later and everything worked except that I got K= pi/2 which is not 0.85. Is something else hiding in that K factor? PS. I believe this is the first time I have ever _voluntarily_ derived an equation. What have you done to my poor braincell. Lol.

[@theimaginationstation1899]

@theimaginationstation1899 The K factor is simply mean effective pressure "MEP" as experienced on the working face of the piston. K = 0.85 was adopted by the American Association of Master Mechanics in the late 19th century as being a typical MEP at start up as shown by numerous indicator card tests. The addition of MEP into the equation is the only change to the equation since its publication, in English at least, in 1836. In New Zealand we used K = 0.8. But for North American locomotives up to Super Power K = 0.85 is a safe bet. K can and does equal other numbers when limited cut off is used for instance. When a locomotive out performs its rated tractive effort it is because its MEP is higher than 0.85. With superheated steam being more fluid and late steam designs being more refined in terms of steam passages it isn't unusual to find examples of rated TE being exceeded. There is unfortunately a very unhelpful pdf online that goes into lever and torque and what not - and imagines K as everything but MEP. It also imagines driver height instead of driver diameter, but that's another story and has much to do with the TE equation being counter intuitive at first glance. de Pambour (1836) is available on Google Books for free download. Johnson (1942) is available for view from Hathi Trust. Both reward the effort. @peregrina7701 @@Hyce777

[@petergrhill]

The BR(British Railways) class 9F 2-10-0 had 5 foot wheels, for heavy freight working, but were clocked up to 90 mph on some passenger trains.

[@dshack4689]

Fantastic explanation, I'd always wondered why the diesels and the roundhouses were somehow mutually-exclusive eras, and it turns out I hadn't understood the scalability of the diesel power versus the locked-in wheel-size-to-torque-ratio of the steam engines. Eye opening for something that I thought I already understood, thankyou Hyce!!

[@weylinwest9505]

It was very nice to see #4455 at the end of the video! Reminds me of her (brother/sister?) #4466 at the California Railroad Museum. I have an old railroad VHS video of when it ran (probably pre-1999).

[@TheAsianGmer]

I remember when I visited to see 5629 when I was younger and I was in absolute shock at how massive the overall size of the train. I stood next to the wheel base and it was almost a whole head taller than I was. I would love to see a train that gargantuan pulling a rake of coaches.

[@brad9529]

Its quite insane how much information there is to know about trains, every video i find interesting. I grew up with a dad that drove locomotives and i drove them myself as a kid with him in charge.

[@kennethfuller8347]

I've been a railfan for many years and only had a vague idea about the size of the drivers vs. tractive effort. Yes, I found your vid very enjoyable and informative. You presented it very well. Thanks, Hyce.

[@insylem]

Thanks for addressing the crank size. I've wondered about that for a while

[@lawrencequave7361]

Sorry. I just have to say it: In December of 1956 when I was 9 years old, Santa gave me a Marx brand electric train set. While my little train was pulled by a conventional steam-type locomotive, the box the train came in had a top that featured a beautifully detailed drawing of an EMD F9 diesel locomotive pulling a passenger train. The perspective of the drawing was exactly like that of the Rio Grande F9 shown at about 7:48 in this video. I instantly fell in love with that locomotive because of its beautiful curves, kind of like the Lockheed L-1049 Constellation airliner that went into service around 1950 or so. I traced that loc picture over and over again, totally fascinated by everything about the engine as I wondered 'what everything was for'. While aviation and aircraft eventually became my primary love, I never lost my love for trains and their locomotives in particular. And that explains why I have a beautiful HO gauge EMD F9 on display among my couple of dozen scale airplane models I have scattered about in my home office. Like the Constellation airplane, I think there is no locomotive that matches the beauty of the F9. (A note to the ladies: Men truly LOVE big, powerful machines like airplanes, trains, ships, etc., but the ones we seem to like the most are the ones that have nice curves. I wonder why.)

[@Tuckaway]

Very interesting, we don't normally think about the crank centre position on loco wheels. I also noticed that there were no flanges on the two middle wheels on 191 to allow it to cope with tight radius curves.

[@truckinman86]

After watching your video, I thought of an idea for a future video; perhaps discuss in detail the difference between an A-unit and a B-unit and perhaps show how a B-unit is controlled without an A unit.

[@therocinante3443]

Thanks to Hyce I've gotten into model railroading. Boy it isn't cheap as I thought but what a rewarding hobby! Thanks Hyce!

[@dinochanell42]

Good to see another steam locomotive component facts video from Hyce. Love your stuff and much love❤

[@patricksheary2219]

Hi Mark great explanation into the importance of wheel size and how it relates to speed and tractive effort. Also really liked the your main point about crank placement to wheel size ratio, force and speed. As well as the crank setting the piston stroke and what that all means. Fabulous details in this video. Speaking of details, really liked seeing 191 up close as you discuss it’s wheels, crank and all that. I really get an appreciation for the small size of the earliest locomotives, so amazing and, frankly beautiful. I stand at awe when seeing C.B.&Q. 5629 what a choo choo. To quote you it’s “super cool.” I’m always struck by how diverse and impressive the the rolling stock collection is at The CRRM. Well, Professor you give me much to contemplate with this latest 101 video. Learned so much! So many thanks for another well done episode and many cheers to you! 🎉

[@goodeye03]

Just wanted to say that I love your videos. I watch them via cable on TV and really can't comment on anything that way on my big TV. But thanks. I've been a rail fan since I was a child and even worked for Amtrak in the 90's. Best job I ever had.

[@paveloleynikov4715]

Another point with roundhouse - you need much less daily maintenance for diesels and electric locomotives, and it is much easier to make specific depot to work on specific types of units.

[@ajorsomething4935]

Though I am familiar with this concept already I think you should have explained in more detail. You mention that for a given wheel to cover a distance it takes a certain amount of rotations. That's why rotating at the same speed, a wheel with smaller diameter covers less distance than a larger wheel. Forgive me if I missed it but you didn't mention the reason steam locomotives don't simply rotate smaller wheels faster is because it creates balance and wear issues due to all of the moving mass in the valve gear and the side rods. Diesels don't have all of this extra stuff that needs to be balanced so they can rotate their wheels faster. Also, steam doesn't expand instantainiously, by reducing driving wheel size you increase piston speed and if you go fast enough the piston outruns the rate the steam expands at, and so it doesn't apply enough force to the piston to accelerate more. Answerong the question a viewer might have of "why can't they make a fast engine with small wheels so it can also haul large loads?" By the way, you didn't really mention that the reason smaller wheels for a given crank offset are more powerful is because the power of one stroke of the piston has to move the train over much less distance, since one stroke is 180 degrees of rotation, the power created in one stroke always has to be spread out over the distance the wheel rolls in 180 degrees. Horsepower is (torque x rpm)/5252 so torque value supplied by a given piston will create much more power over a distance if the piston works at a higher rpm (to a point, as I mentioned, steam can only expand at a finite rate).

[@SierraRailway]

One of the other benefits of the roundhouse and turntable combination was keeping shop space to a minimum while maximizing overall yard space. A turntable essentially acts as a single switch that services numerous tracks (hence the *round*house that typically accompanies it), while an ordinary turnout may only diverge two or three ways. This was especially critical for early smaller scale operations, where right of way acquisition costs were prohibitive and easements were sought instead. A comparison would be the size of the Jamestown Shops of the Sierra Railway compared to the East Ely complex of the Nevada Northern, significant difference in the amount of space needed and used while accommodating each railroad’s respective needs. When the diesels came along and railroads began to modernize and economize their operations, that’s when the roundhouse and turntable became obsolete, as just like the production line approach to manufacturing diesel locomotives, the goal was to bring them into the shop and get them back out as quickly as possible, at which point the roundhouse and turntable element became an impediment to speed and efficiency.

[@epicstormchaserswf]

Lovely explanation of driver sizes Hyce.

[@PanduPoluan]

Fascinating! Another aspect of steam locomotives I never knew! Thank you for this very educative video, good sir!

[@dennisk5818]

Always wondered about the size of drive wheels on one steam locomotive and another. You've been a fantastic instructor of railroading. The drive links and the piston timing is another area of interest. Saw a video from another author, who described the associations, timing and relationship of these.

[@railwayjade]

Thank you for the info on why Roundhouses in the US became obsolete, it never occured to me. In South Africa, we never really had roundhouses, most loco sheds were linear with parallel tracks. We also rarely had turntables, more in favour of triangles (wyes) and balloons.

[@carlenger9707]

I LOVE content like this dude, and I'm sure you enjoy talking about this stuff. Please keep it coming if you can! :)

[@mikeyanello3664]

Excellent video Hyce !!!

[@flycationstudios]

Great video, and I loved all the jump cuts and the way the video was put together. Plus the information was top notch. Didn't know that wheel size mattered in steam locomotives. Keep up the awesome work and content!!!

[@smokeebeefpv]

I'm in Colorado Springs. I'm gonna check your museum out soon. Thx for the videos.

[@andywomack3414]

I used to have an operators booklet for the F7, not that different from your F9. The top speed geared for passenger was 102 mph. At least that's what I remember. I haven't seen it for decades. Have short-time ratings been discussed?

[@MainlineThruTheRockies]

It’s also notable that the loss of passenger service made dedicated passenger engines obsolete. Back when passenger service was big, you’d have your passenger engines (E units, and sometimes F units) and then your freight engines (your GP7’s and SD9’s) You couldn’t just put anything on the front of the Zephyr (although often times railroads did anyways). Engines like 5771 were the D&RGW dedicated power for the Rio Grande Zephyr until 1983 when the service ended. When passenger service ended across all railroads, you didn’t need Passenger Power AND Freight Power, you just needed that freight power, which made operations even more simple. Last fun fact! 5771 had its own little shed near to Union Station in Denver for the Rio Grande Zephyr!

[@Funnyboiiiiiii]

This is the train version of schlatt change my mind

[@ravenamiir9340]

Always a great day when hyce posts

[@carltrotter7622]

Loving the guitar cover of "chatanooga choo choo". Thank you for your time covering this topic.

[@ohnoohyeah3205]

Have a beer with the fella from Technology Connections please. I'll buy.

[@johnathaneve1097]

I've been an avid train lover for years and I will tell you I didn't even know this information I thoroughly enjoyed the video and several other videos I have watched of yours your contribution to the knowledge of the train community is very appreciated keep making the videos I can't wait to see what else you come up with

[@JakeRoady-sf2ek]

I finally understand how the drivers effect the speed.

[@uncinarynin]

Now there are some steam locomotives from around 1900 or earlier that had absolutely huge driving wheels but didn't go all that fast. Later they could go faster with smaller wheels. I guess that they also made improvements that allowed higher piston speeds later on? Because that seems to be the limit ... you can't just turn the wheels faster, there's a limitation and so you need to make the wheels bigger to go faster.

[@edjones833]

I enjoy learning the little things (details) that I didn't know about railroading. What I learn from you I pass on and also implement in my modeling.

[@QuorkQTar]

Well explained once again =) With true electric traction it's similar, especially nowadays with three phase asynchronous AC motors. You can make it work with almost any wheel size for almost any speed. The ICE 4 e.g. has ridiculously small wheels for its 250/265 km/h top speed.

[@Stussmeister]

I remember learning about this concept (big wheels=speed, small wheels=power) some years ago, and came across an example of it when I saw two of Union Pacific's steam locomotives in Ogden, Utah. Living Legend #844 is used for passenger service and has large driving wheels to move the train as quickly as possible. Big Boy #4014 has smaller driving wheels, as it was designed to haul long freight trains.

[@captainkrazee7726]

Hyce, I’ve got a question. In some recordings of locomotives you can hear clanking noises along with the chuffing. I’ve noticed that it mostly occurs in engines with Walschearts and Baker valve gears. If you listen to videos of N&W 475 or what you’d be most familiar with (D&RG K class engines) you can hear clanking as the engine goes by. Why is that? And sorry if this question is poorly worded.

[@Hyce777]

The rods, depending on how recently they've been greased, will clunk around as they change direction. It's less noticeable on Stephenson gear engines because they just have less rods on the outside. :)

[@michaelkolano8686]

I assume its a case of shafts and bushings in joints having a bit of slop/tolerances that are just inevitable to have to some degree.

[@captainkrazee7726]

@@Hyce777 thanks for the info

[@MichiganPeatMoss]

Wow, aspects of railroading that I've never really thought about. Great video!

[@cadence4527]

Back in 1973, there was a train loaded with bombs that went kaboom while it was at the Roseville rail yard. Locals refer to it as the Roseville Explosion. At the time the rail yard still had its roundhouse and the explosion was started by a tinder box that had caught fire. So I thought, roundhouse + tinder box = steam powered engines, but my mom says there weren’t any steam engines involved. Why would diesel engines have tinder boxes? Could there have been steam engines still around at that time? Sadly, the Roseville Explosion is an event that doesn’t get a whole lot of attention.

[@UmoadoGaming]

This is a very helpful video. I knew that bigger drivers made you go faster, but I didn’t know about the crank position vs wheel size. Very interesting. Great video! Also, is that a recorded horn at 6:59 ? It just doesn’t sound normal.

[@Hyce777]

Wayside horn played over a speaker, rather than an actual locomotive horn. Good ear :)

[@UmoadoGaming]

@@Hyce777 Oh ok thanks!

[@akaBoG]

Very informative Mark.

[@theMG174]

Hyce, this was really interesting and makes sense as far as the need for the turntable.

[@crrm]

Good video Mark!

[@u2mister17]

My fist memory was holding my Mom's hand on the big wooden platform watching our steam engine train pulling up in Pittsburgh Pa. We traveled to Columbus to our new home. My Mom couldn't believe I remembered that moment because I was 17 Months old. December 1956.

[@markklausen813]

It isn't a topic of wheel size, but there's an important feature of roundhouses for steam locomotives. Most locomotives were headed into the roundhouse, not backed in. The angular arrangement of the stalls gave more room to work on the head-end of the engine, the valve gear and smokebox. These were far more important and labor-intensive than the tender.

[@carlsoll]

6:49 Such a cool shot 😳😮😄

[@silberpfeil1098]

I wonder, is it possible to do a Steam Loco Shutdown/Store Video? I always wonder how thats done, because you wouldn't leave the Locomotive while it is still at operating pressure right? And after your Video on firing up a Loco, i feel like it would be something worth doing, especially since that Video was so informative

[@Hyce777]

It's on my list of videos to film, haha!

[@silberpfeil1098]

That's wonderful! Would be really fun to see, i'm excited

[@truckinman86]

6:58 Ah. Main Street, Edmonds, WA. That area used to be a favorite of mine to railfan. However, it fell out of favor with me due to the change in parking on Sunset Ave, and further kept me away when The City of Edmonds activated the wayside horns (or as I like to call them: Horn on a Stick)

[@Two_Bears]

Great video and fun learning. I would be pretty sure the F9 did not have an alternator to drive traction motors as you stated in the video. That would be a generator as it was a DC driven unit. Of course, I never make mistakes (NOT!!)

[@evil_me]

Seems like you have mastered the new tool! 😎

[@Lowell-o7w]

Very thorough and informative. We'll done. I will make it one of my stops next time in Colorado. Eureka Springs Arkansas is a fabulous stop also

[@michaellawrence5492]

Excellent presentation piece , Thanks !!!

[@Satchmoeddie]

Hyce forgot to tell us that the passenger F3Bs. F7Bs, E3Bs, E5Bs, F9Bs, U36Bs,FPs, etc. have (had) a steam boiler with a heat exchanger for hot potable water to supply steam heat and hot water to the passenger cars being hauled by the locomotive consist. When I rode the Rio Gande Zephyr in between Denver an Grand Junction in the 1980s the train had an old F7B or an F9B passenger unit behind usually a GP7 or a GP9 MU consist to supply the steam and the hot & cold potable water for the passenger train. The air conditioning was okay but it didn't work up in the vista dome part very well at all.

[@hootinouts]

Excellent presentation. I learned a lot.

[@joestough664]

I have no idea how i found your channel, but its a unique and interesting channel. Put together nicely too.

[@johngirolamo1697]

Very, very informative for a layman like myself. Very well narrated. Thank you!

[@rickdee67]

Hyce is a great ambassador for Colorado steam. Great explanation bro.

[@mrblond750]

I’d like to take Lego for introducing me to gear ratios and developing my first understanding of power, torque and rpm. Great video!

[@F40M07]

Yes! The man is back at it again!!

[@SeaShroom950]

I go to the School of Mines in Golden with the museum being just 10ish minutes from my house, once school chills out I want to go so much and look at everything there. You've definitely got me interested in this stuff.

[@Hyce777]

Come say hi to a fellow Oredigger. Class of 2017 here.

[@SeaShroom950]

@@Hyce777 That's awesome! What was your major here? And when are you usually there?

[@Hyce777]

@@SeaShroom950 Mechanical Engineering.

[@SeaShroom950]

@@Hyce777 That's awesome, I have a few friends in MechE, I'm a Senior now in physics. I'll definitely be coming to the museum to check it out eventually 👍

[@RichardLewisCaldwell]

"Power" is the wrong word. Your hand doesn't become stronger when you grab a wrench, you've just increased the "torque". The piston stroke determines the crank length, which means that the wheels "are" the transmission: slap on bigger wheels for higher speed and less torque, or smaller wheels for lower speeds and lots of torque. Quibbles aside, interesting stuff. I learned some stuff. Thumbs up.

[@ketankhandekar4563]

Awesome sir !!!!!!!!!!!!! Very very interesting.Thank you very very much for uploading this beautiful video on KZbin sir.Extremely grateful to you.God bless you all.Have a great life.Take care and stay safe.

[@josephinebennington7247]

Good vid. Educative. You asked for comments….mine is, once you moved onto diesels, you never used the word torque, which is the important factor. You did explain why the crank position changed the torque (leverage) on steam locos, but not on diesel-electric set-ups. Over to you…

[@ridealongwithrandy]

Awesome video, I remember about 10 years ago when a huge steamer came thru the canyon not far from my house. I think it came down from Colorado at the time for a centennial of some sort. Pardon my old age remembering ... the wheels were taller than me and I'm 5'6". Cheers!

[@erbman89b]

Thanx for another wonderful engineering video. The most extreme wheels I have seen are the Southern Pacific #3025 4-4-2 Atlantic at the Travel Town museum in Los Angeles. The drivers are 81" in diameter. This video brings to mind a question I have had for many years that may be a good future topic for you. Historically how long have trains been through the years? All of the trains I have seen in the last 50 or more years are 100 or more cars long (My brother and I used to count cars as the train went by). Of course, these all had multiple diesel engines. Huge trains with only one crew to pay. How long were the steam trains? On Petticoat Junction an American locomotive pulled one car, but I suspect it could pull some more. How long were trains in the days of the first transcontinental railroad? How much did the Big Boy pull? I suspect what we see it pulling today is well under its capability. What determines the limit for a single steam engine. Sometimes the Durango and Silverton or Cumbres and Toltec double-head, sometimes they're single locomotives. How do they determine what to use? For that matter, how do you determine how much locomotive is needed at the Colorado Railroad Museum?

[@andywomack3414]

I used to work at a rail yard, early 1970's and many coworkers worked with steam. A single steam locomotive leaving that yard was limited to about 3,000 tons. That would be 30 loaded coal cars of that era, and about 100 empties. My guess for a normal mixed freight, 50 cars or so max. Double heading and pushers were a common practice. I have a memory of being on a B&O passenger train with a steam pusher that helped the train maintain speed climbing the Allegheny Front west of Cumberland, Md.

[@Hyce777]

Andy answered your question for what was mostly typical back in the day. Bigger engines could haul more, and certainly did; but the trains were typically shorter than these days.

[@andywomack3414]

@@Hyce777 But the Big Boy, and your Q monster... Nothing like that on the B&O, Baltimore Division.

[@nicom4996]

One of the best videos so far. Keep going on the professional way

[@brombrom1522]

I think you make a great presenter, Hyce. Keep up the good work!

[@davidburzo1933]

Oh wow! This makes everything sensical. Now i understand why trucks in the 80's and 90's had such small wheels. I've always wondered why something like an F150 had 15" wheels during that era. Now I i get it.

[@baldypalmsrailroad]

Great explanation of the wheel sizes. Thanks!

[@philipmcrowsr7528]

Interesting video, all your videos so far that I've seen are interesting.

[@F4wk3s]

Carl did good

[@WilliamB78]

Superb video. Very informative.

[@blubaughmr]

7:08 looked very familiar. Edmonds Ferry terminal.

[@brianhepke7182]

Very insightful video... loved seeing the different types of locos...I'm a big fan of North American trains.😊

[@carlsoll]

You see John Oliver’s ‘Last Week Tonight’ Episode on ‘Freight Trains’. Pretty good, just aired December :)

[@chazdc154]

Very informative. Thanks!

[@expediter99]

sir, I just found this video. I commend you on your spoken presentation. So often, the listener's attention is broken with 'fillers'; eg: right? OK? the old 'uhhh'. I could listen to you all day. thank you. the background music is subtle, appropriate.

[@noelcastle3986]

Great vid thanks , I always wondered how steam engines run for all loading and speed requirements with in reality only one final drive ratio. Basically the piston stroke length is based on the distance from the axle centre to the drive rod attachment position on the wheel. Sort of explains the difficulty moving a big stationary load on wet tracks although steam is much more forgiving than petrol or diesel engines as it's expansion force is linear throughout the entire power stroke and easier controlled by steam valve positioning . Sorry to waffle on ,the physics of locomotives is very interesting. More of this kind of videos please.

[@calrob300]

IDK before about witness grooves. Very cool. Car, truck and bus tires probably got the idea for wear bars from witness grooves.

[@Quince828]

A very clear explanation of why sizes mattered and why different locomotives were used for different applications. But I wonder what happened if a diesel geared for passenger service was paired up on a freight train with a freight diesel. Did that ever happen due to motive power availability, and did the passenger locomotive provide less pulling power than the freight locomotive they would have preferred to use?

[@thisnthat3530]

The reason that big wheels are used for high speed steam locomotives is because of wheel hammer. The pistons reciprocate backwards and forwards creating vibration. This would cause the train to noticably surge so it is countered by the wheel weights. Since the weights are sized to offset the pistons and conrod as well as the drive shaft, they are too heavy for vertical balance since only the drive shaft contributes to vertical imbalance. The lack of vertical balance gets worse with RPM eventually leading to the wheel jumping clear of the track each revolution (hence the name wheel hammer) limiting the maximum speed of the engine. Bigger wheels = later onset of wheel hammer = faster top speed. A diesel locomotive has the pistons and conrods with associated imbalance inside the diesel engine. The electrical traction motor is balanced, as are the wheels so it doesn't matter how fast they revolve, allowing standard sized wheels can be used regardless of speed.

[@BurnedBaconGaming]

Was the deisel wheel idea ever brought to steam locomotives besides turbine locomotives? Curious if there was some transition era experimentation with that.

[@Hyce777]

Not that I'm aware of.

[@BurnedBaconGaming]

​@Hyce777 Turns out there were a number of Steam Motor locomotives used something very similar. Though not revolutionary they did work for their intended role.

[@fiendishrabbit8259]

Although the important part isn't "diesel", it's the electric part of diesel-electric. If Diesel hadn't been available steam-electric would have accomplished the same evolution away from a wide variety of steam locomotives with different capacities and towards a more unified fleet of locomotives capable of performing a wide variety of duties (and steam-electric locomotives became a thing in some countries during WWII).