I knew that most folks on the channel would have no idea where we were on the railroad, and this was a surprising pain to make happen. Glad someone noticed :D
@@Skynd303 I was gonna say, for the true melting point of a GoPro, a firebox cam is in order... But that would be too fast to really determine any discernable temperature. For science!
Given its a round track, you could easily use a single go pro and move its position each lap at a simlar pace, then edit the footage speed just fractionally so that key markers (like the rail crossings) of each line up. Also since the shovel cam already thermally overloads and shuts down, the science of melting a go pro is already complete.
The rails are also tipped inward at a 1:40 pitch. This is called cant and is induced by a difference in the thickness in the tie plate supporting the rail. Thinner on the gauge side and thicker on the field side. Additionally, the tops of the rails are not flat but are actually curved at a radius of 8 or 10 inches. This is to keep the tread of the wheel riding more to the center of the rail rather than bearing on the edge.
Yes and no. Rails are tipped inward slightly and have a domed head to them. Not squared off in the diagram. Cant is the mathematical determination of super elevation of one rail higher than the other, in curves mostly, based on assumed track speed and weight of trains running that line. Too shallow a cant, or 'flat curve', and centrifugal force will push the outer wheelset against the rail. Too steep a cant and the cars will 'fall' against the inside rail. The proper banking of a nascar curve is also an example of this.
I thought, due to the frame, that the Number 1 and 4 drivers would be riding the outside rail, with the number 2 and 3 drivers riding the inside rail but because of the suspension that isn't the case. It's really neat to see.
Hyce, this is off-topic to the study, but you have a very good "documentary voice". Clear, heavy on the details, yet with an enthusiastic "upswing" at the end of your statements. Honestly I think you could narrate for Pentrex or another professional documentary group. You're that good.
Upward inflection "upswing" has the statement sounding like a question. That can be used as a rhetorical trick by unscrupulous speakers, who are trying to infer doubt. Some people speak like this in every sentence that comes out of their head. It becomes tedious listening. A vocal coach for a media outlet would drill that out of any prospective narrator.
@@BTW... Hmm, I used the wrong term then - I meant downswing. There's still an upswing, which is then followed by a downswing at the end of the statment.
That is my thought as well, you might get more data by mounting cameras to look at the other wheels if you can, or for one spot, put cameras on the track to look up at the wheels as the train passes over.
This is me guessing why the inside flange is rubbing, not the outside one. 1 of the ideas I hade was that the trucks were pulling on the drivers because curve, straight line and stiff medal. The 2nd idea, after watching and thinking for a little, I realized it could be because the rest of the train is pulling on it. This is kinda like when you pull a string, it wants to be straight, but the tracks are like a finger pushing in the middle of the string, making it curvy. I will see if any of those are right. Yep, 1 was right, based on your explanation. Anyway, great vid, thanks for showing and teaching us that.
Exactly my thought. It’s always seemed to me the tightening string effect would be the strongest lateral force on the wheels, forcing the inside wheel to role faster than it should, and the outside wheel slower. It seems to me that inside and opposing outside wheels should have independent axels (eg one spinning inside the other).
This brings to mind the 31 years I spent working on the Long Island Rail Road, which is the biggest commuter line in the United States. I'm sharing this video with my friend in Florida, who retired with me in 1997. Thanks for the memories!
The flange issue is also present on the Norwegian standard gauge. As I looked into the fuse panel of one of our DMUs from the 80s that is about to be phased out of operation this year, there were fuses and indicators for a "flange lubrication" system to fight the wear thing you see here. This is also why the rails here are a bit oily on the inside which you can see at the passenger stations where there are track crossings between platforms.
That’s interesting. My great-grandfather on my grandpa’s side of the family used to work at the juniata shops in Altoona and probably knew a thing or two about this. Maybe not though, as he mostly did wood working on the coaches and whatnot.
Great video! Another fabulous demonstration of the difference between theory and practice. After 50 years of practice as a hardware and then software engineer, I still love videos like this that starkly show that the real world is usually different from the imaginary world we write about in our notebooks and on our whiteboards. One nit about the opening segment regarding wheel geometry. Although you show it in your drawing, you didn't mention the filet that transitions the tire into the flange. In addition, the inside edge of the railhead has a similar complementary curve. The dynamics of how the wheel behaves as the filet engages with the curved portion of the rail head are fascinating and not at all obvious -- at least with regular trucks as opposed drivers on a locomotive. The short form is that for the flange to get close to the railhead, the rapidly increasing radius caused by the curve of the filet has the effect of LIFTING whatever weight is bearing on the wheel. The curve of the railhead contributes to that effect. The interacting compound curves of the filet and railhead translate much or most of the vertical gravitational force into lateral force acting to center the wheelset. As a result, gravity forces the wheelset away from the filet and keeps the wheelset on the track. My understanding is that standard-gauge track (not narrow-gauge and not streetcar/traction track) is intentionally designed so that the flange almost never makes contact with the railhead. If it did, both the flange and railhead would be very quickly ground away to nothing. Oh -- and one last historical note -- all these impressive dynamics were investigated, worked out, designed, and patented in the 19th century. The interaction between a railroad wheel and track is a masterpiece of mechanical and civil engineering (not to mention draftsmanship in the original drawings!).
Great and informative video. Maybe next time train the cameras on the tender or coach trucks and see if they follow the "rules" since they have a much shorter wheelbase than the drivers.
I think you’re overthinking the whole thing here. It has nothing to do with tapered edges or flanges. It was clearly the Flange Trolls that live in the journal boxes that were pushing on the axles. The are fed when someone is oiling around and Smurfs all over the place- the blue color is what draws them in. Our steam engine here at Monticello has them too!
What I believe to be the case, judging by the uneven flange wear on the inner No.4 wheel, is that the wheels may have lost their profile over the years, and need to be re-machined to their proper profiles. Granted, the tracks being of too tight a radius for 491 won't help either. I can't tell if this is a case of the video perspective and the ultrawide GoPro lenses, but the track may be uneven across its width, which could potentially cause the train to prefer running on the inner rail as if it were a coin rolling down a funnel. Either way, nothing that some standard maintenance shouldn't fix - and by no means do I wish to imply that you are neglecting your fleet. Keep up the good work alongside your comrades, Hyce!
I would say your assumption on the wheels is likely accurate. This is what I was thinking before you went into your explanation but I did not know the configuration of the loco and was assuming 0-4-0/2 and thinking that 4 drivers in a group with the front driving on the opposite side (as the front truck does) and thus pushing the rear drivers to the other side. I was making assumptions on the information I didn't have. First video of yours I've seen, but yeah, good explanation and accurate. I appreciate the suspension breakdown of the loco so I can understand what's happening and the visualization helps. Props to you!
Hyce: Why can't you just act like a normal flange! #1: *Screams in Agony* THIS IS WRONG #2 and #3: *thumbs up* Understood #4: *Confused Screaming* WHAT IS HAPPENING!? Leading and Trailing Trucks *evil grin*
Two item not mentioned. Most track uses canted tie plates that aid in centering the wheel set. Curves are built with some superelevation to balance some radial force with the weight, like a banked race track. Your initial theory works for a single axle wheel set but need adjustment for multi-axle trucks, as your followup discusses. Think about reversing the operating direction, maybe seasonally. This reversing will also have some impact on the tractive forces driving the track downhill.
We do operations in different directions to alternate wear already; can be hard to keep it even though. Superelevation does play a part, that would've been a good add.
I work on a standard gauge railroad in the US. We mostly do industrial switching and fairly short runs between yards and areas that we switch. In theory you don't need the flange, but I can tell you in practice those things ride on the rail all the time. Particularly through switches and tight industrial tracks, you hear them scraping the whole way. Also, it is important to remember that not all railroad track is as perfect as a Class 1 mainline. The majority of yard and industrial track is old and made out of sections that are often shorter than modern railcars. There are definitely areas where the gauge sags inward or outward. If this happens enough you'll have a derailment, but in small amounts the flanges can help keep the wheels on the rails.
This has been the best railroad show I have ever seen. I wonder when a train rounds the bend whether the wheels of a freight train squeal like the wheels of a rapid transit or subway train. Are the wheels of a diesel locomotive the same in size and weight like those of freight cars? This show is the main reason I used to ride between the cars on a New York City subway train. Those times were when I was younger as long as forty years ago. Thank you for this special railroad education. Happy Railroading!
Cheers mate! Diesel locos have similar size wheels to many cars; though in this case, we have a steam engine with 44" drivers vs. 26" wheels on cars. Very different.
Thank you, Hyce for your spontaneous reply to my question. I am pleased to be mate. I only had closeup views of the freight trains I have been interested in, since I was a little child. Now, I am learning much more about railroads on RU-vid, as a subway buff and a railfan. I do understand that the wheels of steam locomotives are smaller and bigger than those wheels of passenger and freight cars. I have looked at platforms like Wide World Of Trains, JawTooth, and Mark McGowan, I acquire knowledge without being present at the rail sites. Once again, I thank you for tapping or typing to me, depending on which apparatus you use. Happy Railroading!
@@Hyce777 Thank you, but you do not have "stuff." You have material that comes to life. Thank you for tapping or typing to me. Once again, Happy Railroading!
I can't say I have a better idea than that it's because of the way everything is connected in the suspension, but I think a very interesting experiment to do would be to get an axle with wheels from something that had blind drivers on that axle, and put it on the tracks and either by hand, or, if it proves to unwieldy this way, with the aid of a Goose or similar small motive power, walk it around the track and see where, if anywhere, it is inclined to pop off.
Some British locos did indeed have blind drivers; they were 2-10-0 configuration, and the middle wheels (i.e. axle no. 3) were blind. Although there were never any problems, the railways weren't entirely happy with this, and preserved examples of these locos are now banned from the mainlines.
Before seeing Hyce explanation and thoughts: the lead and trailing wheels are doing exactly as you described in the diagrams. That's going to be pushing the middle of the rigid frame over the inside of the curve, easily seen with long cars. Locomotive has drive wheels all through the middle that are pushed against the inside edge because of that. I would think that's also the biggest limiting factor on how sharp of a curve a locomotive could take. Edit: after seeing Hyce's thoughts, I thought the same as him but wasn't sure if the suspension affected the lateral travel of the joined drivers or not. Still same thought though, just through the suspension pieces instead of the entire locomotive. Probably same thing happens on a 6-axle diesel then, middle set of the bogie rubbing inside rail.
To test your hypothesis, just move the GoPro's to the other wheels. Other than that, can you attest to the condition of the wheels? Do they exhibit strange wear patterns across the width of the tire? Such as a low spot someplace across the width? The lighting wasn't great, but it seemed like the tire was cupped near the middle of the tire where it rides on the rail. If the cone shape is distorted from wear and tear, it will certainly affect the normal cornering action.
I can't theorically explain the phenomenon but by experience, I can say that the small taper on the wheel have the mission of center it on the track and avoid the ribs rubbing on the side of the track so the friction is limited. What I can say is that when a curve have a small radius, the squeal is infernal and the only way to limit it is to paint a coat of graphite on the track
Reminds me of flat belts/sanding belts on crowned pulleys, which also don't move the way one might expect (they self-center on the largest diameter)... not sure that comparison actually holds any water, the suspension explanation makes more sense to me (especially if the curves are close to the minimum radius for this locomotive)
Equally interesting is the Crown Wheel.Found on traction engines where the same effect is caused by having the centre of the pulley of a slightly larger diameter. No flanges but a flat drive belt will self centre . System is used to drive tape decks and similar devices. The principal is the same as the train wheels.
Interesting but would be much clearer if the views were straight on instead of at an angle (or at least a smaller angle). Separately, thank you and everyone at the museum - the museum is a state treasure, if not a national treasure! Even just the collection of Galloping"Gooses" is amazing!
i've seen this on older 4 axle diesels. every axle has the inside flange scraping when taking a long curve. put some go pros on ever wheel plus the tender wheels and all the wheels of the first car.
Now look at ladders. How can a 180 pound roofer carry a bundle of shingles to the roof using a a ladder than one man can carry? May not be “high tech” but it’s high something or other.
Are the curves super-elevated/cantered? Maybe the loco doesn't go fast enough and "falls" to the inside? Loved this video and your explanation makes sense to me and is probably correct. Prof. Hyce, now we need you to get more GoPros and film the other wheels at the same time too please!
No Cant on that track that I ever noticed. Pretty flat to the ground. About as flat as the The Nevada State Railroad Museum in Carson City is, only their loop is more of a perfect Circle(not counting the Wye they have at the North end) than an Oval. They run the Glenbrook(2-6-0) there and I think they have the same issue. I'm drawing the same conclusion, it's because of the frame design and suspension.
I forget which type in particular, but I remember reading that one of the 3 main types of geared locos here in the U.S. was briefly offered with actual differentials in the trucks, but they didn't last long as an option because of limited orders and the fact that they (apparently) greatly reduced tractive effort in turns.
That's a new one on me... never heard of that! I have no idea how they would have supported that in terms of bearings to keep it from falling apart. Had to be a Heisler or Climax, because the Shay or Willamette was driven from the outside, not center.
Wow, awesome footage! I can't think of another reason why the wheels are riding opposite of expected (unless one was way out of wear and throwing things off). Without the lead/rear trucks Drivers 1/4 and 2/3 would probably behave opposite of what we see, as Midland1072 Productions observed already.
With narrow gauge locomotives find what I have found out is locomotives with outside connecting rod have less lateral motion. Standard Guage steam locomotives have a limited amount of lateral motion. But one thing to consider is the degree of curvature. It’s possible that the degree of curvature it possibly to tight. That would be a factor. Also I did notice that the drivers are starting to show signs of cupping on the tread surface. Look up to see what the manufacturer recommended degree of curvature if it can be located. Best of luck
The manufacturer calls for 30 degrees max; we have 28. We do have a small amount of tread worn hollow, as you described; but it's nowhere near the limit. We also don't have any wheel conditions that require truing yet.
@@Hyce777 what is the condition of the railhead? I couldn’t tell if the crown of the rail is still intact. Also with curvature the industry practice is to have super elevation in curves. This helps with helping a rigid frame locomotive thru curves. The smallest to the largest locomotives have the same issue with flat and non super elevated curves. Articulated locomotives also requires super elevation. There are many other items that could be contributing to your situation. Spring rigging will hamper rigid frames in curves if it’s not properly maintained.
Fascinating, but logical. It is a tight track. 7 1/4” model railway says 3 degrees and 45mm gross bahn is happy at 5 degrees with massive flanges. I’m building a 7 1/4 so I have been looking at dimensions :o)
When a tapered wheel is rolling down a straight rail, you can imagine a longer circumference next to the flange, and a shorter circumference on the small end of the wheel. So if the wheel somehow made full width contact with the rail, it would have to skid on either side of the contact point. The wheel would wear the rail on either side of the contact point, or the rail would wear the wheel, depending on your frame of reference. So when the wheel rolls around a curve, the outer wheel needs to roll farther, and the inner wheel needs to roll shorter. So the outer wheel creates a steering force that moves the contact point on the inner wheel towards its larger circumference near the flange (trying to speed up the inner wheel). The inner wheel steers the outer wheel to the outside where the circumference is smaller to try to slow down the outer wheel. Neither wheel can 'win' this argument, so they find an equilibrium point where the least skidding is created.
My 2c: All objects want to continue in a straight line unless another force is applied to them. Consider a car traveling down the road and into a right-hand corner with barriers on the outside. The car doesn't turn but goes straight into the barrier, hitting the front left corner of the car against the barrier. The potential energy in the car wants it to continue straight but a force (barrier) is applied to the front left corner to stop it. The rear right hand corner also wants to continue straight, being not directly inline with the contact axis of the left hand front corner it has a leverage or torque about the impact point, push the rear right of the car out to the right. Most likely spinning the car. 491s leading driver axle is the same, the loco wants to go straight (disregard the front truck as it's a super sharp curve and beyond it's ability to pull the frame around) , the front axle wheel hits the outside rail and the fixed wheelbase has a yaw or turning moment about the point of contact with the opposing force (the outside rail). This pushes the rear axle in any fixed wheelbase against the inside rail. So basically the loco doesn't roll around a curve, it is wedged around the corner, eg lots of wear, eg manufacturers of locos and track go to great lengths to ease this wear through elaborate leading/trailing truck centring devices, track and rail standards, minimum radius curves etc etc.
@@Hyce777 sorry. I meant beyond the ability of the lead truck to pull the front driving axle off the outside rail. Which I would think only happens in 'slight' curving situations.
Your summary was my first thought. I don't think you mentioned that the leading/pilot wheels are laterally sprung to help keep them centered and this spring tension is what leads the locomotive frame into curves. Interesting fact, the tapered wheel treads cause sinusoidal (hunting) oscillation in two axle trucks. This was an issue with the design of modern high speed trains. Reduced tread taper, coil suspension and high precision track was the answer.
Interesting about the tapers causing hunting; hadn't heard that. Our lead wheels are not just sprung, there's a spring + some geometry, which I didn't get into, as I have a whole different video planned to follow on with that.
@@Hyce777 The hunting happens on trucks with the bolster between the two axles. I'm not sure about that aspect on leading wheels considering the pivot geometry. A video you may want to watch: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-SRsm7mv0Oh8.html&ab_channel=mechanicalTV27
I think your theory is right. If you think about it, you have a rigid frame going around a bend. So take that rigid frame and put wheels (or maybe pegs) in the front, middle, and back of that frame. The front and rear will rub against the outside because of centripetal force. But if the frame is longer than the radius of the curve (I think it's radius), then the middle will rub on the inside as it's turning acting as a pivot point.
Your at a slow speed. At higher speed centrifugal motion becomes more apparent. As a Brakeman on the GN in the sixties on a road trip West of Cloquet, MN there was a curve restriction of 35 MPH. Just short of the curve the Engineer went back to check the units. When entering the curve, the head unit went through transition (traction motors going from series parallel to parallel) which happens at 48 to 50 MPH. The engine speedometer was showing thirty-three. In the cab there were a series of loud bangs. What was happening was the flanges were climbing the rail and falling back down. The curve was to the left and to the right was the St. Louis River, a sharp bank, down twenty feet, and a river strewn with large protruding rocks with rushing water. At the end of the curve the Engineer burst back in the cab and asked if the Caboose made it!! That was one of the closest brushes with death I had railroading. Over thirty year there were more to come.
I think the reason being for the inner flange to rub on the rail is firstly the lack of sufficient velocity for given sweep and secondly the actual rail is probably slightly super elevated on the outer radius rail. In order to have the axle shifting how it supposed to the rail would have to be dead level horizontally I assume
Cars tend to tilt towards the outside on their suspension, based on weight, leaning their mass onto the outside tires, giving more grip. Maybe this also happens here, but it is so much, that the wheels shift towards the smallest point of their diameter as much as possible, simply based on the additional weight pushing onto the axle, which might be way more force than slip of the wheels. Just guessing.
I am not that familiar with the Mikado type so I don't know how it's suspension and any articulation it has is setup. But a problem with ridged frame is how the center gets pulled over the inside of the corner just like how a semi trailer does at a tight bend. Some railroads did use flangless drivers to get around this problem such as PRR but it wasn't a full fix. The only real solution is better articulation.
Tbh its easy consist the wheels flanges press against the rails, thus preventing derailment there is times where if you go fast or have too many wheels it cant bend and it will derail so the wheels move a train the flanges keep them on and the rails guide them so really the only {some cases :) } solution which big boy and challenger used was a you got it articulated wheel base so yea thus solution but anyway. but im really stating the obvious here so yea cause its 4 am im tired and its easier to dumb it down when your tired. have a Great day/night/morning/afternoon/evening/midnight, and Hyce, Keep up the great!! work :)
Think of the train going around a curve. If we're looking at the train from behind, and it makes a left turn, the train would pivot on the center of gravity. So, the top of the train would pivot away from the turn (i.e. to the right), and the bottom will then pivot in the opposite direction. Hence, the wider gap where you don't expect it. Your thought that the gap should close on the right side (the outside) would work if the train stayed completely upright through the turn, but of course it won't.
Easy solution. Add flange greasers to your railroad. Also you need to wye or balloon you’re a locomotive and run it the other direction on your circular track.
What I would like to know is are the #2 and #3 axles blind drivers. That would explain this. The rear most axle will off-track to the inside, it's the rail that actually stops it from doing it more. Think about how a trailer, or even the rear axle of your car off-tracks when you take a corner. Same story here. Unless your curve is sharp enough, and speed high enough to force all the axles to the outer rail, this will happen. Great video though.
The cars center of gravity is very high. As the curve is rounded, centrifugal force pulls the top of the car outward. As weight is transfered to the outer wheel it sinks lower and shifts inward due to cone shape. The inner wheel is forced up its rail until contact is made with the flange, keeping the car from rolling over.
Simple answer: The theory of the angled wheel shape and how they ride has to do with the rail cars, the stock cars on a normal 4 wheel truck at each end in normal situations with a coupled solid axle, not the engine wheels. Since your engine is the driving force of this depending on the load it will always gravitate to the inside rail since it is the inside of the curve. It is possible as the train flows down the line on a curve that each car will set differently with the last cars riding as the rail car theory goes, but the one closer to the engine might be closer to the inside rail as well. It is like taking a rope around a poll, is the rope going to rid against the poll or slid out to the edge, no it will ride around the poll not a few inches away. Now if the poll was a few miles wide and the rope was traveling at a good rate of speed yes it will now tend to ride away from the poll. Thanks for the video; this also explains why most model train engines have flat edges on the drivers and the rail cars are tapered.
Interesting thought; overall I believe the locomotive does "ride around the pole" as you described, but I don't think some wheelsets will make it based on the geometry. Going to film each one and see what happens...
@@Hyce777 So to save on wear or balance it out run the engine the other way around the track to get the wear balanced. Also I learned recently that on the main line tracks they have oiliers for those hard and long turn spots to save the wear on the tracks and wheels.
Dont know the full specs so just a guess, but in theory the taper of the wheel should be proportional to the radius of the rail curve for the full theory to work. And by the looks of it you are running a really tight radius museum track. I would also take a guess that the loco has probably been running the same loop of track in the same direction for years. So based on the current wheel taper the wheelset is trying to self center but running out of room so hitting the flange. Not a train guy just a maths guy.
Very good information and insight. Those are some sharp curves at the museum and those pony and trailing trucks are quite a distance from the drivers which would account for the 1/2" or so they are offset on the curves. '91 is probably pretty "stiff necked." I don't think they designed much lateral play into her drivers.
As it was explained to me, the pulling force acting on cars in a curve can be visualized like a floating compass needle at the front of each car. The needle always points to the engine. In a right turn, the needle deviates slightly right, pulling inside wheels against the rail, and leading to possible straightlining if the car is too light.
Those tires are not sloped enough to force the them to ride up. The reason the inner wheel lip gets closer to the rail is because it is being pulled inward by the train car itself, which in a right hand curve is always to the right of the wheel.
You sound like someone that should subscribe to the trade publication: “Interface - The Journal of Wheel/Rail Interaction” where all the science of steel wheels on steel rails gets discussed. The suspension theory makes a lot of sense. Would be interesting to try a few things to validate that theory such as… …running the locomotive for a lap in reverse - although the buff forces from the tender may add a lateral load into the frame that causes the rear driver to overcome the inward forces of the suspension, possibly causing the #4 driver to pull away from the inside rail. …repeating the tests with a locomotive that lacks a trailing truck (346) It would also follow that the repeated laps around the loop with the forward-most and rearmost driver always being forced to slip/scrub you would in time see a different wear pattern on those tire’s treads; I would wager the taper disappears more quickly on those drivers.
I need to look into that publication! I have not heard of it. I filmed every wheelset on the 491 yesterday to make more comparisons in another video. I want to try 346 as well, for the no trailing truck and also blind drivers; but she's down for overhaul so it will be a few years.
This effect is decribed in an 1833 article on the Camden & Amboy (think John Bull) where the writer notes that the flanges of the wheels on the center axle did not rub the rails no matter how fast the locomotive was driven.
Because a locomotive trucks/ bogey can swivel, and steam engine doesn't ( because of the push rods) would that same system apply. Your video was very interesting.
while breaking in slot cars the tires would cut the inside track until centrifugal force causes slippage and if balanced correctly allows a drift condition.
First thought- (probably the only one) is that you are running tighter than "normal" bends on your track, and that the train is being dragged into the center od the turn, coupled with lower than "normal" speed on the bend. If I'm right, you will either have to go faster (not recomended) or set the track with the outside rail LOWER than the inside!
Because the outer wheel is higher up on the track it pushes the train towards the inner rail because the shape of the wheels always wants to be centred. I guess it could be fixed whit another angle on the wheels, a different radius on the track or a slower speed.
You didn't talk about the rest of the train. Could it be that the weight of the train is pulling everything towards the inside of the curve as it goes around?
At first I'm thinking if the wheel is worn down so much it's doing that but does seem right how you explain it would be nice to see what it does when just going through a switch and looking at the different drivers
Basic Physics. It's momentum. Try it in your car, sometime. Go around a curve, and you (as well as anything else in the car) will shift towards the outside of the curve. Momentum makes objects "want" to continue moving in the same direction, even when there is a change in velocity (the direction component of velocity). Momentum is equal to mass times velocity. (Velocity, not speed, as velocity is a vector (includes a direction component), meaning that velocity is equal to distance over time in a chosen direction.) The locomotive, and the entire train, are quite massive. The amount of momentum is thus great, even at lower velocities.The train "wants"to continue going straight, even as the track curves, causing the entire train to shift to the outside. (Because of the engineering of the truck sets, however, the opposite wheeled axle will most likely have the flange of the outside rail pressing against the rail. Otherwise, the structure would fail, due to incredible amounts of torsion.) Momentum is indeed also responsible for trains, or any vehicle really, rolling over, if going to fast around a curve. It's also why race tracks are slanted upwards, from the inside to the outside. Momentum will always pull an object towards the outside of a curve.
Does 491 have lateral motion devices? I've never "*exactly*" known how those work, but have always assumed that the way you show is what they're for (letting the axles better form a radius to meet the track curves). You've mentioned before that the museum track has often been tight for 491, (moving the radius, lifting the track up etc) and it makes one wonder if those curves are on the edge of too tight. The simplest solution theoretically, is just balance clockwise running (or rubbing) with counterclockwise running, and expect the cost of sending the drivers out to Durango (or Strasburg, TVRM, or wherever etc.) for re profiling or replacement more often than on straight track. Might be worth getting cameras on the other drivers to confirm your theory.
We do run both ways, and in the 8 years she's run she's not really worn the flanges too bad; but it is a worry. She does have a lateral centering device on the #1. There's video of it in the loco 360 video. She is spec'd out for 30 degree curves, we have a 28 max. The stories of her doing crap was prior to the rework and fixing ballast.
Worn Wheels with a slight false flange. They have lost their positive conicity value and look like they are running negative conicity now, wheel should be about a 1 in 20 angle for a basic profile after machining, if hollow wear occurs, even though it is well within allowable tolerances, the opposite effect can occur at low speed curves. Lots of other issues to add in like "cant" value etc. If hollow wear is allowed to get to bad you may experience hunting at high speed on straight track as well as flanging which is something that you want to avoid as this increases flange face wear. my thoughts anyway
Great vid. It sounds logical to me. I will have a look at that next time I send a long loco around a number 1 curve sometime and see if it does that same thing? Regards, Jas. VK4FJGS Rocky Qld
Yep, good summation. Makes total sense. So have ya checked flange wear to compare on the loco? I’m guessing you’ll see exactly the same wear pattern. Good discovery and video.
Baldwin workshop manual explains that when a steam locomotive enters a curve it is assumed the leading driving axle wheel will up against the outside Rail and the rear driving axle wheel up against the inside rail. This is known as the angle of attack or yaw. This is also the same for a passenger trucks etc. The idea of the front and rear engine trucks is to assist the locomotive to negotiate curves. The front engine truck through various devices such as swing links and cams etc. pull on the engine frame reducing the lateral forces being applied to leading driving wheels due to the effect of the curve. Hence reducing wear and tear of the leading driving axles on a 2-8-2 loco. Typically the front engine truck would not normally apply sufficient curving effort to the loco frame to move the leading driving wheel off the the outside rail. However, the curves the K37 is negotiating are very sharp. Depending on the design of the front engine truck and the radius of the curve the curving effort being applied by the engine truck to the locomotive frame is limited (percentage of) by the weight on the front engine truck axle. Too sharp of curve and you will derail the front truck. Therefore, I am not sure the leading driving wheel flange would be off the outside rail.
Is there any super-elevation of the track? Is the outside rail higher than the inside rail, or is it level across both rails? In roads for cars and trucks the outside of the curve is generally slightly elevated and the amount of the elevation is dependent on the designed speed limit, (higher designed traffic speeds have greater super) and the grade, while still maintaining a certain amount of crown for drainage. As a traffic accident investigator I determined “minimum speeds” based on skid marks and other pavement mark evidence. Pavement grade, curve radius, super elevation, pavement coefficient of friction, along with the curve radius of the skid marks were all variable plugged into a standard formula.
Technically the rail head is also profiled to control the contact area, but based on how consistently this rides on the inside I don't think this is a track issue. If your theory pans out that it's related to the wheel configuration, what do you think this means for blind drivers? I've read about 2-8-0s and I think 2-8-2s that used blind drivers on the #2 and #3, which seems a little weird given what we're seeing here ... Very interested for a part #2 of this!
Inertia is pushing the train forward and it still wants to go forward it's only the inside flange that is .... keeping the Train on the track at this point, it's physics.
I would mount a camera on the first cars wheel sets. The middle cars wheel sets and your rear end cars wheel sets to get various points of data. I think the shear weight of the locomotive is haveing it lean/toward the center of the curve. Put a bubble level and camera on the front of the locomotive facing away from the train so we can see the train round the curve and see with the level which way the train leans. Or the curves are just to tight. My model trains rub the inner rail if the track radius is too tight. It happens with my longer locomotive. I think the locomotive has too many wheels for to tight a curve. Im talking out my bum but those are my ideas.it would be most awesome to have a drone capture a Ariel shot of a train going around like how you had in the video.
Is the area where the wheel contacts the rail as narrow is in your sketch (like a point), or wider due to wear? I'm working on modifying a wheelset from trundle gauge to standard, and wheel/rail contact area my be an issue for stresses.
When I was a teenager in 1960, we would drive a '51 Ford onto the railroad tracks and ride between crossings on the rails. We did not have to steer the car to keep it on the rails. Has anyone else done this?
Is it a question of camera angle, but it looks like the diameter of the wheel right adjacent to the flange is smaller than the diameter of the wheel furthest away from the flange.
Here's a question, might sounds totally out there but keep in mind that i'm a car guy and not really a train guy. Seems like the construction of the locomotive doesn't allow all the axles to wear evenly because you're doing laps only one way so how about fixing this by switching over the axles after some time to get the most life out of them. Where there's the group of 4 axles just swap them around 1 with 2, 3 with 4 after an X amount of time. Same can be done with the front and rear single axles. If you cannot alter the route then at least switch the axles around so they ride differently and act as if the loco is running opposite way laps. Would that be possible?
We do turn the engine around. Unfortunately, with the way the locomotive is constructed, just swapping axles isn't really possible; you couldn't even spin one axle around left for right as the rods are set up to be offset only one particular way. Imagine you're trying to flip around a crankshaft, rather than an axle.
How much up and down movement of a sleeper while train running on track is allowed? Sorry for bad wording. For instance I watched a train go by my house and the sleeper would sink about 1inch into the ballast and spring back the spikes were obviously have pulled out overtime
It depends on the class of track; sometimes *quite a lot* is allowed. Sometimes, hardly any. An inch doesn't sound too bad, particularly if it's medium speed or less freight.
@@Hyce777 standard freight, mostly excess height car haulers, and open hoppers for hauling steel rolls. No passenger traffic. But I only noticed because I noticed the spikes are no longer fully seated on the "bouncing" sleepers.
What is the squealing sound that you hear from train wheels. I first thought it was braking but now l think it must be the flanges. It is squealing scraping sound?
I would take a look at all of the flanges at the same time. I would be willing to bet that the others are on the opposite side while going around. If it was a single axle, or even a 2 axle setup, the angle would have more effect and the twist would have less.
@@Hyce777 That would be very cool. As a truck driver, I see a simmilar thing happen with the tires of the drive axles as the truck turns. The front axle tires, flex away from the turn and the rear axle tires flex toward the turn. If there are more than 2 axles, they all flex depending on the weight distribution and which one is the center of friction.
