Flanges, To big OR Is Wheel to Small!

[spankybird]

Us City folks can't get, don't have RFD-TV

darn, darn darn no trains on tv.

tom

[NH_Chris]

RFD-TV recently showed a video on the closing of the Stockton, CA switchtower, which controlled switches at the junction and crossover of four different tracks, with four separate diamonds.

Much of the video showed modern equipment rolling slowly over the diamonds. From what I could see, the wheels of each car dropped and klunked twice each time they crossed a diamond.

Also, the cars swayed quite a bit as they approached the diamonds, because the trackwork was not nearly level. Of course, prototypical track has vertical rises and falloffs in a single track section, which is much less likely to occur in 1/48 scale.

I wish I had known of this issue before I watched the video, because it may have answered some of the questions above...

NH Chris

[jkerklo]

Verify by observation, how wheels go over the gap.

Do they just bounce over, or does the outside of the flange ride on a built up area.

I think it has to be the latter, but remarks in this discussion say no. Maybe, there is more going on that we know.

I do know some shallow angle diamonds have moving rails, like a turnout, but are not a turnout. While waiting for a train crossing one of these as a child, I asked my father a question about it. After the train went by, we went over the tracks and he parked the car and took me back to the tracks and showed me how it worked. There was even one of those switch towers like a shack on top of tall square post. The switchman watched us, my father waved, and he waved back.


John Kerklo
TCA 94-38455
www.Three-Rail.com

[lionelsoni]

Ken, because of the wheel conicity, the yaw rate is proportional to the (negative of the) lateral displacement. The lateral-displacement rate is proportional to the yaw. Thus the second derivative of lateral displacement is proportional to the negative of lateral displacement. The solution of this differential equation is sinusoidal. That is, once disturbed, the truck oscillates left and right, as I have had the opportunity to observe, riding in a car with holes in the floor.

John, if you can get your hands on a tie plate, you can easily measure, or even see, the difference in thickness from one side of the bed to the other. The rail itself is symmetrical--the tie plate is what gives it the cant.

There is a diamond crossing nearby. I would be happy to examine it for you. What would you like to know about it?

[eZAK]

Given what I've read so far, even though no one has actually answered the underline Q,
a 1/48 scale wheel would be aprox. 3/4" O.D.

That would make the O.D. of flanges on our toys closer to scale than the wheel it self.

In other words the flange is NOT over sized! It is the wheel that is under sized [:D]

[Eriediamond]

Gentleman-Ladies, There seems to be some debate here for the reasons of tin-plate wheel design. Some answers and information I agree with and some I don't. One reply stated that it's a misconception that conical wheels are designed to keep the wheels centered between the rails. They are designed, infact for that exact purpose, the yawing is infact, caused by the wheels doing that and the flanges are there only to help, as he stated that they touched the rail occasinaly. If everything was perfect, no friction in the bolster, both rails in perfect alignment, both rails being the exact same height, no centrifical forces on curves and no cross wind condtions, then the wheels would keep themselves centered and no flanges would actually be needed. Now, for our tin-plate Lionel, American Flyer, Marx and others. The main reason for those high angle conical wheels with oversized flanges has been hit upon here but two of the biggest reasons seem to have been overlooked. First, thse trains were designed to be set up on the floor and played with and not operated on scale like curves or speed or perfect track. Second and the one most important reason for the wheel design is that all these trains had truck mounted couplers so these trains could negotiate the sharp curves, both forward and in reverse as well. How many times have you scale modellers answered to people with derailment problems to body mount their couplers. The tin-plate manufacturers answer to these problems was the cone wheels with deep flanges. We sometimes forget that these trains were designed to be played with by kids and made as inexpensively as possible and not for fine scale modellers. Anyway, this is just my believe, and anyone is welcome to disagree with me.

[Buckeye Riveter]

If you can keep your track gauge tolerance the same as the prototype railroads and then reduced to scale you are on your way to reducing the size of the flanges on your model trains. From some rough calculations, based upon a 1:50 ratio and a tolerance of gauge at + 1/2 inch for the prototypes, Big Boy better keep that Gargraves track tolerance (slop) to + 1/100 of an inch or be fined by the FRA. If he can meet or exceed the 1/100 tolerance, he is on his way to reducing his flange size proportionally to the real flanges.

Although the model is a scale or semi-scale representation of the real engine or car, I don't know of any model that has exact scale operating characteristics such as wheel friction, axel loading, spring coefficients, deformation, etc, etc.

http://www.ble.org/pr/archive/headline033100a.html

[jkerklo]

I run mostly postwar, and your right about the problems. It is not so much that the wheels spin on the axles, but that they wobble and shift, sometimes a lot. Cars that derail get removed, but I am going to have to address the problem someday, or keep buying rolling stock, forever.

I tried to come up with an easy way to add some sleeves to wheels, but the shear volume is overwhelming. The machinist in me is still tempted.

What about real train diamonds? The area that the Forney museum in located in is rather industrial, and there is a lot of train track around, but I couldn't find a diamond. No real need for one, I guess.

Someone is going to have to go to Rochelle and take a look. Who is closest?

I have some more pictures for you. I will post them in a couple of days. 4005 has a good home.

John Kerklo
TCA 94-38455
www.Three-Rail.com

[Big_Boy_4005]

Yup John, she shares the "roundhouse" with me these days.[;)][:X][:D]

Thanks for the cool photo. Makes me want to visit all the more.

By the way, it is true that some of our toy train's flanges do srtike parts of different track elements. While there may be some inconsistancy in wheel size and flange size the bigger problem may be the amount of slop around frogs and flangeways. If the rigid wheelsets found on modern equipment were gauged properly and uniformly, a lot of the track tolerances could be tightened.

Some of the worst offending equipment has to be post war with it's wheels that spin on the axles. I made the decision a long time ago to not run my post war trains any more, they just cause too much trouble.

[jkerklo]

Here's a shot of a steam engine driver, showing the flange. Apologies, but I didn't take a ruler to hold up. Next time.



The flange was about an inch, maybe a little more. Definately not 2 inches.

The wheel/rail surface is not square and flat. It was slanted, curved a little, and higher next to the flange, as Bob described. The rails it is sitting on are rounded on the edges, and the top is a gentle curve, not flat.

I couldn't verify the "toe-in" aspect of the rails, but since this was yard rail (in a building actually) it wouldn't necessarily have answered the question.

By-the-way, Elliot, this is a shot of a driver on your namesake.

Hey, as I signed on, I saw that Big_Girl_4005 was also on. Any relation?

John Kerklo
TCA 94-38455

[FJ and G]

Here's a neat website relating to Proto48 and tiny flanges:

http://www.proto48.org/p48_art_05.htm

[FJ and G]

John,

That's good news indeed. I had imagined them tearing out the tracks soon. There are some speeder clubs around the country who might enjoy tripping there.

Tony,

Some folks have planed homosote but that creates a dust storm. Other folks have laid the track and then tested and retested the tracks for months, making minor adjustments to the L-girder risers and to the cant of the tracks using shims.

In my experience I find O scale much more forgiving than HO.

Dave V

[Anonymous]

I believe I read somewhere that the real railroads have tolerances for the difference in height between two pieces of rail that we simply can't reproduce on a layout. The logic goes like this:

Suppose you work really hard & don't have any two sections of track that have a height difference greater than 0.1 inch. That seems pretty close, right? Well, if you scale that up to the real thing, thats a height difference that's closer to 4.8 inches. No railroad would allow two adjacent pieces of rail to be that far out of whack.

Jim Barrett emailed me his procedures for getting smooth track. He uses cork roadbed & planes them so that the transitions between pieces are smooth. Maybeyou can get the same effect with a sander, I don't know. But getting smooth track work takes effort and patience, it seems.

Tony

[Big_Boy_4005]

Yes Bob, but crossing can be confused with GRADE CROSSING, where a road crosses the track.

So to recap we have crossover, crossing and grade crossing. Before I get crossed up or cross, I think I'll stick to calling the intersection of two tracks a diamond. [%-)][swg]

Beside, have you ever tried to give the woman in your life a crossing? I think she'd perfer a diamond, don't forget to ask her if she wants O or 027, and what degree.[:P]Just watch out for flying trains, if you ever cross her.[swg]

[Anonymous]

call it what you will... i'm gonna call it the "four-way-crossover-switcheroo-thingy"!

most toy train switch frogs have a rail shoulder for the flanges to ride up on, some dont.

the prototype doesn't ever ride on the flange, unless derailed.

[lionelsoni]

You can call it a crossing, or a diamond, or a diamond crossing. See http://www.sdrm.org/faqs/defs.html

[jkerklo]

Elliot,

Not sure about wheel flanges not ever supporting the wheel.

On toy trains.
If I look carefully at a 45 degree DIAMOND, the plastic part in the center has a raised area adjacent to the outside rails. This area has clear marks, worn grooves even, from wheel flanges.

As I look at a well used O22 switch, there is a strip of metal by the gap. The metal has a clear marking of grease.

My question about wheel flange height was motivated from an observation that some cars went over switches smoothly, and some bounced.

For real trains, I haven't looked at a diamond closely, but I don't see how wheels can go over a gap without either using the flange or dropping down a bit. Dropping down has to be a more serious problem, since the wheel would then have to be pulled up again.

John Kerklo
TCA 94-38455
www.Three-Rail.com

[Big_Boy_4005]

EVERYONE, the term for the pieces of track at Rochelle is DIAMOND, using it will help avoid confusion, and I believe that that IS the term real railroads use. I have nicknamed Rochelle the "QUAD DIAMONDS" because of the track there.

Flangeways on diamonds or turnouts have to be there of course, but the flange itself should never be called on to support the car, real or model. there will always be some noise and unsmoothness when the wheels have to cross a rail, but the goal is always to minimize that. Less noise, less bounce, fewer derailments at frogs.

Frogs can take a real pounding, and get worn out in a hurry. It happens all the time on the real railroads. A couple of summers ago, my daughter and I watched as a track repair crew welded a new chunk of steel into place on the point of a damaged frog. This was a temporary fix and has probably been redone since, but this spring they will replace the entire turnout.

Frog damage can even happen on models, though most people don't run their trains that much. It did happen at the mall display on a few frogs.

As for rough and uneven track, I would think that it wolud not as big of a problen on tabletop type permanent layouts, but there will always be floor runners and of course KIDS.[:D]

[jkerklo]

Dave,

There is an excursion/dinner train that runs year 'round on the Tennessee Pass tracks through Royal Gorge.

http://www.royalgorgeroute.com

I know a guy that knows the guy running the excursion. If you would like to use the track for handcar races, I might be able to make a connection for you. Sounds like fun. When would you start?

John Kerklo
TCA 94-38455
www.Three-Rail.com

[FJ and G]

John,

I often dream of being rich enough to purchase T Pass. I'd run a tourist line or at least have handcar races there. Would be a wild ride going downhill, esp. after a few beers.

[jkerklo]

Thanks Bob.

Crossing, of course.

I never knew rails and wheels were so complicated. Next time I can see a train and track up close, I am going look for the details you mentioned.

I have spent time up on Tennessee pass with a drink beer/take pictures of trains gang. The rails on a curve there seemed to be worn on the outside and I couldn't figure it out. Until one of the gang who had worked on the railroad explained that on a curve, the worn inside rail is moved to the outside of the curve to get more life out of the rail. Indeed, there was rail discarded at the side that was worn on both sides, and must have been the previous outer rail, that had once been the previous inner rail.

This makes sense once one understands the "pulling a train around a curve" concept.

John Kerklo
TCA 94-38455
www.Three-Rail.com

[Anonymous]

i feel pretty sure that if you made your tracks as level and smooth as the prototype does AND if you made your engines and rolling stock weigh as much (in scale of course) as the prototype does AND you make your turns as wide as the prototype does...

the choo-choos would stay on the tracks with them skinny little prototype flanges.

BUT...[:p]
our tracks are too rough and uneven, out turns are too tight and our rolling stock is too light and we need the big flanges to keep them on the tracks.

look closely at any scale model wheels, if you made them life size they would ALL look silly compared to the prototype. i own almost entirely postwar lionel and they all look silly next to the real thing. take a picture of your favorite toy train and superimpose it over a picture of the real thing in your photo editing software. whew!

[Anonymous]

Bob:

Thanks for that post. Very informative.

Elliot:

I'm with you on this one. I don't want to change the wheels. Maybe the couplers, but not the wheels.

Tony

[lionelsoni]

The thing at Rochelle is a crossing. A crossover is something else.

The normal flangeway depth is about 2 inches. You can often see wear on the bottom of the flangeway of a crossing frog. Most of the welding at crossings involves building up the rail at the inside corners of the frogs, where it gets beaten down by wheels going over the gap formed by the flangeway of the other track.

Prototype wheel treads are also conical, but not nearly so much as fast-angle wheels. It is a popular misconception that this is done to keep the wheelset centered on the track. Actually, it promotes a hunting behavior in which the wheels yaw back and forth. This does keep the flanges out of contact with the rails for most of the time, which is a good thing.

The real reason for conical treads is to provide more metal close to the flanges to allow for the greater wear there. When a wheel wears more-or-less flat, it is condemned. If you look closely, you can see that the rails are canted very slightly inward by the tie plates, by half the slope of a new wheel's tread, so that the rail wear is distributed evenly between the inside and outside edges by the mix of new and old wheels.

Most prototype wheels are 33 inches in diameter. Those on heavier cars are 36 inches. Those on low-slung cars are often 28 inches. I don't have a model here to measure. Anyone?

[FJ and G]

John,

No. It's a wonder they stayed on the unballasted, primitive tie tracks.

I recall reading memoirs of a Shay fireman (or engineer?) who declared that you could always tell when the train derailed because the ride suddenly felt smoother.

[jkerklo]

Were the wheel flanges on logging railroads larger. Those I have seen didn't stand out as oversized.

John Kerklo
TCA 94-38455
www.Three-Rail.com

[FJ and G]

I believe that in real trains, the flange is not much deeper than 1 inch. That's it folks, only one inch of flange on hundreds of wheels of rocking, rolling train that keeps it from plunging off the bridge into the great chasm.

Why then, with our deep flanges, do our trains derail much more frequently than the real ones?

---------------------

This discussion has become more prevelent in HO and 2-rail O, because the flanges in those scales are also oversized. Proto48 and Proto87 has become a thriving subculture of modelers who increase the fidelity of their trains, including the flange size. They are very careful with their trackwork.

[Big_Boy_4005]

Now that I have taken some time to think about this, one of the reasons the flanges are so large has to be the fact that the head of the rail on traditional track is ROUND, as eZAK originally noted. While other more realistic track styles have been around for a long time, O and 027 styles will probably NEVER go away, and neither will the large flanges. The large flanges allow the trains to continue to stay on the rails long after scale type wheels would have derailed, making them more forgiving on rough track.

Wheels on N and HO scales as well as 2 rail O also have oversized flanges, though theirs are not nearly as grotesque as those of 3 rail O. The NMRA has been working on wheel contours for years, and as track quality has improved, flange size and wheel shape have moved closer to prototype.

There is a movement in both HO and O for what is called FINE SCALE though this is not the standard that manufacturers produce to. Replacement wheel sets are made and used by a growing number of serious modelers. This would be an acceptable option for 3 rail, except for fact that when cars change owners, they may need their wheels changed back. Beside, there is no easy way to change locomotive wheels.

Real railroad wheels actually have very small flanges, as they don't have to worry about BOUNCE, the way models do since they are so heavy. Real railroad wheels have come in a variety of sizes over the years, though they are pretty much standardized now. I'm not sure of the actual dimension.

Finally, these trains were originally intended for children, and the large flanges helped kids get the trains on the track. Even American Flyer S gauge has large flanges and it too is considered a "TOY" type train.

Do we really want to change this distinctive feature, this tradition that has been with us for so long? Personally I have come to love, accept, and even appreciate the large flanges over the years, and have no desire to change. I can get trouble free operation from less than perfect track as a result of this detail, and consider it part of what makes 3 rail different and fun. The bottom line is, if anything needs to be fixed to make things run better, it should be the track first, not the wheels. (Sorry if I read more into this question than you intended Pat.)

Remember, A horse, designed by committee, is a camel.[swg]

[jkerklo]

Thanks Tony,

I had never realized that the wheels were fixed to the axles on the new cars. I have to think a bit to see if I like it or not. Postwar wheels do wobble, that would solve that.

Prototypical wheels are fixed on axles; curves do generate a lot of rail wear, which implies pulling friction. Interesting.

You are mostly right about prototypical wheels not riding on flanges, but for an exception see the Rochelle webcam on this website.

There is a double track crossover and there has to be gaps in the track to clear the flanges of the opposing train.

Must be a maintenance nightmare. I have frequently observed trucks parked by the crossing, with welding flashes coming from the rails area.

John Kerklo
TCA 94-38455
www.Three-Rail.com