eBay Buy-it-now Photo Comment

[Roy]

Thanks, Wayne. Really good photos. I still can't believe there's no allowance for turn differential. Do you get a lot of wheel squealing on sharp turns?

[webenda]

Roy,

Pushing the car from tangent track into O-31 curves I can feel more resistance but the increase is minimal [opinion.]
There is more wheel noise in the curve, but no squeal that I can detect.
Real railroad wheels squeal loudly in tight curves:=> https://youtu.be/Ly1nREJ6l8k

Cars with this new truck/wheel design roll down the slightest gradient on tangent track, then stop in an O-31 curve of the same gradient.
However, the fast angle cars do the same thing. It just takes more gradient to get them started on tangent track.

It would be an interesting experiment to compare a car with wheels that spin on their axles in a curve to the other wheel/axle styles.

[Roy]

Roy,

Pushing the car from tangent track into O-31 curves I can feel more resistance but the increase is minimal [opinion.]
There is more wheel noise in the curve, but no squeal that I can detect.
Real railroad wheels squeal loudly in tight curves:=> https://youtu.be/Ly1nREJ6l8k

Cars with this new truck/wheel design roll down the slightest gradient on tangent track, then stop in an O-31 curve of the same gradient.
However, the fast angle cars do the same thing. It just takes more gradient to get them started on tangent track.

It would be an interesting experiment to compare a car with wheels that spin on their axles in a curve to the other wheel/axle styles.

You used to have to oil every wheel on every postwar car. Plus, they weren't as low friction. I'm surprised no one has thought to use small axles with a slippery plastic bearing - like used on Hot Wheels cars. The needlepoint bearings are similar, but don't allow for differential on turns, and three rail uses the sharpest turns of any model train. The obvious solution is to use HW-type bearings on all wheels.

If you want to keep the needlepoint bearings, you could fit one wheel per axle with a delrin or oilite bushing insert, so as to allow that wheel to turn on it's axle. Since the axle is always turning with the fixed wheel, the wheel bushing - fitted wheel will only roll on the axle on turns.

This will allow you to use any wheel profile you like, although the fast-angle wheels will always have a wedge effect on the track rails.

[chuck]

Hot wheels don't pick up electricity through there wheel's/axles. Any solution to allow differential turning of the wheel set will have to take this into consideration.

I've never noticed any noise or binding but I haven't run the cars on anything tighter than O-36 and usually on O-72.

[Roy]

Hot wheels don't pick up electricity through there wheel's/axles. Any solution to allow differential turning of the wheel set will have to take this into consideration.

For cars that require electrical pickup, you can use oilite bearings, rather than delrin. To me, it looks like Lionel is using oilite bearings on Wayne's new car:

I've never noticed any noise or binding but I haven't run the cars on anything tighter than O-36 and usually on O-72.

Without differential action, there will be skidding of the wheels on turns. The tighter the turns, the more skidding.

[webenda]

I've never noticed any noise or binding but I haven't run the cars on anything tighter than O-36 and usually on O-72.

I just ran the rolling downhill experiment again with cell phone video cam picking up the sound. Neither my ears nor the camera detected more noise in the curve. The car did stop in the curve requiring a steady push to continue noise evaluation through the curve.

Now that you have given me cause to evaluate my original tests, I have to question the rolling resistance in curve test also. The problem with my set-up--I eyeballed the gradient. Not scientific enough to take opinion bias out of the equation.

Thinking about the gravity powered rolling test, flanges were observed rubbing the outside rail. I imagine if the car was pulled through the curve by a locomotive, the flanges would rub the inside rail. A lot of variables come into play during a rolling resistance test.

To me, it looks like Lionel is using oilite bearings on Wayne's new car:

I want to say, "I am sure they are Delrin, Roy" but now that Chuck has me skeptical about my rolling tests, maybe I should not be sure without some kind of analysis of the material.

Edit 1: Changed "Derlin" to "Delrin." Was not a typo, I have been mispronouncing it since it was invented.

[Roy]

Wayne, I know I asked about wheel squeal, but I'm personally only interested in rolling performance.

FWIW, I'm guessing the bearings in your new boxcar are iron-based oilite, and so would be ferromagnetic.

[rogruth]

Is this important to the average three rail model railroader?
Remember I said average not someone who is running on a display layout several hours a day non stop.
Bob Turner has told us about the locos that he works on for a local club. I don't think I have seen any
reports similar to his concerning rolling stock.
Personally my cars probably run about 20 minutes a week while locos get a little more. Neither do I run
long trains as many clubs do. I do agree that the needle-point axles seem to roll better and I do
understand about the angled wheels compared to flat but wonder how much difference it makes.
I have a few of the wheels that turn on the axle and think that they develop some wobble.

[Roy]

Is this important to the average three rail model railroader?

No. On OGR, I was damn near burned at the stake, for questioning the canon of fast-angled treads.

[chuck]

There was an article in Model Railroader way back when Fundimensions took over the product line (like 1970). I think they were interviewing someone in regards to Toy Fair. The guy explained why they changed the truck design and came up with needle point axles and fast angle wheel treads. While it doesn't look like the real thing, it actually "tracks" better, especially on O-27 curves. These are after all toys and not scale models.

[CWBurfle]

There was an article in Model Railroader way back when Fundimensions took over the product line (like 1970). I think they were interviewing someone in regards to Toy Fair. The guy explained why they changed the truck design and came up with needle point axles and fast angle wheel treads. While it doesn't look like the real thing, it actually "tracks" better, especially on O-27 curves. These are after all toys and not scale models.

I remember that article. There was also a nice article when the baby Madison cars were developed.

I don't remember where I heard/read it, but back then there was also a story going around that the fast angle wheels really came out of the need for creating a "draft angle" so the wheels could be ejected from their mold.

[Roy]

The story is also in one of the TM books. MPC/Lionel engineers wanted to fix the wheels to the axles. The fast angle tread allowed them to do this, as the fast angle creates differential on curves. The larger inside of the tread moves up the outside rail, and the smaller outside part of the tread runs on the inside rail. Think of how a cone rolls on a flat surface, and you get the idea.

Real railroad car wheels are also slightly conic. I'm sure Wayne can calculate the ideal track curvature that corresponds to the conic angle of the treads, where they get the ideal differential action. Anyway, the sharper the turns you have, the more steeply conic the wheel treads must be.

As we can see now, the real improvement from 1970, in terms of friction reduction, was the needlepoint bearing.

[webenda]

I'm sure Wayne can calculate the ideal track curvature that corresponds to the conic angle of the treads, where they get the ideal differential action.

Of course, anyone can do that, it is basic algebra. Average performers get introduced to algebra in the eighth grade.

Those

… flat treaded wheels…

on my 6-17767 are not flat.

They have a diameter of 0.681 inches on the outer part

681.jpg (164.93 KiB) Viewed 6341 times

and 0.691 inches on the inside (near flange.)

691.jpg (168.23 KiB) Viewed 6341 times

Algebraic answer: O-127 curves.

[webenda]

FWIW, I'm guessing the bearings in your new boxcar are iron-based oilite, and so would be ferromagnetic.

No more guessing, I tested the materials with a magnet.

The wheels, axle, bolster and coupler frame are Ferromagnetic. See "magnet test 1."

magnet test 1.jpg (240.28 KiB) Viewed 6336 times

The polyoxymethylene (Delrin) conical pocket bearings, zinc side frames and coupler are Diamagnetic. See "magnet test 2."

magnet test 2.jpg (141.53 KiB) Viewed 6336 times

Magnet test 2 only revealed the materials were not ferromagnetic. Had to look them up to see if they were paramagnetic or diamagnetic (or maybe weakly ferromagnetic.)

Edit 1: Changed "polyoxymthylene (Derlin)" to "polyoxmethylene (Delrin)".
Edit 2: Actually did what I said in "Edit 1" this time!

[Rufus T. Firefly]

The polyoxymthylene (Derlin) conical pocket bearings, zinc side frames and coupler are Diamagnetic. See "magnet test 2."

Delrin, maybe?

Polyoxymethylene?

Acetal, maybe?