Flanges, To big OR Is Wheel to Small!

[Anonymous]

There was a discussion on wheels & standards on the OGR Standards Forum. I'm no expert, but I'll repeat the little I know.

The current tapered wheels are called "fast angle wheels." They first appeared during the Lionel MPC era. That's when Lionel went from independent wheels in their trucks to two wheels on an axle. The forces of going through a curve are supposed to shift the wheels in such a way that the narrower diameter part of the inside wheel rides the rail, while the wider diameter part of the outside wheel rides the outer rail. This causes the inner wheel to spin faster, and the outer wheel to cover more ground, allowing the car to go through the curve easier & with less resistance.

If you push a car with fast-angle wheels down a straight into a curve & then do the same with an older PW car, you'll find that the newer car travels farther. Assuming you push with the same force, etc.

Having the train ride on the outer rim of the flange isn't strictly necessary from a theoretical standpoint, since the real things don't do this. I don't know why toy trains do, but they shouldn't have to. Maybe if you lay your own turnouts you can prevent that from happening.

Finally, I believe that 2 railers use wheels with a more prototypical cross section, but there's a very good chance I'm wrong about that.

Tony

[jkerklo]

I have been wondering about flange depth and slanted wheels myself.

Noting that most switches and crossovers have some places where the wheel must ride on its outside rim to make it over gaps:

Has the depth of the flange changed over time? It appears to have been deeper for the prewar sheet metal wheels, but has it changed from postwar till now?

Is there a specification or standard? I have never seen any accepted wheel standards for O-gauge toy trains, yet wheel makers and switch makers have to cooperate or nothing would work. Are we still using standards developed so far in the past that they are a part of toy train history?

Whose idea was the slanted/tapered wheel? The only reason I can see is that wheel spacing on the axle can be sloppy.

I use some 711 switches (prewar, O72) on my layout. New cars "bump" more going through the switch than postwar cars. Yet, I can't see any difference with modern Lionel O72 switches. Has anyone done a serious comparison?

I would find any comments useful.

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

[Big_Boy_4005]

Well Pat I can post very fast, I saw this within 4 minutes of your posting it. The truth is I DON'T KNOW the answer to this, and I think it's a very interesting set of questions.[:D][;)]

[eZAK]

Now we all know that flanges are far larger than any proto type known.

AND

We also know that they were made that way for tight (0-27) turns
and rounded over rail.

Now what I am unsure of is what should be the scale diameter of the outside edge of the flange?

AND

What is the outside diameter of the wheel itself?

The point being is could the flange be the right size diameter and the actual inner wheel be too small?


On another note, Are large flanges really needed anymore?

Isn't it more of a weight issue?