Please Expand on This Statement in Italics...

What "wheels" are we talking about, i.e. model train wheels, Hi-Rail wheels, real railroad wheels? For what it's worth, real railroad wheels are NOT "flat"!

i’m pretty sure they mean the wheels are beveled to have a smaller contact patch hence less friction, and lower drag. apparently in this case it didn’t work well enough to justify its cost.

@Signalwoman posted:

i’m pretty sure they mean the wheels are beveled to have a smaller contact patch hence less friction, and lower drag. apparently in this case it didn’t work well enough to justify its cost.

Lionel, Williams, MTH, & Menards are still using "fast-angle" wheels, aren't they?  All my new Lionel has them just as in 1970.

@ADCX Rob posted:

Lionel, Williams, MTH, & Menards are still using "fast-angle" wheels, aren't they?  All my new Lionel has them just as in 1970.

Probably cost prohibitive to retool back again.

Well, looking at my contemporary Lionel and MTH rolling stock I have to say the italicized statement is just plain false. Everything I have has "fast-angle" wheel-sets. 

Seems like I recall reading that the fast angle wheel, needle point axles were designed to reduce the friction we all tried unsuccessfully to deal with as kids.  You could oil the axle where it met the truck and oil the axle where the wheels mounted but the stupid thing still had so much friction that you could not pull anything that looked like a real train.  By creating the needle point axle the friction problem was solved.  The fast angle wheel allowed the wheel, which was no longer independent from the axle, to go around a curve.

I just looked at a number of cars, most had fast angle wheels and needlepoint axles.  However, the recent Lionel sound boxcar has bronze bearings and flatter wheels, so maybe it's a recent change.

perhaps they just meant newly designed wheels, as in, all wheels designed from that point would no longer be angled. older designs still in use would still have the fast angle. id image they wouldn’t want to retool the whole line at once. 

i don’t think it would matter much on tubular track, as the contact patch of the rail is so narrow, but on more prototypical stuff i could see it making a difference, especially in curves.

I can't imagine why it's a big deal with rolling stock.  I can tell you for sure the cars with the needle-point axles and fast angle wheels have MUCH less rolling resistance than cars with flat shafts and bronze bearings.  It stands to reason, given the fact that real prototypes also have angled wheels to reduce rolling resistance and slipping on curves.  Obviously, the weight precludes the needle-point axles.

Try this experiment.  Take a car with flat wheels and normal bearings, make sure it's lubed to give it's best performance.   Put a car with fast angle wheels and needlepoint axles in front, but don't couple them.  Give them a nice push around a gentle curve and I'll be surprised if the the car in front doesn't roll farther than the one in back.  Now swap their positions and do the same thing.  The car in back will be right on the car in front when they stop.

What else are we looking for in a model train car as far as rolling down the tracks?

Fast angle wheels and the needle point axles are a tremendous improvement over the postwar type trucks.   I think it was between 8 to 10 cars or more of mpc versus 1 die-cast postwar car like a 3520 when i compared them.   I pretty much don't run anything that's not fast angle/beveled wheels.

If i had flat spots on my wheels like the real railroad, I'd really be in trouble.

Fast angle wheels were introduced when wheel and axle design was changed to a rigid assembly. Previously, each wheel would rotate on the axle independently.

When a wheel/axle assembly goes around a curve the outer wheel travels a longer distance than the inner wheel. When each wheel moved independently this was no problem.

But with flat tread rigid assemblies, one wheel would drag slightly around the curve since each is traveling a different distance.

The fast angle design allows the outer wheel to ride up on the higher part of the tread effectively increasing it's diameter to compensate for the extra distance it travels. Thus, there is less drag overall on the wheel set.

Prototype wheel axle assemblies work the same way due to the curved fillet between the tread and flange. Since prototype curves are so wide, the the angle does not have to be severe as on the model.

Jim

Maybe @railbear601 can explain where his information came from? Just opinion?

Independent wheel rotation would eliminate the need for a continuous spinning axle.  the fast angle wheel as was said does compensate for the travel distance which tends to keep the wheels on the track. It is a simple easy to manufacture solution. 

I don't know of any toy or train cars, except the Automotion vehicles that have independent front wheel rotation. This would require an independent wheel supporting (short) axle for each wheel.

Here is a photo of a bench made out of a prototype wheel.  It gives a good idea of what a real wheel looks like.  The tread appears to me to be almost flat.  NH Joe

@New Haven Joe posted:

Here is a photo of a bench made out of a prototype wheel.  It gives a good idea of what a real wheel looks like.  The tread appears to me to be almost flat.  NH Joe

It looks almost flat, but it's not totally flat.  Since prototype curves are much wider than model train curves, the angle is very small on the wheel, but it is there.  An Internet search will turn up tons of references as to the taper and why it's there.

@AlanRail posted:

Independent wheel rotation would eliminate the need for a continuous spinning axle.  the fast angle wheel as was said does compensate for the travel distance which tends to keep the wheels on the track. It is a simple easy to manufacture solution.

Simple solution?  I think not!  Imagine how expensive it would be to develop independent suspension for the weights that railcars carry!  There's surely a very good reason this has never been done, and I suspect it's a question of economics!  The present system of tapered wheels with fixed axles works very well.  The tapered wheels also actually help to gently steer the car around the curves as centrifugal force pushes it to the outside of the curve. 

Don't fix stuff that ain't broke!

@gunrunnerjohn posted:

It looks almost flat, but it's not totally flat.  Since prototype curves are much wider than model train curves, the angle is very small on the wheel, but it is there.  An Internet search will turn up tons of references as to the taper and why it's there.

Correct. Not only are real railroad wheel treads tapered (generally 1 in 20 taper), the trails are also "tilted" inward, since the tie-plates that the rails rest on, are made with a taper. Thus, the tie-plates have a definite direction when placed on top of the tie.

BART (probably the noisiest transit system) has flat wheels.......they finally decided to reshape to conical.

They are claiming a 15 to 20 Dba reduction in noise.

BART Headache Howl

Makes sense the rails would have a slight tilt, that helps with the effect of the wheels.

I did read about BART changing over to tapered wheels, given California's excellent record with railroads, it stands to reason they'd do something lame like flat wheels.