Coverting MTL, Atlas, Roundhouse and Atheran Rolling Stock Wheel Sets

[nkalanaga]

Mike:  That's me.  I like to run trains.  The wheels don't really stand out while the train is moving - as long as they stay on the track.  I don't want pizza cutters, or the over-wide wheels of 50 years ago, but most of today's look fine to me.

For photographers, or model builders, I can see scale appearance being more important.

[Maletrain]

Has anybody run the ESM wheels in plastic trucks for extended periods and then checked their rolling friction?

I ask because I too have found that the ESM wheels roll much more freely than anything else.  And the reason seems to be the axle points are "pointier" than any of the competitors.  (Of course, smooth machining is also required).  I am wondering if the smaller bearing surface of the ESM wheel points will wear the plastic mating surface to the axle point contour after extended use, which would tend to make it have larger surface contact area and might increase the rolling friction.

But, friction is a hard thing to deal with by theory.  So, my question is about experience.  Perhaps people who like to run long trains at shows can tell me about how the combination of ESM wheels and Delrin trucks behaves after multiple days of running for hours?

[bbussey]

I would think that a ton of hours would need to be logged before there is any discernible difference in performance.  You have a small contact region coupled with dis-similar materials in the stainless steel metal axle and the acetyl plastic sideframes.  This would apply to all high-quality machined wheelsets, not just ESM.

[Maletrain]

I would think that a ton of hours would need to be logged before there is any discernible difference in performance.  You have a small contact region coupled with dis-similar materials in the stainless steel metal axle and the acetyl plastic sideframes.  This would apply to all high-quality machined wheelsets, not just ESM.

Bryan, I am hoping you are right about that, since I have installed a bunch of ESM wheels to minimize the rolling friction on a long train that I am planning to run for long periods at club open house events.  So far, I have not detected any change in the rolling properties, but I have only run those cars for about an hour, total, with the ESM wheels. 

On some used cars I have bought, I have seen some trucks that have wear impressions of axel points in the truck bearing surfaces.  I found those while investigating the poor rolling qualities.  At the point where I received them, they usually did not have the wheels that made the impressions - apparently the sellers took the "good wheels" out and put some plastic pizza cutters or other cheap wheels in before the sale to me. So, I have no idea what caused the wear impressions - I just know that something can do that.  (I doubt they were your ESM wheels, though, given the dates of things.)

Anyway, that is why I am asking for actual experience with long-term running with ESM wheels.  The axel points are noticeably sharper angle than any others, which seems to be why they roll with less friction.

[bigdawgks]

I think there are way too many variables that affect rolling resistance to be able to derive any conclusions about the wheel sets alone. In my experience, when a car with metal wheels has high rolling resistance it's either because something is rubbing on the axle (usually the coupler box) or the truck bearings are inconsistent or deformed. The latter is more likely to occur than you might expect. I've seen quite a few truck designs where the plastic walls of the bearing are thin enough where they can bend when trying to insert a metal axe point. This can cause enough deformation to affect rolling resistance.

[bbussey]

On some used cars I have bought, I have seen some trucks that have wear impressions of axel points in the truck bearing surfaces.  I found those while investigating the poor rolling qualities.  At the point where I received them, they usually did not have the wheels that made the impressions - apparently the sellers took the "good wheels" out and put some plastic pizza cutters or other cheap wheels in before the sale to me. So, I have no idea what caused the wear impressions - I just know that something can do that.  (I doubt they were your ESM wheels, though, given the dates of things.)

You note that on these second-hand acquisitions, plastic wheels were swapped in allegedly to replace metal axle wheelsets. I posit that had the metal wheelsets remained, the performance would have been close to what it was when originally installed. Even with wear inside the bearing cups, the contact surface between the metal and plastic would be far less than with plastic axles and plastic bearing cups and therefore more frictionless and better performing.

[Maletrain]

Bryan, I didn't mean to imply that the bad rolling effects were from putting plastic wheels into trucks with worn axle cups.  Those cases were just junk wheels somebody had put into cars they were divesting themselves of.  The rolling problems were sometimes even that the axles were the wrong length.  It is just that the rolling issues are what got me to look at the cups in the trucks.  So all I know is that wear sometimes occurs there.  Putting in ESM or Fox Valley wheels usually got them to roll much better, although I did trash a few sets of trucks where I couldn't seem to find an available axle length that worked well.  Having gotten old plastic wheels with steel axles that had rusted ends, it would not surprise me if something like that was the cause of the wear that I found.

I am only thinking about this because I am thinking about a train that might end up running more than 36 hours per year, with various individual run times in the multiple hours range.