Metal vs. Plastic Wheels on Rolling Stock

HA Watash, you funny guy! I always thought we most of the time thought about the same on subjects... Anyway, I must say, I too am not to fond of KD trucks of the newer ones! However the older ones were more of the Central Valley style and that I prefer! The Central Valley out preform most of the sprung trucks ever made! I can get mine to flex and fluctuate durring a single run by changing speed on a train in a curve... Where the KD trucks I've bought doesn't! So...

Just guys don't take me the wrong way tho.. I'm not connected with any of these companies, or anything or fond of ALL sprung trucks.... I'm just apraising Central Valley trucks! They have never failed me as the other ones that I've tried, through trial and error...

 

One point I didn't make too clearly.

Over the years I found that even sprung trucks that have plastic wheels, will derail quite easily, just as the rigid plastic trucks do.

It is the plastic flange that is able to get a "bite" on the sharp edge of a rail and then is able to climb up over on top of that rail where it will then fall off on the outside pulling the other wheel off its rail to fall into the gauge.

It is the same action as trying to slide a razor blade along a piece of plastic. Pushing with the sharp edge down against the plastic surface, the blade "bites" into the plastic (the same as the blade on a carpenter's "plane" does to slice a shaving of wood), but when pulled along the other way, the sharp edge just slides over the plastic. Now if you remove or round off the sharp edge on the razor blade, it will slide along the plastic in either direction.

I have never had a brass wheel flange perform this way in the last 40 years or so.

I looked for ways to fix this problem.

One "fix" I have tried, is 180 and 220 grit emery cloth, no good.

So I tried to run a diamond finger nail file along the inside edge of both rails on new track to knock off this sharp edge.

If I get a tiny angle between 30 and 45 degrees for about .015" down from the top of the rail head, I figured, the plastic wheels would stay on the curves better, but this was not the case.

Why didn't it work? Thinking it out, I realized it was the "surface finish" of the rounded or chamfered area that was still presenting something to give the flange enough purchase to climb up over the rail head. So I tried something else.

(My Dad always taught me to be resourceful, think it through.)

So, I tried filing with a Nickelson fine finishing file (6"), the cut of its teeth leaves a more slick smooth surface than the diamond file does.

This worked! I felt like a Hero!

My considered opinion now, is that the diamond file (as does 180 grit emery cloth), leaves a row of tiny ridges or grooves (like a plowed field) which still allows a plastic wheel to obtain enough "bite" to climb up and over the rail head.

Now I "slick off" the inside edge of both rail heads of any new, (and some old) track before I try to lay it.

With that bit of effort, I no longer have derailing problems, even when backing long strings of passenger cars through turnouts or 30" radius curves. (What happens on tighter curves, I don't know, but I suspect it would help.)

"Its the attention to detail that makes the finished product a thing of value." - An old Master Craftsman's advice. (I took it, and use it.)

[ 04 June 2002, 17:39: Message edited by: watash ]

 

I'll have to agree with SP, in my expierience sprung trucks range from just a maintainence headache downwards to impossible to keep on the track! The better ones I have used are the ones on my brass passenger cars, but if you need to remove a wheelset to fix a gauge issue or to change wheelsets it's a NIGHTMARE to get all those pieces back together! Even worse are the sprung freight trucks I've dealt with wich never did stay on the track and also tended to do other strange things like pick points fairly regularly. For my money, the best and most reliable combination is Proto wheelsers in an Athearn truck. Some of the others look better, but I haven't found anything that runs better.