--- In STMFC@..., "Gene Green" <bierglaeser@...> wrote:

I just replaced the wheel sets in a pair of Kadee Vulcan trucks with
narrow-tread wheel sets (should I write wheelsets instead?) from
Intermountain. The replacement wheel sets appeared to have an axle
length very similar to the old Kadee axles. I did not measure them.
There was quite a bit of side-to-side movement possible with either
wheel sets. This did not seem to affect the rolling qualities at
all. Appearance was improved though.

Wheel sets from Reboxx with longer axles would take up some of that
side-to-side slack but is that important? Given the cone shape of
the bearing and axle tip, wouldn't the axles tend to be self-
centering?

Gene,

It's important if you intend to use any of the smaller "scale size"
couplers, as these couplers have a smaller "gathering range", and are
therefore more prone to miss if the car bodies aren't centered on the
track, with an attendant decline in coupler reliability. I know logic
would suggest that the tapered axle ends would keep the cars centered,
but in reality the centering forces are small compared to the other
forces acting on cars in a train. Years ago, when I was experimenting
with the old Kadee 711 "Old Timer" coupler I noticed this; two cars
could be uncoupled on a tangent, one of the cars then used as a
"handle" (idler) to push into industrial trackage, and when the
original car came back out, it would not re-couple to the car left on
the main. The foces acting on the car as it curved through the
diverging routes of turnouts were enough to make the carbody crowd to
one side, and there was not enough running on the tangent to make it
self center again. The solution was to equip all the test cars with
brass axles custom make to fit each car, and then coupling reliability
increased dramatically. Unfortunately, the couplers had other problems
that were not so easily overcome, and my experiment ended.

Your best course of action, if you want to use both near scale wheels
and couplers, is to invest in a Reboxx sampler set, and closely match
the axle length to the trucks.

Has anyone experimented with a narrower (shorter) replacement truck
bolster for Kadee trucks? Most model trucks apppear to me to be
wider than if a prototype truck was literally scaled down to HO or, I
suppose, any other scale for that matter. Couldn't slightly narrower
bolsters be machined from brass or something?

Use Accurail trucks, which are very close to scale width (Intentional
plug :-) I'm sure Andy Reichert will chime in about his scale width
Kadee trucks he is offering for P:87, which I believe he also offers
with .088 wide semi scale wheels.

Dennis