I recently experienced a weird short on my club layout, which, after a long investigation, was attributed to a brand new Fox Valley Models (FVM) boxcar where one of the axles was fully conducting; of course this is not supposed to happen as their wheelsets are fully insulated, but s... happens even after quality control.
Anyway, I had to replace the said axle, and there began my chemin de croix (French for "way of the cross" or laborious exploration) to figure out just how to do this. How do I know the proper axle for that car?
Car manufacturers are absolutely silent about it and even FVM (as both a car and wheelset manufacturer) does not indicate which wheelset to use for its cars.
So, I had to conduct my own investigations, which I'm sharing with you below. I hope that you will find this useful.
Wheelsets are available in a variety of diameter and axle lengths; of course both are important when you want to replace a wheelset. The most frustrating is the axle length as this can make a difference in the truck, though such differences are really minor (you'll need a caliper).
So here is the summary of what I've found from various sources:
By length (non exhaustive):
0.540 inch: Micro Trains; Athearn; FVM
0.553 inch: InterMountain; some Atlas
0.563 inch: Con-Cor; some Atlas; Bachmann; Kato
0.573 inch: Arnold-Rapido
Information courtesy of Streamlined Backshop
Arnold-Rapido - 0.573 in
Athearn - 0.540 in
Atlas - 0.540 in, 0.553 in, 0.563 in
Bachmann - 0.560 in
BMLA - 0.540 in
Con-Cor - 0.563 in
Deluxe Innovations - 0.553 in
Exactrail - 0.540 in
Fox Valley Models- 0.540 in
Intermountain - 0.553 in
Kato - 0.563 in
Lima - 0.549 in
Micro-Trains - 0.540 in
Model Power - 0.567 in
Rapido passenger - 0.526 in
Rivarossi - 0.549 in
Roundhouse - 0.549 in
Tangent - 0.537 in
Walthers - 0.545 in
If you'd like more information about wheels dimensions, please refer to this NMRA RP25 standard.
Here is a link to the N scale wheelsets featured on TroveStar.