Adjusting wheel gauge

[Desertdweller]

Probably the most common problem encountered with N-scale rolling stock is out-of-gauge wheel sets.  This is most often encountered on older pieces which were frequently out of gauge even when new.

Newer cars usually avoid this problem by use of a plastic spacer on the axle, or by molding the entire wheel set as a solid piece of plastic.  However, there is an easy and quick way to correct it.

To do this fix, you'll need an accurate way to measure back-to-back wheel spacing.  I use a MicroTrains coupler adjustment gauge.  Other tools exist for this purpose, such as a stainless steel rule with spacing marked.  You can even make your own gauge if you have an accurate wheel set to use as a guide.  Cut two narrow notches in a straightedge at the correct spacing for the wheel flanges to fit into.  As this tool will not be taking any strain, you could even use stiff plastic sheet.

Begin by fitting the gauge against the wheel sets while they are still on the car.  You will quickly be able to identify any that are out of gauge.  While you may find some that are too wide, most of the time any that are wrong will be too narrow.  If you find any out of spec, take a second check 180 degrees from where the first check was made.  A deviation from the first measurement would indicate a bent axle or wheel.

Remove the problem wheel set from the truck.  Since virtually all N-scale trucks are made of a slightly flexible plastic, you can gently spread the frame with a thin-bladed screwdriver between the wheel and the side frame, and the wheel set should pop right out.

Next, identify which wheel is the insulated one.  It will have a black plastic center.  Some cars have both wheels insulated.  The insulated wheel will be the one to adjust.

Grasp the axle with a needle-nosed pliers.  Take a regular slip-joint pliers and adjust it so the jaws don't close completely.  With this pliers, gently hold the insulated wheel (so you don't damage the flange).  Slowly pull the wheel toward the end of the axle until the wheel checks true with your gauge.  If you pull too hard and the wheel comes off, don't worry.  It can be put back on easily.  Check the gauge spacing at two points 180 degrees apart to be sure everything is still straight.  If the gauge is too wide, gently push on the face of the wheel.

This works on both freight and passenger cars.  Cars such as Atlas use a thin metal axle, Bachmann uses a thicker axle, but they both can be adjusted the same way.

If you wish, you can ensure the wheels stay as adjusted by putting a small drop of glue on the back side of the wheel where the insulation meets the axle.

Tools you will need:
Wheel gauge (purchased or home made).
Needle-nosed pliers.
Slip-joint pliers.
Small thin-bladed screwdriver.
Optional: glue (I use Superglue Gel).

Les