Crystal River Products Wheel Interference Tester

Reviewed by Chris Lane/photos by the author

I am a tool and gadget guy and every once in awhile I come across a model railroading gadget that causes me to think, “Dang! What a great idea.” This new tool from Crystal River Products is one of those.

One of the neat things about narrow gauge equipment is all the piping, truss rods, brake gear and underframe sills slung down close to the rails. Unfortunately, those very items make operation on tight model railroad type curves a tricky proposition. I built much of my former On3 car fleet while away at college in Durango, Colorado. Before playing in rock bands and drinking fermented beverages took up all my non-school time, I enjoyed building kits in my dorm room. Need a look at a car detail? No sweat, just run down the hill to behind Safeway, where the D&RGW had conveniently parked a long string of freight cars for me to examine. I started to add every underframe detail I could see, including frame splice joints, nut-bolt-washer assemblies, piping, clevises and so on. It made for some impressive-looking detail under the cars. After I graduated and joined the Denver O scale club, I found that all that detail made the operation of the cars erratic. I ended up trimming piping, bending brake gear, cutting back some sills and doing other fixes through trail and error to allow these cars to operate on even the generous radiuses of the club. I figured out that you could have full detail, or you can have reliable operation, but you can’t have both.

Spring ahead almost twenty years and I am working almost exclusively in On30. I still like detail as much as I ever did, but I like operation even more and as a rule the radiuses I use in On30 are tighter than even my old home layouts in On3. So same dilemma as before; how to maximize the detail, but minimize the radius a car will turn and maximize its operational reliability. This has become all the more critical as a number of models have become available in both On3 and On30 configurations.

Crystal River Products PO Box 598 Conifer, CO 80433 Wheel Interference Tester MSRP $15.00 plus postage

Enter the Wheel Interference Tester. It is a clear, acrylic plastic with two wheel flange grooves cut into it with a laser, at a set radius. Currently Crystal River offers 18”, 24” 28” and 36” radiuses in On30 (HO) scale. To use the tool, simply place the car on the tester and wiggle it until all the flanges drop into the grooves. Then, pull and push the car by its coupler back and forth. Turn the car 180 degrees and repeat. If the car stays in the grooves, it is ready to go on your layout. If it derails, or doesn’t roll smoothly in the grooves a bit more work is needed. Now place the car upside down on foam or blocks, and again put the flanges in the grooves. Roll the tester back and forth and you should be able to determine fairly quickly by looking through the clear tester where the interference is occurring. The tester allows you to see the wheels or truck sideframes hitting detail parts, truss rods or center sills as well as finding sticky wheelsets or excessive axle play. Also, there is a centerline etched into the tool so you can check coupler swing. Honestly, this is where you can head off a great deal of trouble. I find quite a few cars that have plenty of truck swing to make it through tight radiuses, but it is the coupler swing limit that ends up pushing or pulling a car off the curve.