For years I’ve looked at the pictures of early logging in books such as Michael Koch’s "Steam and Thunder in the Timber" and thought it would be fun to take a break from my usual Sn3 modeling and fiddle with a diorama or small layout which captured the feel of those pictures. The motive power shown in the pictures was usually small. For over 25 years, I’ve installed sound in all of my locomotives and would want sound for a new project like I envisioned. Good low speed running is also a requirement for my locomotives. It seemed to me a small O scale geared engine would meet these requirements. Until recently that meant buying brass. Since this anticipated small layout was intended to be only as a sideline from my usual modeling I didn’t want to spend a lot on it. That ruled out brass. The advent of the Bachmann On30 Shay provided a relatively low cost alternative to brass which also met all of my other requirements. I bought one.

Having the O scale Shay started me looking at other facets of my potential new railroad to be. Many of the prototype railroads shown in the pictures were 36" gauge. I also found that there were lots of neat 36" gauge items such as trucks available. I decided that my new Shay should be converted to 36" gauge.

My decision to regauge my Shay from 30" to 36" gauge was reinforced by the appearance of Keith Wiseman’s instructions on his web article which is at: http://www.locopainter.com/SHAYCONVERSION.html

On30 gauge is actually On31.3" gauge or 0.650". It is necessary to widen the gauge of the trucks by only 0.100" to achieve 0n36" gauge. Keith’s conversion method involves widening the gauge by removal of 0.100" of material from the gears, reattaching the gears to the wheels with screws, spreading the wheels on the axle by the requisite 0.100" and then cutting clearance notches on one side of the truck sideframes. As I read through his procedure I could foresee two places I might have problems. I was concerned both about keeping the front and back faces of the gears parallel and of damaging the gear teeth while I was attaching them to the wheels with screws. I do suggest that you visit his conversion article. It has excellent photos of the trucks and gears which I found a handy reference.

After examining my Shay, I decided to increase the gauge of its trucks by 0.060" on the geared wheel side and by 0.040" on the opposite side. Using this method I avoided the need to cut clearance notches in the sideframes and of screwing the gears to the wheels. With one exception the only power tool used in my conversion was a Dremel tool. That one exception was a drill press. If you don’t have one perhaps you can get a friend with one to drill a hole for you. The only other tool which I think is almost mandatory for the job is a dial caliper to accurately measure depths and diameters.

Start the conversion by removing the trucks from the locomotive. The spoked wheel side of the trucks has a plastic plate which covers the center of the bolster. Snap this cover off and you’ll access a screw which holds the sideframe to the truck bolster. Remove this screw as well as the screw which attaches the sideframe to the top of the bolster. Before removing the top screw remember the relationship of the 0.010" bent phosphor bronze wires which are sandwiched between the sideframe and the truck bolster on both sides of the truck and are held in place by the top screw. These wires carry current from the trucks to the motor, They rub against a printed circuit board and if they’re deformed you may have problems with poor contact. Slide the brakebeams off of the trucks. They come off fairly easily.

After the wheelsets are out of the trucks, separate the axle halves. Then pull the final drive gears from the wheels. The gears are located by the protruding axle ends of the wheels and by two molded nubs on the back face of each gear which slip into two holes on the wheel. The two holes in the wheel are about 0.059" in diameter. A couple of mine were a little undersize. Run a 0.059" (#53) drill through the holes.

Cut a piece of 1/16" O.D. by 1/32" I.D. brass tubing about 1/2" long, and then reduce one end of it until it is a slip fit into the 0.059" hole. Press it in from the backside of the wheel until it is flush with the front face of the wheelweb and parallel to the axle. Use care with this piece because it will serve as a drill bushing for redoing all of the gears. Use a pair of flush cutters to nip just one of the nubs off of the back of a drive gear. File this surface smooth Slip the gear back on the wheel locating it with the protruding axle and remaining nub. Using the drill bushing drill an 0.031" hole in the backside of the gear where the nub was. Set your drill in the chuck so that it doesn’t go through the gear. Remove the gear and the drill bushing. Enlarge the hole in the wheel with a 0.063 (#52) drill.

Cut a piece of 1/16" brass tubing a just a bit longer than the thickness of the wheel web. An easy way to do this is to drill a slightly undersize hole in a piece of stripwood about the thickness of the wheel web, force the brass tube into it and then cut the tubing with a Dremel cut-off wheel. Insert the piece of brass into the wheel web so it is flush with the front face of the wheel. To aid me in getting the short piece of brass tubing started in the hole in the wheel web, I chucked a length of the 1/16th brass tubing in a pin vise and then stuck a longer piece of 0.031 music wire into the piece of brass tube.

I then slid the short length of brass tube onto the music wire and used the music wire to guide the short piece of brass tubing into the wheel web hole. Once it was started in the hole, I tapped it in with a punch until it was flush with the front face of the wheel web. I cut a short length of 0.031 music wire which I stuck in the hole in the gear with it projecting far enough from the gear to engage the brass tube in the wheel hole. I then cut the other nub off the gear. I installed the drill bushing in the hole in the wheel web which was still 0.059 dia. and reinstalled the gear on the wheel with the 0.031 gear pin sticking through the short brass tube of the wheel web.

This accurately located the gear so I could drill the second 0.031 diameter hole in the gear. I’d repeat the rest of the steps until I had the wheel - gear set with two steel pins driving the gear. After getting the hang of it while doing the first hole it’s really pretty fast. Repeat these operations again for the other geared drive wheels. I did my first truck and reassembled it before I did the second truck, so I’d always have an assembled truck for reference. It might be possible to start out drilling all the holes in the wheel 0.063 at the start, but I didn’t want to take a chance with slop of the gear nub in the wheel. It too might be possible to use just one steel drive pin per wheel.

The straight side of the drive gears beyond the bevel gear teeth are about 0.180" thick. The gears are 0.326 in diameter. I wanted to remove 0.060 from the gear thickness. To reduce the gear thickness by this amount I found a piece of 0.110 thick plywood. Onto the plywood I glued a piece of 0.010 styrene. I then drilled several 0.323 (drill P) size holes in the plywood and styrene near its edge. I chucked a rotary burr in the Dremel tool and carefully enlarged the 0.323 diameter hole in the plywood until the gear just slid into it. Using the dial calipers I checked to make sure that not more than 0.060 of the gear protruded from the plywood. This is a cut and try procedure. It took me a few holes to get the gear to project the right amount. You can use anything for a spacer as long as not more than the 0.060 of the gear projects beyond it.

Use a cutoff wheel in a Dremel to remove the projecting portion of the gear. I’d suggest you measure the total thickness of the gear before you start, and then rub the gear the cut gear on a file to get the last few thousandths removed. Using this method my gears turned out great! Once I’d cut the gears to their final thickness, I drilled the pin drive holes to a uniform depth and made eight new matching drive pins and installed the finished gears on the drive wheels.

Once the geared side of the trucks are done its time to remove 0.040 from the other side of the trucks. The cast axle bosses on the trucks project about 0.070. I found that a #6 brass washer was almost exactly 0.030 thick. I enlarged the hole in a washer just enough for it to slide over the truck axle boss, I then used a Dremel sanding drum to grind the boss down to the washer. I’d measure the width of the trucks before I started grinding. and I finished removing the last couple of thousandths from the bosses with a file to get an exact 0.040 of stock removal. It is also necessary to remove about 0.040 from the ends of the axles which stick into the bosses. I also did also this with a sanding drum in a Dremel tool and used a caliper to measure stock removal. Lastly, I used a Dremel cutoff wheel to smooth and radius the axle ends.

I assembled the wheelsets to gauge using an NMRA standards gauge and then assembled the trucks with the new wheelsets. I then checked to make sure that they rolled freely. One of mine didn’t at first, so I disassembled it and filed just a bit more off of the spoked side axle bosses until it did roll freely. Somebody at Bachmann is an On3er because the brake beams already put the brake shoes at the correct spacing for On3. While I had my rear truck apart I also added a sound cam to one of the axles and mounted the wiper. I was fortunate that my Shay ran great as received. After conversion to 36 inch gauge it runs equally well.

Image of converted shay truck with sound cam

Don Smith