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I started out by disassembling the Stewart/Bowser truck completely removing all gears. You can if you wish retain the original contact bar for the two correctly spaced axles, and then graft part of our contact bar on if you wish. Otherwise we will continue on. I replaced the main gear that transfers power from the worm gear, as well as the large gear that engages the two axles. The remaining axel to be respaced will be unpowered and "floating" which will allow the truck to track well, and transfer more weight to the driving axles. More advanced modelers may want to play with the gears to power the third axles, but we have noticed no slip in performance of a converted truck vs. an unconverted truck.

Working from the side of the gear box left to right. Remove the original side frame mount on the "left side" as pictured here. with a razor saw, and this piece cannot be used and will be in the way of the respaced axle. Do the same for the other side for the gearbox as well. Take the bottom gearbox cover and remove one set of tangs, and indicated with the pencil, as these will intrude into the new axle. Do not remove the mounting lug, even though we removed one set of the side frame mounts on the gearbox side, we will leave this alone as the "free" lug will keep the axle lateral movement to a minimum on the gearbox.

I measured 20mm from the left edge of the middle axle opening, and drilled a hole a little larger then the axle at this mark. go very slowly with the drill, delrin may flex but it can shatter. You can see the new hole in the picture at the left. Do the same on the other side of the gear box. this new hole is where the third axle will be. Using a file, file the hole to bottom of the gearbox opening it up (if it is not already), now the axle can slip in form the bottom of the gear box, much like the others do.

Re-assemble the gear box, with the gears in place, the gear box should hold itself together for you. Remove any excess gear box that you don't need or sticks out too much from where the original axle was. If you wish you may want to glue a small square of styrene cut to shape to seal the end of the gearbox. Test fit the bottom gearbox cover and trim according to the gear box as well. Don't not place the bottom gearbox cover on yet.

Check the new brass bars over, and ensure they are straight, the solder joints are good, and check the ends of the axles in each hole. If the axles appear to be a little tight, then use a round file to open them up. You should open up the new repositioned axle hole ever so slightly so it can float over rough track and not deter from tractive effort of the other axles. Check the fit of the bar retaining pins in the larger hole in the contact bars, the pin should fit, but not too tight.

Start by positioning all the axles into the gearbox as best you can. Take one brass bar, orient it correctly with the retaining pin hole in the gearbox and slip the axle ends into there respective holes. Place the pin through the brass bar and into the gearbox but not all the way yet. repeat the same procedure for the other side.

Test fit the whole assembly for rolling resistance and flexibility. If anything seems too tight, check the axles holes (if the axles seems tight) or the gearbox pin holes in the brass contact bar (if the axels do not twist slightly) and disassemble the axles and check all holes in the contact bars, for loose materials or burrs, and restart assembly again. The picture to the right shows the right axle up a little higher than the one on the extreme left, that is "twist" comes in real handy on rough track.

Once you have done both trucks, install them into the locomotive frame and hook up the wires from the bars to the wires from the circuit board or decoder, install the worm gear shafts and covers and the bottom gearbox cover. Press the retaining pins in and test run the chassis. If you can, check it on a variety of track and pay close attention to how the axles behave. Once complete we move onto installing the side frames.