D&RGW 105

This little locomotive was used on the D&RG from its beginning in 1881 to 1891 when it was sold to the RGS. Since my home layout is the D&RGW after 1924, I modelled this locomotive as if it had been kept in the D&RGW system and upgraded with a new cab featuring a curved roof instead of the peaked version as well as new decals reflecting a later rendition. This was the first RLW locomotive I have assembled, and was built on a used Marklin 8800. It barely ran from the beginning and I suspect it had been run on 12vdc before I aquired it. For years it has been nothing more than a static model. I decided to bring it back to life and this page will outline the re-construction featuring a Digitrax DZ121 decoder and full front and rear lighting. I started the rebuild by disassembling the locomotive and preparing a new chassis for it. This time, I used a newer design 8805 that features 6 wheel electrical pickup and I milled it according to the kit instructions. This is a really simple kit, so I'm only highlighting the DCC installation here. The milled and painted chassis is shown here. The clear electrical insulator was glued to the frame with ACC and the wheels were cleaned and reinstalled. The biggest challenge with converting this locomotive to DCC is where to put the decoder and how to run the wires so that the locomotive can be pulled apart to service it, or change a light bulb or even a decoder if needed. After much deliberation, I decided to hide it in the boiler casting. This required that the majority of the "heft" of the boiler be milled out to house the beefy Digitrax DZ-121. Maybe some weight could be retained by using a Lenz decoder, but I had to use the decoder that I had on hand at the time. The finished super structure will still out weigh the original Marklin shell, so performance shouldn't fall off much. I used a variety of carbide cutters in my Dremel to cut out the boiler. I even cut out a trough to house a couple 560 ohm resistors for the 1.5v micro lights and a channel to bury the wires in. The 'hogged' out shell is on the right and below that on the left is the shell with the decoder positioned inside. Before I could install the decoder into the boiler, I had to run the wires for the light and install the bulb into the oil lamp on the locomotive. I drilled a hole at an angle through the lamp and into the boiler. I was able to drill this hole so that the wires are not visible anywhere on, under, or behind the lamp. The photo on the right shows the drill bit, still in the pin vise, protruding through the lamp and boiler. Once the hole was in place, I enlarged the inside of the oil lamp casting so that the bulb would fit inside leaving the lens flush. I removed the lamp casting from the boiler and positioned the bulb inside and secured it with multiple applications of Testors clear parts cement. Once the cement had dried, I tested the bulb with 1.5v DC to make sure nothing had shorted against the white metal casting. With the light in place, and working as shown below, the next job was to install the resistors and terminate the wires coming out of the decoder. I started by laying out the decoder and trimming some of the wires to length. You can see all of the components in the lower left photo. The resistors will be soldered to the the one side of the lamp leads and also to the light function outputs. The remaining light leads get connected to the common (blue) wire. The outputs to the motor will be soldered to a piece of pc board tie material and this slips into the area where the old round Marklin capacitor once was. Paper insulators isolate the power pickups from the motor brushes and phosphor bronze pickups were formed and slipped into place to privide power to the decoder. The red and black wires will be soldered to these pieces. The whole idea is to have a decoder that 'plugs in', and a loco that can be returned to analog service even if the decoder goes bad and gets removed. The hardest part ,by far, has been  planning this thing out to maximize space followed by milling out the boiler. We still have to solder everything up, make sure nothing is shorted out, and stuff it into the boiler shell, but I think we're on the downhill from here. Since we have both a front and rear light function with this decoder, I drilled out the rear oil lamp from the back, inserted the 1.5v micro bulb, secured it with ACC and filled the lens cavity with the Testors clear parts cement. The leads are routed back under the cab roof, through the cab, and down through a hole drilled into the boiler cavity. Once finished, it'll be hard to detect any wires anywhere in the locomotive and I'll still have a small amount of room to glue in an engineer.

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