When word came round last August that the hobby shop had just gotten in a large N scale collection, I went to see it, thinking I could use another passenger locomotive, or perhaps some more Kato passenger cars. You know, something with lights, that would look good in a darkened driveway. What I found checked both boxes: a Kato RDC (Rail Diesel Car). The prototype was manufactured by Budd, the same company that made those lovely stainless-steel streamliners, and served as a one-car passenger train for railroads working to economize their passenger service. Never mind that none of the railroads I model had RDCs, this one was in Budd demonstrator livery, so it’s easy enough to rationalize its presence in my railroading activities.

Frank from the shop and I took it out of its box and gave it a quick spin on the test track, and it ran as well as I would expect a Kato product to. “Is there a decoder available to fit it?” I asked. Frank looked it up, and sure enough, Digitrax had one specifically for it.

“It’s a tricky one,” he said. He named a mutual friend of ours, one with a sizeable collection of DCC-equipped Kato passenger sets. “He couldn’t install this,” he said, giving me a wink, “but you could.” He sure knows how to close a sale, that man. I purchased the car, and ordered the decoder.

As soon as decoder arrived, I began disassembling the RDC for the install. That’s the first challenge: just getting the shell off. It’s a very tight fit, and it took a combination of some cardstock slipped inside the car sides, some tugging on the steps at the long end, and the judicious use of untrimmed fingernails to get the job done. The rest of the disassembly calls for some patience, but isn’t too challenging to somebody familiar with the Kato Way of Making Things Fit Together.

The decoder itself has not one, not two, but three light boards dangling off it: a board for headlights and markers for each end, and an interior light. There’s also a plastic Kato clip for the last board. (A diffuser bar was not included, though. I had to rob one from a coach.) There’s a whole process for threading the wiring through the interior insert, notching out the exterior-light clips, and making sure that all the contact strips are hitting their respective copper pads. I followed instructions, and when everything was in place, I put the assembled chassis on the rails for a test.

The motor responded, and all the lights lit up. Fantastic—now let’s see about tidying things up.

In an effort to keep the interior from looking too much like a rat’s nest, I shortened and re-soldered the wires, then lightly tacked them down the center of the interior with dabs of white glue. This takes a while; on porous surfaces, white glue grabs within a few minutes, but for plastics, it needs to be clamped or weighed down for at least 90 minutes. I did it in steps, giving everything time to dry in between. Once the glue was thoroughly dry, I put it back on the rails, and spent a little time massaging the CVs with JMRI. For whatever reason, the headlights and markers are backwards on the Digitrax DN143K2 decoder. Everyone with an installation blog or video mentions this. Remapping the white and yellow functions fixes the problem.

Initially, I didn’t glue in the light board bracket, and when I reassembled the car, the LED wasn’t aligned properly with the diffuser bar. I pulled the shell off, glued in the bracket and the board, and added a styrene support prop for good measure. I put it on the rails once more for a final check, and…

You’ve gotta be kidding me. One of the headlights was out. The other headlight, and both red marker LEDs, were working fine. I checked the wires. I fiddled with the contact strips. Nothing helped.

Oh, wait. It’s working again.

Never mind. It’s out. It blinked on, then off for good, as I sat there and watched it from two feet away. The other lights didn’t so much as flicker.

This was where the guilt started to set in. Was I careless when I reattached the wires? Did I bump something too hard? Did the box fan in the living-room window cause a power surge? Did I scuff my feet across the carpet? It’s a bad frame of mind for troubleshooting, so I backed away from the workbench and called it a night.

During my time away, I considered the situation, and concluded that the most likely cause was a bad LED. The two headlight LEDs with this decoder aren’t those lovely warm-white ones that Digitrax has been putting in their decoders for years now. They’re amber. Remember amber headlights? Do they bring back pleasant memories of early-aughts model railroading for you? They bridged the awkward gap between grain-of-wheat bulbs and the beautiful warm-white LEDs we have nowadays. I have to believe that this decoder has been sitting in Digitrax’s warehouse for a while.

At this point, any sensible person would simply pull the decoder back out, and send it in for warranty. Sure, that would spare me the fretting of diagnosis and repair, but would probably mean starting the install over from scratch, and I’d still have a shitty amber headlight.

The next day, I unsoldered the wires to the light board, pulled it out, and reached for the CR2032 coin battery I keep on the bench for LED testing. As I poked it into the underside of the board, I got the red LED to blink, but not the amber one. It’s dead, then. Well, good riddance. I had a spare white LED (the too-short one from the E-7 install) handy, and ready to go. Unsoldering the old LED, cleaning up the through holes in the board, and soldering in the new one was a delicate task, but not time-consuming. I reconnected the board, and set it back on the test track with bated breath. And…

The new LED, and everything else, worked as advertised. Now one end has a better-than-original headlight. I was just sensible enough to refrain from doing the other one. After further checking to make sure the chassis absolutely, positively needed no further work, I snapped the shell on one last time.

The RDC was finished just in time to participate in the last driveway session of the 2021 season, where it chased the California Zephyr during bratwurst and hard cider, and looked good doing it. Several weeks after that, train shows started becoming a thing again, and the RDC proved its worth there, too. It made an ideal test vehicle for a freshly-assembled show layout, and an easy way to have something running at the show’s opening. I suspect it’ll find a permanent home in my show crate, right next to the C-Liners.