For Fuck's Sake, Atlas. "DCC Ready", my ass.
First of all, it's 2025. If your locomotive (which came out this year) doesn't have a DCC plug, it's not DCC Ready. It just isn't. I can almost forgive Kato because I'm fairly certain they've never heard of Next18 and E24 (and even NEM 651) over in Japan, but you guys? I know you know what a Next18 plug looks like, I own your ALP-45PD. And the associated cab car, and why only of the two has ditch lights wired up is… besides the point here, I'm talking about a GP60 now, but also get on that.
Anyway, you market it as DCC ready, and it does have space for a speaker (personally I don't see the point in sound for model railroad locomotives, but apparently that's a me thing). What decoder do I need? You say it's Decoder ready, surely you have some decoder in mind? One of those board replacement thingies from Digitrax or whatever that other one is called, right? What is it?
Oh, of course Atlas won't tell me. Neither will Digitrax, apparently, because nobody told them Atlas makes a GP60. Just great.
Anyway, for the record, if you have an Atlas N scale "Master Line" GP60 locomotive, in my case #40 004 898 (that's Southern Pacific #9776):
To open the locomotive, remove the tank (plastic piece at the bottom, just pull gently), then gently insert a small flathead screwdriver between where the tank was and the underside of the walkway; towards the rear. Twist it; this will start lifting off the body (walkways and all) from the rear. You can mostly just pull it off but be really careful at the front, the fibre optics towards the lower ditch lights will catch and you don't want to rip them off. To reassemble… I don't know, haven't gotten that far, but my gut feeling is to do the same in reverse, making sure to keep the fibre optics out of the way, and then reinsert them in their holes in the body with really thin tweezers. Unscrewing the front coupler first may help with seeing what you're doing.
Inside the locomotive is a PCB that reads 1660-E003, which is 66mm long and 8.3 mm wide. The fibre-optics for the ditch-lights are held by a plastic piece leading to LEDs on the underside of that board (not glued on as I said initially, I just misunderstood things at first). At least my locomotive only has ditch lights in front, not rear, but there are rear ditch light LEDs fitted presumably for other variants.
From the pure dimensions, there are a number of boards that seem like they might fit, e.g. Digitrax DN166I3 (yes, I), ESU "LokPilot 5 micro DCC Direct Atlas Legacy" as well as the associated LokSound, the TCS AMD4 appears to be a bit too short but I'm not sure that'll be a problem, but none of them feature ditch lights. The ESU one would be my favourite, but it doesn't appear to have any directional LEDs at all and it's also not currently available.
So… I dunno. I'm going to have to think about that for a while. Wiring something in manually would be quite a pain, but there's a bit of space especially at the rear end, and I do have some Next18 and E24 connectors and I know how to design my own replacement PCBs for trains…
