Most of my decoders are wired in. Yes, it takes some time with the Dremel, but you can be careful to remove only the barest minimum of weight. The TCS split decoders can be a handful, though. Most of mine are wired in using the factory light boards and judicious cutting of traces on the boards. But you need to be crafty.
Good for you, you did the same thing I did for the wires. The factory frames and the ones made by some rich guy with a milling machine have rectangular troughs, but that's no fun with a dremel and it takes out too much weight. I just did, as it appear you did, used a file to bevel the tops of the frames to leave a small V groove. Works like a charm.
I have an SD40 from that time period that I'm going to do an install on soon. I bought digitrax's smallest decoder (DZ126T) and will go with this method... http://n-scale-dcc.blogspot.com/2016/04/tcs-m1-in-kato-sd40.html ... or this method where the bottom of the frame is milled out (more complicated)..... http://n-scale-dcc.blogspot.com/2012/10/zimo-mx621-in-kato-sd40-or-sd45.html ... not sure which I'll use at this point. The first link above will tell you which frame you have and what your options are. I have the earlier frame so will have to mill it in one place or another. Here is a link to doing the install talked about earlier with the light boards... https://tcsdcc.com/index.php/installation/n-scale/1947 ... this decoder install costs more for the decoder but is probably the easiest install. I did find some negative reviews on that decoder but not sure how old they were. Sumner
I started the decoder install on a 90's Kato/Atlas GP35 last night which I think is the same as a Kato/Atlas GP30. This is my first 'wired' decoder install so is going a little slow. I disassembled the loco and ... .... milled out a pocket for the Digitrax DZ126T decoder under the rear light-board. The DZ126T seems to be about the smallest one Digitrax makes. ... I also started milling the top of the frame halves for the decoder wires that will run to the motor and front light board. I'm using a mill since I have one and no I'm not rich. The smallest end mill I have is 3/16" so I ordered a couple smaller ones off Ebay to use for the rest of the wiring routes. I'll post more pictures when they come in and hopefully I can complete this. I'm using the following install as a guide and thankful for finding it... http://mysite.mweb.co.za/residents/grela/katosd40.html Sumner
