Here's another decoder install. My Atlas GP-7 is Canadian National #1721.
As I said before, my decoder brand of choice is TCS, with their “goof-proof” warranty and their “dithering” function for ulta-low speed crawl. Again, I am using a TCS M3 decoder, which has motor control and 3 functions for things such as lights. I only used two of the functions but the third is there in case I want to put a strobe light on the roof... Which would be insane, but I've done it before. Remind me to post a movie of my N scale SW8 in action. :-)
Atlas GP-7 Decoder Install