I have 2 Life-Like Great Northern SD-7s that are in the process of being converted to DCC sound. There is not that much space inside, even removing the weights over the axles does not really help. So rather than messing around milling and muttering, I decided to try something a lot simpler and definitely easier - swap the chassis for a DCC sound-equipped one. Atlas do an SD-7 with ESU sound, I ordered one today. They did not do one in Great Northern colors, It's a Central of Georgia one. I model the Southern so it will fit in nicely.

Fingers crossed that the Great Northern shell will take the Atlas chassis. Both Life-Like and Atlas follow prototype dimensions, so it should do. I'm not that worried about sound in the Central of Georgia, so I'll be getting an Atlas chassis from a model that will take a PNP decoder, or using the Life-Like one with a DCC decoder. An ESU Lockpilot mini decoder is easy to install if hot-wired. The ESU Loksound decoder used in the Atlas Gold models is excellent - I've been using their sound decoders since 2005.