I got it working. Thanks to @Norton for the help with the voltage conversion. I just need to “install” it now.
Bit of a tight fit with the horizontal motor, the decoder is gonna have to go above the rear drive tower and the speaker in the roof of the shell.
Parts:
Bridge : https://www.amazon.com/gp/aw/d...pop_mob_b_asin_title
Voltage converter: https://www.amazon.com/gp/aw/d...pop_mob_b_asin_title
Blunami 4408 EMD Diesel (885617)
Speaker is a 40x28mm 8ohm 4w from streamlined backshop.