Believe it or not, the Atlas SD60M pictured
below contains a Soundtraxx chip, decoder, and two 5/8th inch
speakers, while maintaining its full power drive mechanism.
Full Side Profile:
Here you can bearly notice
that the DSX chip is located in the fuel tank. You can also
see the sides of the two speakers inbetween the trucks and the fuel
tank. Also the capacitor required is located in the rear of
the loco (left side of photo).
Front Side Profile:
Here you can see more
closely the cut out for the 5/8th inch speaker. This version
also has a spring mechanism to pick up power from the truck sides to
the frame halves.
Rear Side Profile:
You can again see the
cut out for the second speaker and a closer look at how the DSX chip
fits under the more and in the fuel tank area. Wiring goes up
to connect to the speakers and the capacitor.
Here you see a birds
eye view of the bottom of the unit for placement of speakers and DXS
chip. You can also see that the power leads of the sound chip
are connected to the frame directly to the right of the chip.
-Atlas SD60M (or SD60 or SD50)
-Decoder (a few can be chosen)
-Use 1/2 inch speakers for better volume. This will require cutting the shell of the loco.
-Possibly add a third speaker in the cab.
-Hardwire all chips together from truck pick up, to decoders, to motor for better reliability.