I thought I would add the photos showing LMS installation in an Athearn SD50.
I followed Bill's method to attach the iPhone speaker, except I had to drill and tap a hole for the mounting screw.
My wiring isn't super pretty, but it all fits with no flywheel rubbing and all functions properly. The LM is adhered to the top of the motor with double stick tape.
I used a Kato motor in place of the stock Athearn as they are much smoother operating. The Athearn hex drive shafts are a perfect fit. Unfortunately it does take a little grinding of the frame for it to fit. I adhered the motor to the frame with some epoxy and fiberglass cloth filler.
Last to do is reinstall the handrails and touch up the paint on the detail parts and apply some weathering.
Dan Risdon