Here is an Atlas O dual-motor GP60 DCC installation, which encompasses a Protocraft-modified (3.5 Amp) Soundtraxx Tsunami Sound Decoder PC-827103 - the correct sound for this loco versus stock QSI decoder). The motors are wired in series and the two Protocraft decoder boards are mounted to the die cast metal frame for good heat dissipation (drilled and tapped frame for 2-56 machine screws). I added two Train Control Systems (TCS) KA2 Keep Alive capacitors (block-like things wrapped in black electrical tape) wired in parallel to the decoder bridge rectifier board. The resistors in the photo below the Keep Alive caps are for the stock LED lights (470 Ohm 1/2 watt each). The two Keep Alive caps give this dual-motored locomotive a "power-interrupted" run time of about one engine length when running light engine at speed step 20 out of 128 - lights never flicker and sound never cuts out after about 2-minutes of initial charge time; even on dirty track. Using a Soundtraxx PTB100 programming track booster allows reading and writing values to the decoder with no problems; even with the Keep Alives installed.
Scott K.
Austin, TX