I bought one many years ago to install in one of my Big Haulers.
I converted the Big Hauler to battery power and a 2.4ghz Train Engineer radio controls. I was able to figure out how to connect the bell and whistle and made a 5 volt dc to dc converter to power the sound card from the same 14 volt batteries that powered the rest of the locomotive. The problem I ran into was when I hooked up the wires to the motor that would sense the voltage, and therefor increase or decrease the chuff rate, was the sound card would just take off to maximum chuffs no matter how slow or how fast i set the throttle. I then realized that the Train Engineer was Pulse Width Modulation. This type of speed controller send pulses of full battery power to the motor to control it's speed. The more pulses per second, the faster the the motor spins. The fewer pulses, the slower. The sound card was just sensing the full voltage. I did use it for a while with the Bachmann chuff card, just used the bell and whistle and not the chuff.
I suppose one could put a filter, PWM to analog converter board, between the motor and sound card to smooth-out the signal.
What I did instead was to pay slightly more then twice as much, $79, and purchased a MyLocoSound sound card. Didn't have to figure anything out, it's adjustable and it runs off the same battery voltage as the rest of the locomotive.
If you're running dc track power and want to trigger the sounds with magnets then for just basic sounds, better then no sounds at all, then I'd go for it.
Hope this helps.
Adam