Which post do you speak of? I know there is a big one that was mine, but it was with a conventional locomotive upgraded with a LokSound decoder.
But I'm had the two locomotives for a bit now and had a chance to play with them. Using the NCE command system I have found that they do not operate as MTH says. Like volume. The manual says you have to push F6 twice to change the volume level, and you can do that 10 times to get the 10 different levels. I push F6 and the volume just increases to max. Push it again to stop unless it got to max already (Which only takes it a second or two to do.). Next push and the volume to lowers until you push the button or the volume cuts out. There is no stepping through the volumes, and it changes so fast it's really hard to get the two locomotives I have to match.
And then the smoke unit comes on when the locomotive starts playing sounds either from F3 or by turning the throttle up after a track power cycle. As long as the track how power, the locomotive remembers the smoke setting, but once I turn it off for the night and come back the next day, the smoke unit is back on. The same for the cab chatter setting. But it remembers the lighting settings between track power cycles.
Other thing is the built-in keep alive is only good for sound, it doesn't keep the motors running. I hit a bad spot of track and the loco comes to a dead stop. Lights and sounds keep going for a while before cutting out, but the motors stop. The spot is small enough that a keep alive for motors would get over it just fine, but these locomotives just stop dead.