I didn't want to assume that everything that says "DCC and Sound" always lets you turn the light on and off with DCC also. Well, I did assume this but am making sure The manufacturers and most hobby sites are pretty skimpy when it comes to details on features.
That's also part of the problem. I have no idea. It is a Model Power MDP89441 I can't find any information on it other than it has "DCC/Sound". I saw a video of the train on a track and demonstrating it running and all the sounds, but no other information.
If it is a Model Power with factory DCC and sound then it is most likely an MRC decoder as MRC bought Model Power a couple of years ago..