This MTH SW-1500 (UP #1108) has a ERR DC Commander but no sound (I just did not try to shoe horn a sound system in it) I added sound into a dummy Kline MP15. The Dummy MP15 has a ERR E8/9 sound unit and coil couplers.
At times I also run the SW-1500 with a dummy Weaver GP-38-2 with ERR GP7/9 sound unit.
Gunrunnerjohn would be your best bet, He has help me and others with ERR problems and if anyone can get TMCC control and sound in a SW-1500 it would be Gunrunnerjohn.