How about an inexpensive (>$13 delivered), simple, good sounding, locomotive sound option for DBTC (see HO size picture)? Just stick it on, add a removable-fake-trap and make it look like an over-sized load, and then put it directly behind the locomotive you want to have sound effects. That’s right; it is battery powered and will play sounds from any iClone. [Open-source iClone App developers, here is your chance to get in on the ground floor.]