Add multiple receivers to your existing Rolling Thunder set up so you can simultaneously hear multiple locomotives (and accessories) through your Rolling Thunder system! Since each Rolling Thunder receiver locks onto a single locomotive at any given time if you want to have multiple locomotives sound through your subwoofer at once (while double heading for instance) you’ll need to combine the signals from multiple receivers into a single cable going to the subwoofer. This cable will allow you to do just that. In addition we have some exciting new accessories that utilize the Rolling Thunder system and this cable will allow for use of those accessories. Requires purchase of additional receiver.