Good morning Nick. Thanks for taking the time to reply to me. I think that the article I read was written by someone who was trying make DCC more mysterious than it really is. I appreciate the way DCC functions, the necessity for the decoder and so on. If I understand you correctly, what you are saying is that I must ensure that the motor contacts are properly isolated from the metal body and loco chassis which using Romford/Markits wheels is of course live to one side of the AC feed. A bit of insulating tape should take care of that. What I think that will have to do, is to mount the decoder in a totally insulated box either in the loco tender or in the case of my two GER M15 tanks in the bunker which isn’t that difficult as the leads of the 8 pin sockets and decoders I have bought are more than long enough to accommodate this.