I found the problem quite by accident. I put a passenger train with 12 K-Line HeavyWeights on the track, pulled by an MTH Reading T-1 PS2. The engine started up, but I got double responses to whistle commands and loss of control at the far end of the layout. The remote also displayed an out of RF range message. I tested an MTH SD40-2 on a separate 3' section and got 10s, so I knew the SD and TIU were okay. I pulled all the cars on the lay out off, left the GPs on a powered siding where they have been, and put the SD on the track. Close to the TIU, I got 7s. The further away the SD was, the lower the readings. Pulling all the GPs off restored the readings to 10s everywhere. Putting the dummy unit on the track had no effect on the readings. Putting each GP (one at a time) on the track did! I found 2s and 3s at the far end with either unit. Putting both on really killed the DCS signal.
I'm going to check out the links GRJ has above and order about 10 of the chokes. I have numerous TMCC engines I've never tested for this effect.
Chris
LVHR
