I have a new 2023 Model Lionel ZW-L powering my O gauge layout. Track is tinplate Lionel, with 022 and pair of K-line 042 switches. I run the layout in TMCC and conventional mode. I also have a separately powered MTH DCS system powered by a Z-1000 brick connected to one loop of track. When operating in TMCC or conventional mode the DCS system is turn off at its own separate power strip. Recently I noticed that in conventional mode (ie, TMCC off and DCS not powered) the whistle controller would not activate the whistle on my postwar early TMCC locos running in conventional mode. I cleaned my track, checked connections and also decided to disconnect the DCS TIU at the track lock on. When I did this I noticed a spark from the wires as a disconnected them from the track with the power off. I also want to emphasize that the Z-1000 was off and unplugged. Once I did this, the ZW-L whistle controller worked normally.
Is there a capacitor or some other component in the MTH TIU what would interfere with the ZW-L whistle controller? Or, is there a gremlin in my layout?
