First off, no DCC System will READ on the Main without additional hardware.
Second These Athearn engines used the older Tsunami decoder and they require a Program Track Booster (PTB-100) to READ on the Program track other wise they will fail on the READ.
There is no ACK involved in a WRITE on MAIN, so your last error indicator makes no sense ( no engine on Main ) as the system does a blind write on the main.
Marc
