I didn’t see mentioned here is that Lionel engines operated at the same time as mth on the same track can reduce the signal. Same with constant voltage lighting (like from cabooses).
Are you running either one on the same track with the mth items? If so, while you are doing your testing you might want to remove them.
Have the tracks been cleaned recently?
I use gar graves, but remember atlas track used in the past needing to be cleaned more frequently.
Mike
