"...was this not a topic cast to us by an individual in the tea room..? " Tea room? You been seeing a posher training outfit?
"It's 110V between the two lines, and 55V between either line and earth. While one line is positive, the other is negative." Being a pedant, positive and negative only applies to DC. With AC, the voltage cycles from pos to neg and the rms votlage on either side of the transformer.