Reply to "ZW-L Quirk"

I'm thinking the meter readings aren't all that precise.  Or the locos aren't predictably reducing their amperage draw proportionally when you increase the volts to 18V. These systems are far from linear.  It's total watts that are presumably tripping the overload circuit, and when you use 16V, your amperage draw is proportionally less rather than proportionally more than at 18V for some reason.  Hence the overload.  There's nothing magical about the meters if they're not reading true peak voltage or amperage, which I'm guessing they are not.  Somehow you're exceeding the overload setting at 18V, but not 16V with these particular locos.  May not be a flaw in the ZW-L, just too much power draw at 18V given the mechanical/electrical properties of the locos and the mechanical load put on them by these cars.