0 scale, as in Zero scale is what we now call O scale. HO scale stands for "half zero", half the size of zero scale. Guage 1 is of course bigger than zero. Put 1/2 gauge in the middle of 0 and gauge 1 size wise. Sounds about right if you're carrying the thing around in a wooden box. What does it measure between the wheels?
Now see you were talking 1/2" = 1 ft. which would be twice the size of O scale. Gauge 1 is described as 1/32. Gauge is 1.75 "