Well, let me comment on this, based on a space in an auxiliary building at my other place, the Railroad Museum of Penna. It's an insulated lean-to on our pole barn paint shop. It contains a large air compressor and two transformers. The transformers give off enough residual heat that it keeps the entire space (about 8 X 16 feet) above freezing except during the coldest periods.
That said, I wonder if a structure housing the electrical gear at one end, separated from the rest of the space by a wire mesh wall with a locked gate, would do the trick. After all, we're talking about a relatively small space required for ticket sales that will only be used half a dozen times annually, and only once or twice during cold weather. And since it's the electrical building, too, some electric heat should be easily arranged.