Indeed, use 4 digit numbering and follow the road number on the loco. Then simply look at the loco and select it and run it. Less brain power to keep track of things.

Using 0077 would work for you, you’ll need to remember of course that you have added two zeros in front of the number on the loco itself. But before doing that consider what other locos you might buy, and what their number is, so you can be consistent with the number of digits you use. Four will always be ok though.