Hehe, related topics to the rescue.
28mm - What scale?Rail Modelling scale compatible with 28mm?Couldn't we make this a sticky? I don't know how many times the issue crops up in a year.
And to complicate things further,
- Lead miniatures are not scale models (that is, even internally consistent over body parts and items)
- Railway gauges are not scales.
Anyway, there is S gauge, which converts to 1/64 by one logic. Good luck finding any, though. Company B makes 1/56 stuff which doesn't convert exactly to any gauge code. American O gauge (1/48) may be good enough, especially if your minis are "heroic" (that is, closer to something called 30mm or just otherwise exaggerated).
But ultimately, use what fits. That's the best you can do when the scales are not scientifically accurate in either world.