Railworks America

I've just downloaded a route. It's a nice route, but everything's in metric, mileages steam pressures etc. I'm pretty sure you can change it, because I think I've done it before.. The only trouble is I can't remember how I did it. (searched the manual but it tells me nothing, of course). Any help would be appreciated, thanks.

I doubt it all depends on the route.
Instruments in the cab are defined in the loco blueprint and textures;
Pop-up messages are defined in the scenario.

I should have clarified what I'm refering to is the '#5' HUD readouts. Nothing to do with the engines really.. I get imperial readouts in most routes using the same engines.