If it’s new gargraves out of the box, clean it. I seem to recall it has an oil on it so it doesn’t rust.
Also connect legacy to the same rail as the U post. Gargraves is insulated side to side. The wheels should close the circuit between outer rails but don’t leave it to chance.
If the number boards don’t light up when powered up with legacy connected, the engine is probably kaput.
If you disconnect legacy and just apply transformer power and nothing happens, it’s definitely kaput.
If you just bought it from Ro, call them. They’re easy to deal with on taking care of it.