I saw AEX 999997 today. It is an ex-RailAmerica GP38 in Frisco paint. That is the first time I have seen, or heard of, a locomotive with a 6 digit number. I wonder if there is an AEX 999998 or 999999.
This is the registered reporting marks for ‘The Andersons’ - they have a collection of switchers and road engines. IIRC, they are based out of Ohio…
Jim