I spotted CSX SD40-2's <--8182 & 8274--> with about 25-20 unloaded coal hoppers and then I saw 8200--> running backwards on the other end of the train. Coupled to that engine was about 6 heavily blackened Railbox Boxcars with a Yellow notice on the last boxcar that read: "TEST CAR DO NOT HUMP". about 30 minutes later I was stopped at the same crossing again, and then here came 6 "black" (really yellow, but were so dirty) Railbox Boxcars with 8200 pushing them with about 25-35 empty coal hoppers with 8274 and 8182 pushing. I haven't heard of any track repair on the scanner and ther hasn't been any rain in a week. Yet another Odd Sighting On CSX"S Cowen Sub.