That's a pretty interesting locomotive. The ET44AC was GE's way of showcasing their emission-reduction technology on both mainline and test tracks. The only railroads I know of that doesn't have a Tier-4 locomotive is Candian Pacific. Rebuilds don't count towards Tier-4 emissions standards, or do they?

-Zach (a.k.a. "LittleFalls_Railfan")