The CSX #1717 in the photo is one of a group of CSX ex-SD40-2 locomotives (now 1713-1727) that are now Tier 4 SD23T4s after an upgrade with the installation of a Wabtec/GE inline 6 cylinder diesel engine and the enlarged radiator for Tier 4. The diesel is rated at 2350 HP, whereas a SD40-2 is 3000 HP. It is reported to be the only conversions of EMD locomotives to have a Wabtec/GE prime mover installed. Wabtec calls them ET23DCMs.