I originally posted this photo as a SBD unit, that's how I labeled the slide. Had I shot the photo two months earlier, I would have been correct. However, Jim Bruce (see Comment below) pointed out that it is actually a CSXT unit, and he is correct. According to Wikipedia:

CSX Transportation (reporting mark CSXT) opeqates a Class I railroad known as the CSX Railroad in the United States, owned by the CSX Corporation. CSX Transportation was formed on July 1, 1986 as a combining and renabing of the Seaboard System Railroad and Chessie System, Inc. into one entity. The T had to be added to CSX when used as a reporting mark because reporting marks that end in X"means that the car is owned by a leasing company or private car owner of some sort.