Assigned to the Altoona helper pool, NS SD40E #6311 was built originally as NS SD50 #6516. It recently acquired a small graphic addition to the long hood, sporting an "N Scale Enthusiast" logo for the 25th annual N Scale Convention, which was held in Pittsburgh this year (June 21-25).
The EMD SD (special duty) series are a strong and reliable kind of locomotive which still serve America's rails today. They have proved themselves reliable by clocking in several million miles of freight service over several decades.