OKT 503 train passing through Enid on the former Rock Island mainline. Power is provided by 2300 horsepower GP39-2 locomotives #362, #372 and #370. Built by EMD in April, 1984, these were the last new locomotives ordered by the MKT. Because they were constructed after regular GP39-2 production ended, their carbodies closely resembles the GP49.

After the merger of the MKT into the Union Pacific, in 1988, locomotive #362 became UP #2361. It is now UP#1211. MKT #372 became UP #2371, then WP #2371. It was retired on 25 July 2000 and is now Louisville & Indiana Railroad #2371. MKT #370 became UP #2369, then WP #2369. (The WP reporting marks are used by the Union Pacific to make room for additional locomotives on their roster.)