LMX B39-8 8551, the sole motive power on a northbound Expediter headed to Kansas City, MO, shot 2 miles north of Narcissa, OK on the Afton Subdivision, March 1988. This train came out of Tulsa and ran up the Cherokee Sub before heading north at Afton Jct (just a bit east of Afton, OK, where I was visiting my parents at the time). These were "power-by-the-hour" diesels, much like the Oakway SD60s. IIRC, all the LMXs are now off the roster.
I am pleased to have seen some of those units whilst they were still running on BNSF. It must be unusual to see a single one on a train, was it a short train, or is that area quite flat?
The Expediters were short TOFC trains BN ran in the 1980s between certain terminals, and most (if not all) these type trains I saw had just one locomotive. BN wasn't as big a player in the intermodal market as Santa Fe was, preferring to lean more toward the bulk traffic (grain, coal, ore, etc), but the Expediter idea was an attempt by BN to get more into this area of freight traffic. I have no idea how long it lasted, however.
