Having been set out at Belva a few minutes earlier by the Chicago bound 811 train, SD40-2 #5143 leads the 668 train, out of Quinlan passed milepost 363. Behind #5143 were BN SD40-2 #7043, an unidentified F45, and U36C #8736. The 668 train had originated on the BN as the 073 train.

Until the late 1980's locomotives carried two-way radio transceivers preset to specific operating frequencies. The BN radio operated on 161.1 and 161.16 MHz while the Santa Fe used 160.65 MHz. For that reason, the Amarillo dispatcher directed #5143 be set out for the 668 train to replace BN #7043 as lead engine.