In 1991 EMD and BN jumped into the AC technology. EMD built 4 SD60MAC's prototype units for the BN to test out and were painted in a modified BN scheme. Tests proved successful and paved the road for the order 786 SD70MAC's that would be delivered to the BN/BNSF between 1994-2000. Here one leads an empty train back to the coal mines. The empty is working direction north on the Brookfield towards Galesburg. Now days these units have been held up at the FRA Test Track in Pueblo, CO.