The first unit from SP's order for 279 GE AC4400CWs leads a Trona, CA to Skyline, UT coal empty at Colton, Utah on July 15, 1995. The GE AC4400CW is similar to the C44-9W but features AC traction motors instead of DC with a separate inverter per motor. A grand total of 2,598 AC4400CW units were built by General Electric for North American railroads between 1993 and 2004. The SP 100 was completed for the Southern Pacific in April 1995 and continues to serve on the Union Pacific renumbered the UP 6149.