Western Pacific’s 15 GP40-2 units, numbered WP 3545-3559,
which went to UP at merger were also placed into storage at Stockton
in March 1983. As were the other units in storage they also were
moved from Stockton to Oroville, Oroville to Portola, and finally
Portola to Salt Lake City. They did not remain in storage for long
though being sub-leased to the Missouri Pacific in December 1983 for
service in Texas. As with the GP40’s also being sub-leased to the MP
they were removed from storage, prepared for movement and sent to
the Missouri Pacific in January 1984 for service in Texas, being
assigned to Fort Worth for maintenance.
All of the GP40-2’s were repainted into UP yellow and renumbered into the 900-914 series, between February 1984 and November 1988. Some units were lettered Missouri Pacific, some Union Pacific, eventually all being emblazoned with the Union Pacific name.
Six of these units 3545-3550, (UP 900-905), were then converted into road slug control units. In December 1990 and January 1991 these six units were renumbered to UP 3002-3007. The other nine units remained in the 900 series. The conversion to road slug control unit was done by Morrison Knudsen at Boise, Idaho and the units then operated in the Hinkle, Oregon area (as both 900 and 3000 series units) pending completion of all six GP40-2 road slug control units and the three road slugs, UP S301-S303. The road slugs were completed on September 29, 1990 and the three 12-motor slug sets (GP40-2/slug/GP40-2) were placed in local and heavy switching service in April 1991. In the early 2000’s they were renumbered 1535-1540.
The equipment trusts for WP GP40-2s 3545-3559 were paid in full by October 1994 and all 15 units were purchased by UP.
A nine-unit group 3551-3559 (UP 906-914) was assigned UP numbers 2908-2916 in June 1995, with two units (UP 2911 and 2915) being renumbered. Reassigned UP numbers 561-569 in July 1996, only one unit (UP 568) would be renumbered. Renumbering came again in March 1997 to UP series 5315-5323 with one unit (UP 5318) being renumbered. In September 1997 these units would be again assigned new numbers, UP 5361-5369 with only one unit, UP 5368, being renumbered. They would eventually be placed in number series 1461-1469 in December 1999. They subsequently were assigned numbers in the high 9900 series.