![]() |
Technical Data |
The 75-unit fleet of Union Pacific SW10s had served the railroad well in the time since they first came onto the rails beginning in 1979. The changes brought on by the 1982 merger had caught up with these units, and their limitations were becoming more apparent. The motive power practices of the railroad had changed, and many on the railroad see no place for these unique locomotives. As they come due for major repairs, or as their suffer from wreck damage, the units had been and would continue to be retired. Only the growth in traffic in the last few years had saved the fleet this long.
The 1992 acquisition of 32 second-hand MP15ACs was meant to allow the replacement of all SW10s, but the little units were too badly needed to handle the suddenly increasing switching chores systemwide. During late 1994, the stated intent was that should more MP15ACs become available at a good price, this could spell the real final call for another, and possibly the last, unique-to-UP locomotive design. Changes from the C&NW and SP mergers of 1995 and 1996 have changed the railroad's motive power needs, including an influx of former C&NW and SP SW1500s, sealing the SW10s' fate of retirement as soon as possible.
Only UP 96 (ex-UP 1243) remains in service, as part of the historical collection, assigned to passenger service at Cheyenne.