Union Pacific Diesel Locomotive Roster

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General Notes

This page was last updated on August 13, 2015.

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What do the parentheses ( ) mean?

Listings with road numbers in parentheses denote that the number has been assigned, but the locomotive has not yet been renumbered.

Builder Dates

Throughout this roster, dates shown in the builder's date column are derived from delivery dates to UP, especially for units delivered to UP since 1990. Actual builder's dates as shown on the units' builder's plate may differ by one or two months. Any variation between builder's dates and delivery dates greater than two months is addressed in an accompanying general note.

During late 2003, and throughout early 2004, railfans discovered that many dates on builder plate "decals" on newer GE locomotives had been modified. The variations have been one month earlier or one month later, and may best be explained by UP and GE updating their warranty agreements, with the build date on the decal likely being updated accordingly. The build dates in this roster will remain unchanged for GE locomotives.

Locomotive Model Designations

Throughout this on-line roster, locomotive model designations follow UP's example, rather than the builder's themselves. UP uses SD90AC instead of EMD's SD90MAC-H (8500-8521) and SD90MAC II (8522-8561) to designate the two different versions of their 6,000-horsepower AC locomotive, and SD9043AC instead of EMD's SD90MAC to designate their 4,300-horsepower AC locomotive.

For the new GE locomotives, UP uses C60AC instead of GE's 6,000-horsepower AC6000CW, and C44/60AC (sometimes C6044AC) instead of AC4400/6000CW for GE's 4,380-horsepower AC locomotive.

Both EMD and GE have furnished Union Pacific with mid-range horsepower locomotives that are designed to be converted to high horsepower locomotives (SD9043AC from EMD and C44/60AC from GE). While the units were indeed designed to be converted, the high cost of making the conversion have made the possibility very unlikely. Several sources at UP have indicated that these 4,300-horsepower locomotives from EMD, and 4,380-horsepower locomotives from GE will remain at their original ratings throughout their operational lives.

For its modern era fleet, UP uses these different model designations to support its interface with the Association of American Railroads national computerized UMLER (Universal Machine Listing Equipment Register) equipment information system. Also, some of UP's internal computer systems (such as the Locomotive Management System, LMS) allow slashes (/) and dashes (-) in their data fields, whereas other systems (such as Locomotive Information System, LIS) don't.

For some of the other locomotives on Union Pacific's modern era roster, the roster listing uses a mix of previous owner designations, current UP designations and designations from the railfan community. Examples include the former SP designations of SD40R and SD45R instead of UP's designations of SD40-2 and SD45-2, and builder and SP designations of GP40P-2 and GP40M-2 instead of UP's GP40-2.

These on-line rosters use railfan designations of SD45T-2 and SD40T-2 for SD45-2 and SD40-2 locomotives built for SP/SSW and D&RGW by EMD with what it called "Cooling System Modification". UP uses SD40-2T to designate the rebuilt former SP SD45T-2Rs, and SD40-2 for the rebuilt former SD39s, SD40s, SD45s and SD45Ms. For this latter group, many in the railfan community have chosen to add the R suffix for these units, denoting a rebuilt version of the previous model; the most common example being SD45R because of the SD45-style radiators on these units. UP, however, considers these to be SD40-2s, regardless of the type of carbody these 3,000-horsepower units had prior to being rebuilt.

Another example is the SD38-2s that UP has rebuilt from former Missouri Pacific SD40-2s. UP considers these 35 units to be SD38-2s, identical to the other 23 factory-built SD38-2s on its roster. Some in the railfan community consider these units to be either an SD40-2R, or an SD40-2d, for downgraded SD40-2, but since they are 2,000 horsepower, this roster uses UP's own designation of SD38-2.

EMD 567 vs. 645 Engines

"What would you call a GP20 that has been reengined with a 567 with 645 liners (they are calling it a 645C but it is really a 567C with 645 power packs) and is now roots blown? This one does not fit into the EMD mold." (Doug Cummings, email to the RR Rosters email discussion group, June 25, 2006)

All of UP's 567-powered units after the late 1970s were similarly equipped. I left UP in 1979, and just before I left, a mechanical supervisor mentioned that Salt Lake, Omaha, and North Platte shops (all of UP's heavy shops at the time) had been instructed a year or so before that all of the old 567-powered units were to receive 645 power packs at their next "Class B", which was where they pulled the head-piston-liner combination (known as a "power pack"), and installed new upper bearings on the main crankshaft. Just as information, a Class C was the complete changeout of the diesel engine due to mileage, and an XC was a changeout due to damage. UP's 567-powered units only had another 6-8 years of service (most were retired in the 1983-1985 timeframe, with the last one, a GP30, being retired in 1989), so I don't know how many units even received a Class B before being retired. They were all "Prioity III" by then, which was retirement if any major component failed, anything beyond what was known as "running repairs", or anything that would take more than 24 hours to fix. (Don Strack, email to the RR Rosters email discussion group, June 25, 2006)