Union Pacific Diesels On LA&SL

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This page was last updated on November 20, 2024.

By John Thompson

The LA&SL was the first district on UP to be fully dieselized, and it was done with EMD F3s and Alco cab units. UP announced in 1948 that the entire railroad was dieselized west of Green River. Of course, there were still many steam locomotives still in service west of Green River, but they were assigned to local service and to helper service on mainline trains.

In 1950, UP decided to standardize locomotive types by district. The EMD F3s were moved to the Northwest District, and the Alco cab units were moved to the South-Central District. Previously, both types were used where ever they were needed. A 1950 aerial photo of the Ogden roundhouse shows very few steam locomotives, no EMD cab units, but numerous Alco cab units. The "Standard" turbines arrived in early 1952, so were not a factor in operations west of Green River. The GP7s were delivered in 1953 specifically to replace steam on the Eastern District branchlines, as per EMD's promotional statements. But after a couple tests on the LA&SL, UP found them successful in mainline service and much more versatile than the cab units. In late 1953, UP ordered 190 GP7s, but in January 1954, EMD announced the GP9, and converted UP's order to be GP9s.

The GP9s were delivered between January and April 1954, numbered upward from 130 to 244. The order included cabless boosters which were numbered 130B-204B. UP 205-244 were built without dynamic brakes due to their planned assignment to the Eastern District. As the initial order was arriving, UP ordered an additional 50 units, to be numbered 250-299. These were delivered in August and September 1954. The delivery of the GP9s were essentially the end of mainline steam on Union Pacific. The remaining big power was concentrated on the Eastern District, where they shared their mainline duties with turbines and EMD cab units.

If you look at a chronology of motive power purchases on Union Pacific, you can see that UP bought 274 diesels and turbines in 1954, and retired 258 steam locomotives. In 1955 and 1956, the numbers were 65 diesels purchased and 185 steam retired in 1955, and 23 diesels purchased and 191 steam retired in 1956. In 1957, UP received 50 more GP9 cab units and 50 more cabless booster units, and retired 113 steam locomotives. These 100 GP9s, numbered in the 300 series, effectively killed steam on Union Pacific. Of course, as steam ended on UP, railfans took lots and lots of photos of these last days showing UP's big steam on trains in southeastern Wyoming and some showing trains in Nebraska, but UP's use of an obsolete motive power design was finally over. Except for the loss of jobs directly related to the maintenance of steam locomotives, there was a great hurrah all across the railroad. There are a few interviews of old men wringing their hands about how great steam was, but anyone younger than 50 years was glad to see them gone.

There are photos by Stan Kistler showing UP freight F3 sets on Cajon Pass in 1951, and another photo in January 1953 showing a set of freight F3s on a train on Cajon Pass, and another in August 1953 showing a set of freight F3s at Colton. There is also photo evidence of new sets of F7s on Cajon Pass when they were delivered new in 1951. Very soon after 1951, the F7s were reassigned to the Pacific Northwest.

Research has found that motive power usage was seldom an absolute. Instead, regardless of assignment, locomotives were subject to variations due to operational reality. When UP replaced steam power with diesels in the late 1940s and early 1950s, they assigned certain diesel types to the LA&SL (officially known as the South-Central District). The reasons given included making fleet management easier, to ensure multiple-unit compatibility, to assist with maintenance including the training of workers, as well as parts inventory. All of these reasons were ideal and desirable, but the territorial assignments were not critical and were not absolute directives.

Mark Amfahr has written,

When everything worked as planned, with normal operation and normal traffic levels, you'd typically see only the "assigned" power moving over Cajon, just as things are supposed to be. However, the minute something abnormal occurred, things could change in a hurry. As an example, assume that ALCO FA/Bs were assigned to the LA&SL for freight operation south and west of Salt Lake City and that EMD F units were assigned to the former OSL north of Salt Lake City and east of Ogden. Ideally, they would only use those locomotive types in their assigned territories. However, on any given day, some eastbound trains from Los Angeles were delayed for some reason, such as a temporary service disruption from a washout, or a derailment, and Salt Lake City found itself short of ALCO "LA&SL" power as a result. Of course, the traffic bound fro Los Angeles continues to flow into Salt Lake City. So if they need to run the hot DLS and LA Forwarder trains to Los Angeles, but don't have ALCOs to assign because of the service disruption from the west, what would be done. Sitting in the Salt lake service area, or perhaps up at Ogden are two sets of EMD F units from Green River or Pocatello laying over, idling away. Now, those may technically be "Wyoming Division" or "OSL"-assigned units, but that's a case were company officers and Chief Dispatchers would be talking to negotiate for the use of those units to move the hot traffic on the LA&SL.

Assuming they get an okay, the "negotiation" may result in the use of the Wyoming or OSL-assigned power for part of the trip (swapped and sent back north when eastbound ALCOs are met en-route), for a single round-trip to Los Angeles, or maybe even multiple trips such as if the LA&SL territory is dealing with a traffic surge they can't otherwise handle. The LA&SL may get the okay for two sets of Fs for a single trip, or three sets to use for a month, or some other temporary assignment depending on the situation.

Motive power assignments were more like guidelines. Exceptions will always exist. A time period with ALCO freight units assigned to the LA&SL and EMD Fs assigned to Wyoming and OSL territories may mean that you'd see 85 percent ALCO and 15 percent EMD F unit power over Cajon. Not 100 percent.

Using photos as the sole source of information will only result in mixed results. Photographers tended to take photo of special situations and oddities. The proportions would be out of the ordinary, everyday happenings. Locomotive types that weren't common in a given territory got much more attention. The best source of information for the actual mix of motive power at any given location would be operations records, such as timebooks and dispatchers sheets, and station agent records, all of which wouold show trains and assigned locomotives within periods of 24 hours, over multiple days.

Recently reviewed dispatchers sheets from Las Vegas in the 1950-1951 period show the locomotives assigned to each train, revealing the variety passing through Las Vegas at that time. Passenger trains usually used solid sets, or mixed sets of Fairbanks-Morse Erie units, or ALCO PA and PB passenger units, or EMD E units. Freight trains used solid sets of either ALCO FA/Bs or EMD F3s. Locals used either FM H20-44 or ALCO RS-2 types.

The hotter trains (DLS, LA Forwarder, UX/UTX/CN, etc.) appeared to favor the EMD Fs, while the ALCOs were assigned to lower priority locals and drag freights whenever possible. The dispatchers' reports mention specifically assigning locomotives to trains by type, as in "use 4-unit set of EMDs on the Forwarder...," possibly indicating the result of the poor reliability of the ALCOs vs. the EMDs by that time.

The sets of freight power that you see departing eastbound or arriving westbound at Las Vegas would have worked to or from Ogden in most cases. Las Vegas would have been the only place where they may have been swapped one set of locomotives for another.

An educated guess for the period of 1950 is that most locomotive consists were worked between Ogden and Las Vegas, where the sets of power were changed, and another set would then take the train from Las Vegas to Los Angeles.

As a side note, the ALCO FA cab units did not have multiple-unt connections on their front ends. The Las Vegas dispatcher's information indicates that they run them in anything other than four-unit (ABBA) sets. There is one example at Las Vegas that mentions an eastbound train departing with a consist of two three-unit sets of ALCOs (six total), but the sheets note that the train was "doubleheaded", which meant two complete engine crews worked the train. This indicates a limitation of possibly a labor agreement that limited the number of working units in a consist operated by a single engine.

Research also suggests that some of the freight F3s stayed on the LA&SL into 1954, when the new GP9s displaced them, and that the freight F7s were never assigned to the LA&SL in the first place.

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