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Serves All the West

A History of Union Pacific Dieselization, 1934-1982, Part 1

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This page was last updated on September 16, 2013.

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Union Pacific's first Streamliner is its most famous early motorized passenger train. The celebrated train of 1934 was numbered M-10000 and was a three-car yellow-and-brown lightweight passenger train, an articulated and streamlined four-car trainset powered by a 600-horsepower oil-distillate internal combustion engine. Although it was intended for demonstration purposes and never meant for revenue service, that train and Chicago, Burlington & Quincy's diesel-powered Pioneer Zephyr—developed within a few months of each other—are generally regarded as the first internal-combustion-powered mainline intercity passenger trains in America.

Diesel-electric switchers had been working in the switching yards of American railroads since 1925, quietly racking up records for efficiency, economy, and availability. Even earlier, Union Pacific and other roads had used gas-electric cars for light branchline passenger service, and one of UP's own officers developed the streamlined gas-electric vehicle design known as the McKeen car, which both UP and other railroads bought and used.

Internal combustion diesel engines first came to UP in the mid-1930s with the successor to M-10000, in the form of the road's second Streamliner, a lightweight articulated passenger train numbered M-10001. Separate diesel passenger locomotives began to appear with the arrival of the road's third Streamliner, M-10002, in 1936. The road tested diesel switchers in 1939, buying its first diesel switchers during the following year.

But mainline passenger and freight traffic remained in the steady hands of dependable, though costly-to-maintain, steam locomotives. In the 1920s and early 1930s on Union Pacific, this meant 2-8-2s, 2-10-2s, 4-12-2s, and articulated engines for freight service, and 4-6-2s and 4-8-2s for passenger trains. Until the arrival of M-10000 and the Zephyr, almost no one, inside or outside the railroad industry, knew for sure whether diesels could withstand the rigors of mainline service, not in passenger service and certainly not in freight service. M-10000, as it turned out, became the first in UP's fleet of passenger trains to which it gave the signature name "Streamliner."

During the late 1930s and early 1940s, Union Pacific management, in both the corporate and mechanical departments, became convinced that diesels could handle the more visible, yet lighter-duty, passenger trains, and they found that colorful, comfortable, fast new passenger trains were popular with the public. But they were equally convinced that only more and larger steam locomotives could meet the road's need for high-speed freight service. This was a reflection of the corporate culture these men had grown up in, from a time before World War I, when a better locomotive simply meant a more modern steam locomotive. The major (steam) locomotive builders embraced this thinking. Diesels were fine, they reasoned, but they would never attain the combined power and speed needed for freight service.

By 1945, UP was happy with the performance of its 175 modern steam locomotives, built in three designs—105 4-6-6-4 Challengers, 25 4-8-8-4 Big Boys, and 45 800-class 4-8-4s, all built since 1936 and among the finest examples of steam power ever built. The Big Boys developed 133,375 pounds starting tractive effort, which translated to approximately 6,300 maximum drawbar horsepower. Except for its high-public-profile Streamliners, Union Pacific came out of World War II as essentially a steam freight railroad. Its last steam engine was built in 1944, and by the end of 1946, the road owned 154 diesels—112 switchers and 42 passenger engines—and not a single freight unit.

To obtain the same high performance from a diesel locomotive as it had from the Big Boy, Union Pacific, along with others in the railroad industry, figured it needed a double-unit locomotive (but preferably a single-unit locomotive), of the same 6,000-horsepower rating. (Many railroads embraced the philosophy of trying to replace steam engines one-for-one with equivalently powered diesels, resulting in many customized, non-standard, diesel-locomotive designs in those days.) Although UP had accumulated plenty of experience with its Streamliners and with much smaller gasoline- and distillate-powered self-propelled motor cars (owning a total of 58 cars), the latter all fell into the 200- to 300-horsepower range, much too small to be considered for freight service.

As the railroad looked proudly to its Big Boys, Challengers, and 800-class Northerns and pondered the future, one thing was quite clear. Every one of its competitors—the other major Western railroads—had already embraced the multiple-unit diesel concept for freight service, while UP had rejected it in favor of trying to find the self-contained diesel equivalent of the Big Boy. The multiple-unit "building-block" system, promoted by the Electro-Motive Corp., later the Electro-Motive Division of General Motors Corp.—employed varying numbers of units, all controlled from a single point, assembled for each run according to need, taking into account train weight, train speed, and a route's operating profile.

Early Internal Combustion Motor Cars

The first internal-combustion rolling stock on UP was a series of self-propelled McKeen passenger cars, powered by small gasoline and distillate-fueled engines. These motor cars were designed by UP's superintendent of motive power and machinery, William McKeen, and were built beginning in 1905 by UP in the railroad's Omaha, Neb., shops. In 1908, UP organized the McKeen Motor Car Co. as a subsidiary to sell McKeen cars to other railroads, and production continued in the Omaha shops. With their distinctive wedge-nosed front ends, these cars were designed and operated as self-contained passenger trains, but by 1909, they were powerful enough to pull a trailer.

Competition for McKeen's mechanical-transmission motor cars came in 1911 when General Electric released its own design for an electric-transmission motor car. McKeen's largest vehicle, a rounded-front 300-horsepower car with a three-axle power truck, was completed in 1916 as a demonstrator for Southern Utah Railroad in Utah's Carbon County coal fields (it was delivered on January 1, 1917). The last McKeen cars were completed in 1917, which was also GE's last year for motor-car production. The production of motor cars ceased with the United States' entry into World War I. By 1920, McKeen's mechanical-transmission car had lost sufficient interest among potential customers that UP bought full control of McKeen and formally stopped production. Union Pacific completed several motor cars for itself during mid-1923, using the remaining McKeen bodies.

A growing interest for electric-transmission motor cars after the war led to the formation of Electro-Motive Corp. in 1922 to again market gas-electric motor cars to America's railroads, taking advantage of better and more powerful engines and better electrical control. In 1927, UP began buying Electro-Motive motor cars, receiving 15 cars during 1927 and 1928. Also in 1928, UP acquired two motor cars from Brill, and another two came from Brill in 1930. Several of the mechanical McKeen cars were converted to gas-electrics during the 1920s, and the last mechanical McKeen cars were retired in 1942. Electric-transmission motor cars with both gasoline engines and distillate engines remained in service on UP throughout the 1940s and 1950s, with the last one being retired in 1961.

Between 1920 and 1932, the number of passenger-miles for America's railroads had dropped by two-thirds, inversely matching the tripling of automobile registrations during the same period. The public wanted faster schedules and more comfort. To furnish faster schedules, Union Pacific needed either lighter trains or more powerful locomotives. UP chose to pursue a lighter train, based on its experience with self-propelled motor cars, with their electric transmissions and increasingly powerful distillate engines during the late 1920s. Lighter trains would also spring from developments in lightweight metals during the post-World War I years, and from aerodynamic designs for rail equipment (specifically, Pullman's Railplane of March 1933). More comfort, especially for business and upscale pleasure travelers, would come with new, more modern designs. These developments led Union Pacific in 1933 to ask for the development of the lightweight, articulated passenger train, which became known as The Streamliner. Union Pacific saw The Streamliner as the answer to what the traveling public wanted, and the first Streamliner was M-10000.


Union Pacific's first internal-combustion locomotive was actually the power car of an articulated passenger train. M-10000 was built as the first streamlined passenger train in North America, and was equipped with a 600-horsepower Winton distillate engine, very similar to the engine used two years before in Santa Fe's M-190 articulated motor car. Union Pacific's M-10000 train featured an all-aluminum, wind-tunnel-tested tubular carbody design that marked the beginning of the streamlined era on America's railroads. Concurrent streamlining efforts included Chicago, Burlington & Quincy Railroad's number 9900, the Pioneer Zephyr, completed just two months after M-10000, as the first diesel-powered streamlined passenger train in North America. Pennsylvania Railroad's experimental streamlined pair of electric locomotives, GG1-class 2-C+C-2 unit 4899 and R1-class 2-D-2 unit 4800 (they later traded road numbers as the GG1 design entered mass production) was completed in August 1934, six months after UP M-10000.

UP formally placed its order with Pullman in May 1933, using the proven Winton Engine Co. distillate engine. Three weeks later, in mid-June, Burlington placed the order for its streamlined train, with Winton's new 201-A diesel engine, of which only two small prototypes, and no production versions, had been completed. Both streamlined trains were originally intended to be diesel-powered, but Pullman finished the all-aluminum UP train first, and the new Winton diesel was not yet ready, so UP settled instead on the earlier Winton 191-A distillate engine. Union Pacific's 600-horsepower, three-car, articulated train was ordered from the Pullman Car Co. on May 24, 1933, and was under development and construction between that date and its completion date more than eight months later, in February 1934. (In 1934, the Pullman Car & Manufacturing Co. combined with the Standard Car Co., becoming the Pullman-Standard Car Manufacturing Co., commonly known as Pullman-Standard.)

M-10000 was constructed as an engineering development vehicle to demonstrate the practicality of long-distance, lightweight passenger trains. Early in 1933, Union Pacific set aside $200,000 for the construction and operation of such a train to gather engineering and operating data that could be used in the design and construction of larger trains for revenue service. Unlike CB&Q, which built its Pioneer Zephyr with a particular service and route already planned, Union Pacific had Pullman build the M-10000 as an experimental demonstrator with no market in mind. With seating for only 116 people—about 1-1/2 times that of a single heavyweight coach of the day—its capacity was extremely limited. To recover some of the costs of its development, UP eventually assigned the train to the 187-mile Kansas City, Mo.-to-Salina, Kan., portion of its Kansas City-Denver route after it proved the success of the lightweight train concept.

The train was delivered to Union Pacific on February 12, 1934, and set out on a nationwide tour until late 1934, including a two-month display at the Century of Progress International Exposition in Chicago. The train returned from its national tour and entered revenue service on January 31, 1935 operating as The Streamliner. The name was changed to City of Salina on March 13, 1935. During 1937 and 1938, it left Salina, in central Kansas, at 7 a.m., heading east, and reached Kansas City at 10:30 a.m. Half an hour later, it was ready to head west again, running as far as Topeka, 68 miles, in just 68 minutes. Turning again, it left Topeka at 12:30, getting back to Kansas City at 1:38—another mile-a-minute average speed. Then it left Kansas City at 4 p.m. (5 p.m. in 1938) and tied up at Salina at 7:30 p.m. (8:30 p.m. in 1938). On the 187-mile Salina-Kansas City run, its elapsed travel time was 3-1/2 hours, with 10 intermediate stops. This was 70 to 75 minutes faster than the best steam-powered express on the route, the heavyweight Pacific Limited, which made fewer stops.

M-10000 was removed from service on December 16, 1941, after six years and 900,000 miles of revenue service, and was sold for scrap to Aaron Ferer Co. in Omaha, Neb., on February 13, 1942.

EMD later assigned model numbers to M-10000 and to Burlington's Pioneer Zephyr, using the model AA to denote, "Passenger A unit with baggage compartment. Noted diesel locomotive historian John Kirkland has referred to these power units as "baggage-car locomotives."


Following M-10000 came the M-10001. Actually, two trains were numbered as M-10001. The first M-10001 was a 900-horsepower, six-car fully articulated train, and the first Pullman-sleeper-equipped streamlined passenger train in North America, and Union Pacific's first diesel-powered train. The power car was built by Pullman-Standard (as part of the entire train) and powered using a Winton diesel engine, a General Electric generator, and four General Electric traction motors. The larger M-10001 was ordered from the Pullman Car & Manufacturing Co. on June 30, 1933, one month after M-10000, and just two weeks after Burlington's 9900 was ordered from Budd. M-10001 was under development and construction (including improvements discovered from the operation of M-10000) between its order date and its completion date 15 months later, in September 1934. It was delivered to Union Pacific on October 2, 1934 and toured the United States for display and testing purposes over the next two months. Without its having rolled a single mile in revenue service, UP in December 1934 returned the entire train to Pullman for remodeling and improvement to increase its power and capacity.

The original M-10001 was a 376-foot-long, fully articulated six-car train. It included the 48-foot turret-cab power unit, a Railway Post Office/baggage car, three Pullman sleeping cars, and a round-end coach/buffet car. The remodeled M-10001 was a 455-foot-long, seven-car train. The remodeled train included the 60-foot, three-inch turret-cab power unit (increased by 12 feet to accommodate the larger 1,200-horsepower, 16-cylinder engine), a Railway Post Office/baggage car (increased by eight feet to accommodate a steam generator compartment), a diner/lounge car, three Pullman cars, and a round-end coach/buffet car.

This remodeled M-10001 was equipped with the first production 16-cylinder 1,200-horsepower Winton diesel engine. The new engine replaced a prime mover that itself had represented a previous first—the first installation of Winton's 12-cylinder 900-horsepower diesel engine, both being installed within a seven-month time span.

Pullman delivered the remodeled M-10001 to Union Pacific on May 23, 1935, in a ceremony at the Chicago & North Western Railway's station in Chicago. (C&NW handled the eastern 491-mile leg of UP's transcontinental passenger service between Omaha, Neb., and Chicago.) The train made three test runs between Omaha, Neb., and Portland, Ore., during late May, and was dedicated at the Portland Rose Festival as the first City of Portland on June 5, 1935, entering revenue service the next day when it left Portland on its maiden trip to Chicago.

The second M-10001 remained in service until June 1939, when the train was replaced in City of Portland service by the M-10002 trainset, which had been reassigned from City of Los Angeles service. The 900-horsepower Winton diesel engine and other power equipment from the power car, and the steam generator from the RPO/baggage car, were salvaged by UP in December 1939 and installed in a new carbody (built by Pullman-Standard) that entered City of Denver service as CD-07-C, as additional motive power to support increased schedules and train consists on that train's Chicago-to-Denver route. M-10001 remained stored for two years (without its diesel engine after December 1939), until it was retired and sold for scrap on August 13, 1941.

Electro-Motive company records show an earlier M-10002 and M-10003, to be built after the M-10001. Both were ordered during November 1933 (M-10000 was ordered in May 1933 and M-10001 was ordered in June 1933). The first M-10002 and M-10003 were originally intended to enter service as the initial City of Los Angeles and City of San Francisco, and were also to be designed and built as articulated trainsets similar to M-10000 and M-10001. The two trains were given Pullman-Standard lot number 6433. EMC assigned a common order number, E121, to M-10001, M-10002, and M-10003.

M-10001 was built; M-10002 and M-10003 were not. Using lessons learned during the operation of both M-10000 and M-10001, Union Pacific and Pullman-Standard returned to the design table for additional horsepower to pull the increased number of cars of the proposed new trains. In an effort that would confuse later historians, EMC canceled the remaining units in order number E121 in December 1934 and assigned a new order number (E131) to the newly redesigned M-10002, delivered in April 1936, but Pullman-Standard retained its lot number 6433 for the new M-10002 train. The redesigned M-10003 was later delivered in July 1936 as a spare locomotive set of an entirely different carbody design, being part of the City of Denver order, using Pullman-Standard lot number 6484, and EMC order number E132.

Following the delivery of Union Pacific's remodeled M-10001 in May 1935, EMC produced five boxcab passenger locomotives, of which General Electric completed two units in June 1935 for demonstration purposes. St. Louis Car Co. completed a third in August 1935 as Baltimore & Ohio number 50. Also in August 1935, EMC completed two other very similar units (also under contract by St. Louis Car Co.). These two units were Santa Fe's semi-streamlined 1A and 1B, used on an entirely new train, the heavyweight Super Chief between Chicago and Los Angeles, which made its inaugural run in May 1936. These five locomotives were EMC's first separate passenger locomotives that were capable of directly replacing steam locomotives. They were of heavyweight sheet steel and cast-steel construction, and rode on two two-axle trucks. Each was equipped with twin 900-horsepower 12-cylinder Winton diesel engines, giving them each an 1,800-horsepower rating. Design improvements from these units were incorporated UP's next Streamliner, M-10002.


UP's third Streamliner was M-10002, completed in late April 1936, and was the last of the turret-cab Streamliners. It was also the first stand-alone diesel locomotive on UP. The train entered service as the City of Los Angeles on May 15, 1936, the day after Santa Fe's new heavyweight Super Chief had made its initial run between the same two cities. As with the previous M-10000 and M-10001, Pullman assembled the M-10002, but it was more powerful than they had been, being equipped with a 1,200-horsepower lead unit and a 900-horsepower booster unit, with nine cars. The three-car M-10000 had been powered by a 600-horsepower prime mover and the six-car M-10001 had been powered by a 1,200-horsepower prime mover.

The 900-horsepower, 12-cylinder diesel engine used in the M-10002 booster was the same one that UP had removed from the earlier M-10001 when it was rebuilt to a 1,200-horsepower rating. M-10002 was changed from City of Los Angeles service to City of Portland service in December 1937. It was stored from July 1941 to April 1942, when it was assigned to a Portland-Seattle connection. It was stored again in March 1943, and its cars were removed. The power cars were finally retired in December 1946 and sold to Northrup-Hendy in Sunnyvale, Calif., for use in that company's gas-turbine tests.

M-10003 to M-10006

In May, June, and July 1936, Union Pacific received four identical power sets, numbered as M-10003, M-10004, M-10005, and M-10006. The lead unit of each of these locomotives featured a then-new "automobile-design" elevated cab. Although each unit had two two-axle trucks, the rear power truck of the lead unit shared a span bolster with the lead truck of the booster unit, forming a 2,400-horsepower locomotive from the 1,200-horsepower lead unit and the 1,200-horsepower booster unit. One power set was assigned to the City of San Francisco, two were assigned to the new City of Denver, and the fourth set was used as a spare and was operated on either of the two other routes—from Chicago to Denver, or from Chicago to San Francisco. Earlier, a nearly identical power unit had been completed by Pullman, in March 1936, for Illinois Central as that road's number 121, used on IC's Green Diamond streamlined train between Chicago and St. Louis.

The first of these four locomotives to be completed for UP was M-10004, finished in May 1936, a month after the turret-cab M-10002. While the power units of M-10004 had vertical carbody sides, the train itself retained the tapered-side design of the three earlier Streamliner trains. M-10004 was the first City of San Francisco, and entered revenue service on June 14, 1936. Just 18 months later, in January 1938, M-10004 was replaced by the new E2-powered SF-1, -2, -3. Following a thorough refurbishing by UP's Omaha shops, during which it was renumbered to LA-4, the train in July 1938 entered City of Los Angeles service, replacing M-10002, which in turn replaced M-10001 in City of Portland service. After less than a year, in March 1939, the LA-4 was replaced by new EMC E3s, numbered LA-5 and LA-6. In June 1939, the LA-4 lead unit was rebuilt as a booster unit, renumbered to CD-06-C, and assigned as additional power to the City of Denver trains to support that Streamliner's increased train size and expanded service. The LA-4 booster unit was renumbered to CD-05-C, and also entered City of Denver service. Both units were retired and scrapped with their respective power sets in 1953. (A third booster unit for the City of Denver trains, CD-07-C, was completed using a new carbody and the power equipment from M-10001 in December 1939.)

M-10005 and M-10006 were completed in June 1936 and entered service as the new City of Denver trains on June 18, 1936. After operating for a year, accumulating 765,000 miles and moving more than 129,000 passengers between Chicago and Denver, the two "Denver twins" were renumbered to CD-5 and CD-6 in June 1937.

Completed as a spare locomotive set in July 1936, the fourth of these new power sets, M-10003, was intended to protect the motive power needs of both the City of Los Angeles and the City of San Francisco. In June 1937, it was assigned to the City of Denver and renumbered to CD-07. It remained in City of Denver service for 16 years until it was retired in March 1953. It was scrapped by UP at Omaha in mid-1953.

The three City of Denver power sets, CD-05, CD-06, and CD-07 (the former M-10005, M-10006, and M-10003) remained in that service until the City of Denver trains were re-equipped with modern lightweight equipment from the general equipment pool and E8 locomotives in 1953. All three trains and their distinctive locomotives were scrapped by UP at Omaha during the summer of 1953.


Electro-Motive continued to refine its design for a stand-alone passenger locomotive, based on what it had learned with the five 1,800-horsepower B-B (two two-axle trucks, with all axles powered) boxcab units it built for Santa Fe and B&O, and the two demonstrators, all completed between the delivery of M-10001 in May 1935 and the delivery of M-10002 in May 1936. One of the lessons was that the two-axle trucks did not operate well at high speeds, especially when entering curved trackage. Another major lesson was that these high-speed locomotives needed to be streamlined, similar to the M-10003 to M-10006 power sets delivered to UP in May to July 1936.

EMC's answer to these two problems was the model EA locomotive, introduced in May 1937, with six cab units and six booster units being supplied to B&O, and the E1 locomotive introduced in June 1937. (The model designation "E" stemmed from the original powering at Eighteen-hundred horsepower.) Eight E1As and three E1Bs were delivered to Santa Fe. These two designs were streamlined, and both were equipped with EMC's new three-axle, A1A passenger truck (two powered outboard axles, with the center one unpowered). The truck was designed by Martin Blomberg, who, as an employee of Pullman in 1934, had participated in the patent for the streamlined design of UP's M-10000. By 1937, Blomberg had moved to Electro-Motive. He was also involved during early 1938 in solving the B-B truck tracking problem on Santa Fe's two earlier boxcab units, 1A and 1B, by adding an unpowered axle ahead of the two powered axles. Also in 1938, he designed the leaf-spring, swing hanger-equipped, arch-sideframe two-axle truck that was first applied to EMC's FT freight locomotive.

In October 1937, following the construction of the first EAs for B&O and the first E1s for Santa Fe, EMC furnished Union Pacific with two A-B-B sets of E2 locomotives for its newly expanded, 14-car City of San Francisco and City of Los Angeles trains. As with the EAs, built only for B&O, and the E1s, built only for Santa Fe, these E2 locomotives were built only for Union Pacific. Although they were mechanically similar to the EAs and the E1s (with twin 900-horsepower diesel engines and A1A trucks), the E2s featured a much different exterior design. The EAs and E1s shared recessed headlights and smooth sloped noses, but the E2s boasted bulbous noses with prominent headlight casings, and much automobile-like chrome trim work.

The City of San Francisco A-B-B set of EMC E2s, initially numbered as SF-1, SF-2, and SF-3, were owned jointly by Union Pacific, Southern Pacific, and Chicago & North Western. The comparable City of Los Angeles set, numbered as LA-1, LA-2, and LA-3, was owned jointly by UP and C&NW. This shared ownership reflected the shared operation of these two trains over each road's route: for the City of Los Angeles, from Chicago to Omaha, Neb., via C&NW, and from Omaha to Los Angeles, via UP; and for the City of San Francisco, from Chicago to Omaha, via C&NW; from Omaha to Ogden, Utah, via UP; then from Ogden to Oakland, Calif. (San Francisco), via SP. Shared ownership was seen as the best way to control equipment usage and the costs of operation and maintenance of equipment dedicated to the Streamliner trains. The outward evidence of joint ownership was reflected in the separate emblems attached to these E2 locomotives, and to the earlier City of Denver units.

The EMC E2 A units remained in their respective assignments from their construction in 1937 until the joint ownership agreements were terminated in 1948. The former SF-1 (renumbered to 901A, then 983J) was sold to SP and became that road's number 6011A. The former LA-1 (renumbered to 921A, then 984J) was sold to C&NW and became its number 5003A. The four E2 B units remained in their respective assignments until they were retired and traded to EMD on new E8s in 1953.

These two new E2 5,400-horsepower locomotives would soon prove that diesel locomotive technology could now compete with steam locomotives on the railroad's fastest and heaviest passenger trains. Six months before the delivery of the E2s, advocates for steam locomotives on UP countered the growing acceptance of diesel Streamliner trains in April 1937 with two streamlined steam locomotives, 4-8-2 Mountain 7002 and 4-6-2 Pacific 2906. These two locomotives were first used in July 1937 to power the new all-Pullman Trains 48-49, The Forty-Niner, between Omaha, Neb., and Ogden, Utah, where the train was handed off to Southern Pacific to continue its journey to Oakland, Calif.

GE Steam Turbines

For two one-month periods in 1939, UP operated a two-unit, 5,000-horsepower steam turbine-electric locomotive built by General Electric. It was completed in December 1938 and delivered to UP at Omaha, Neb., on April 3, 1939. Union Pacific historians William Kratville and Harold Ranks described the promise of the pair, writing that the steam turbines "were lauded as replacement to steam—successor of diesels."

The concept of steam-turbine locomotives was presented to UP by General Electric in late 1936, and with UP wanting to try alternatives to steam and the new diesel locomotive, the two companies began development efforts. Just six months before, UP had received the four 2,400-horsepower Pullman-built locomotive sets (M-10003 to M-10006) as part of the newly re-equipped City of San Francisco and City of Los Angeles. The road had also just received 15 new 3900-class 4-6-6-4 Challenger steam locomotives, with 25 more to be delivered in 1937. In addition, 20 new 800-class 4-8-4 Northerns were to be delivered during 1937. The road's mechanical and operating departments were anticipating being able to compare the performance of the most recent examples of locomotive technology—steam, diesel, and steam turbine.

Numbered UP 1 and 2, the two steam turbine units each generated 2,500 horsepower, and burned oil to produce the steam for the units' turbines. Built by GE under contract to Union Pacific, they were the first railway turbine locomotives built in North America. They also represented GE's only attempt at steam-powered locomotives. The two locomotives were under construction during most of two years, with a final built date of December 1938, although a photograph dated December 24, 1937, shows them about 95 percent completed. Both units were tested extensively on GE's test track at its Erie (Pa.) plant until final road testing, which took place on New York Central from January through March 1939. (Richard Browngardt, a retired employee of Bailey Meter Company, sent a comment on September 9, 2013, that these two locomotives had condensing turbines using water tube boilers and advanced combustion automatic controls including feedwater for the boilers. These controls were furnished by Bailey Meter Company from Cleveland, Ohio. The loco boilers were furnished by Babcock and Wilcox from Barberton, Ohio.)

The two locomotives worked their way to Council Bluffs, Iowa, over NYC and Chicago & North Western, and as noted, were delivered to UP on April 3, 1939. During April, they operated in several test and publicity trains between Cheyenne and Laramie, Wyo., between Cheyenne and Denver, and from Cheyenne to Salt Lake City and Los Angeles. They were in Los Angeles for the grand opening of the new Los Angeles Union Passenger Terminal. They returned to Omaha and were displayed near that city's downtown on April 27, 28, and 29, 1939, during the world premiere of Cecil B. DeMille's epic film "Union Pacific" on April 28. During the first two weeks of May 1939, they completed a whirlwind movie promotion tour of the eastern states for Paramount Studios, including an exhibition for President Franklin D. Roosevelt. They returned to UP and made several trips as separate units on passenger trains between Omaha and Denver. In early June, they were reunited and used to take the Paramount movie special back to Los Angeles, after which they returned to Omaha.

Despite all of that high-profile activity, the tests had shown that the steam turbine concept was not quite ready for railroad service, due mostly to the units' low reliability and increased maintenance. Several minor failures had occurred, and at least one major road failure, in which a 2800-class Pacific pulled the pair and their train from Colorado into Omaha. Simply put, the two units were unsuccessful during UP's tests in long-haul service and never entered regular revenue service.

The locomotives were returned to General Electric on June 17, 1939, via Chicago. Representatives from both UP and GE continued to work at improving the units' reliability, with cold-weather tests taking place on New York Central. A February 1941 report by a UP staff engineer was positive in its contents, but by the end of 1941, it was obvious to UP that the design was not what it wanted. On December 18, 1941, UP President William Jeffers notified GE that the railroad had no further interest in the project. After UP pulled out of the project, the units were repainted dark gray and renumbered to GE 1 and 2. During 1943, they were leased to Great Northern Railway for nearly a year for wartime short-haul freight service in Washington, performing without major failure. By late 1943, they were returned to GE and retired.

In a letter to the editor in the February 1970 issue of Railroad magazine, an old General Electric locomotive man, Forman H. Craton of Erie, Pennsylvania wrote:

On May 10, 1943, when I was working on industrial locomotive sales out of Erie, I rode the steam turbine-electric which had been delivered to the Union Pacific in 1938, between Spokane and Wenatchee on the Great Northern. Here is an excerpt from the diary I kept on that trip:

"When we got to the station, we found the steam-electric already there and about to back in on No. 27, a six-car mail train westbound. Floyd Gowans (GE) and Mosher of Babcock & Wilcox were on her. It was very informal; I just got aboard—no pass, no ticket, no release, no nothing—but everyone assured me it was OK. They have christened the locomotive 'The Jeep,' and the GE men with her were known as technical sergeants.

"We pulled out at 7:18 p.m for Wenatchee, 178 miles away. We climbed the long hill west of Spokane like it wasn't there at all. Then we more or less drifted most of the way from there on, occasionally using the rheostatic brake, which the engineers love. The speed fooled the fireman; he consistenly understimated it by 10 to 15 mph.

"Soon it was dark. Great Northern's signal system gave me the jitters a few times. If the green blinked at you, it meant you were approaching a restrictive signal. We got several blinks. Sailing along a single-track crooked line at 70 to 75 mph in the dark kind of made me uneasy, as the enginner usually made no move to slacken speed. On one occasion, we got a blink and then a yellow; but he kept going plenty fast until the red eye actually appeared and it didn't look very far away either. However, he pulled her down very nicely before we got there.

"The trip was made alternately in full moonlight and then sharp squalls. As we approached the Columbia River, we got into some rugged country, running through deep cuts, tunnels and sharp curves until we finally swung around onto the river. During the trip, the fireman regaled me with numerous rattlesnake stories until I doubt if I would have dared put a foot on the ground anywhere except in a station. We arrived in Wenatchee on time shortly after eleven.

"As I had ridden this loco for the first time, out here on the rather God-forsaken job, I felt a great desire to see us make something of this thing. Here was the loco that F. D. Roosevelt came out to see once—now it is out here forgotten by all but the faithful few who have lived with it for six years now, damned discouraging years at that! Maybe tonight the steam-electric won someone else to its cause.

"Mosher, too, has lived with this job since the beinning and is just full of it. He poured out his optimism about our ability to produce an infinitely better loco if we were to make another. The skeptic almost had me sold on it. Maybe one day we shall cash in on this costly experience—who knows?"

My feeling about this locomotive had been that, among other problems, it was so enormously complex that there was difficulty keeping everything functioning properly at the same time. It was interesting, therefore, that when I congratulated Mosher on a perfect trip that night, he told me there had been a couple of minor failures, which he had been able to correct so quickly that nobody was aware of them.

Early 1940s Motive Power Numbering

For passenger locomotives purchased in 1940 and after, and intended for UP's exclusive use on its non-jointly-owned Streamliner passenger trains, UP devised a unique numbering system used to identify the "Motor" sets of locomotive units, in much the same way that the early motor cars and the early Streamliners carried an M- prefix to their road numbers. Thus, the six new, solely-UP-owned E6 units delivered in August 1940 were numbered as the seventh (7-M), eighth (8-M), and ninth (9-M) passenger train motor sets. E3A LA-5 and E3B LA-6, delivered in March 1939, became the fifth (5-M) motor set in February 1941.

As conjecture, the first and second motor sets (1-M and 2-M) would likely have been the City of Los Angeles and the City of San Francisco three-unit, 5,400-horsepower locomotives SF-1, -2, and -3, and LA-1, -2, and -3. The third and fourth, and sixth, motor sets (3-M, 4-M, and 6-M) might have been assigned to the three City of Denver three-unit, 3,600-horsepower locomotives. No documentation has been found that assigns specific motor-set numbers to any of these locomotives, however, their quantities match the apparent general numbering scheme.

On the E3 A and B set and the six E6As that did receive motor-set numbers, the first and second part (unit) of each set was designated with either a -1 or a -2, as in 5-M-1, 5-M-2, 7-M-1, 7-M-2, 8-M-1, 8-M-2, and 9-M-1 and 9-M-2. The A and B suffixes for the A-units and the B-units were added in much smaller lettering on the units themselves to show the differences in the type of unit, although the only B-unit involved was E3B 5-M-2B, the former LA-6. The two E7As (959A and 960A) and three E7Bs (961B, 962B, and 963B) delivered in August 1946 were originally ordered in the motor-set number series, as the tenth (10-M-1A and 10-M-2A) motor set and as additional units for the seventh (7-M-3B), eighth (8-M-3B), and ninth (9-M-3B) motor sets. The very confusing motor-set numbering scheme was changed at the time of delivery of these five E7s in August 1946, and they were delivered in the then-new 900 series assigned to UP's passenger locomotives.

Unfortunately, research has not turned up the reasoning behind the railroad's decision to number its Fairbanks-Morse Erie-built freight locomotive set, delivered in 1945, as 50-M-1A, 50-M-2A, and 50-M-3B. Possibly, the "50-" number series was chosen to allow plenty or room for expansion in the passenger series, since the Erie-built locomotives were purchased as a combination freight and passenger locomotive, only later to be assigned solely to passenger service. They were changed to passenger service about six months after delivery, after having proved themselves unsuitable for freight service.

Early E Units on Union Pacific

Union Pacific's two E3 units (a single cab unit and a single booster unit) were the first production units of that new model, completed in March 1939, six months after the E3 demonstrator was completed in September 1938. The two units were delivered in UP's then-current scheme of Armour Yellow and Leaf Brown (which was later replaced by the now-standard Harbor Mist Gray). Their numbers were LA-5 and LA-6, reflecting their assignment to UP's City of Los Angeles streamliner train. When the streamlined City of San Francisco was wrecked at Harney, Nev., in August 1939, the two E3s were re-assigned to the temporary replacement train, along with the equipment from the original City of San Francisco (displaced in 1937), and operated on that route until the original E2-powered train was returned to service. At that time, the two E3s were placed into UP's general passenger power pool and used as needed on any of road's passenger trains. In February 1941, with the deliverey of new E6s for the new City of Los Angeles train, the two E3s were renumbered to 5-M-1A and 5-M-2B, matching the new number series for non-Streamliner trains.

In August 1940, 18 months after UP received its two E3 locomotives, and as the road continued to convert its passenger trains from steam power to the new diesel power, it received six E6s. These new units were numbered in the new non-Streamliner number series of 7-M-1, 7-M-2, 8-M-1, 8M-2, 9-M-1, and 9-M-2. All six units were assigned to the road's Eastern District trains, and also served as spare locomotives for the City trains.

Possibly the most notable fact about UP's E6s is that they were the first units delivered with the new Streamliner colors of Armour Yellow and Harbor Mist Gray, a color scheme that has lasted almost 60 years, and which today remains as UP's trademark colors. In 1946, these six units were renumbered to 953A-958A, and in 1948, they were renumbered to 992-997. As UP continued to modernize its passenger power fleet, these six E6s were traded to EMD in 1956 for new E9s.

Six more E6s were delivered in February and March 1941, when the service of both the City of Los Angeles and the City of San Francisco were increased from five departures per month to ten departures, using completely new equipment. Each new train was equipped with 14 new cars, and a set of new E6 locomotives. The previous numbering system was continued, making the new power sets LA-4, LA-5, and LA-6 for the additional City of Los Angeles train, and SF-4, SF-5, and SF-6 for the added City of San Francisco train. These new units also carried the new Streamliner colors of yellow and gray, as did their accompanying new trains.

The general renumbering of UP's passenger motive power in 1946, with the delivery of new E7s, changed the numbers of the two E3s from 5-M-1A and 5-M-2B to 951A and 952B. In 1948 they were renumbered to 991 and 992B. They were retired in 1956 and used as direct trade in units for new E9s 901 and 904B.

The E6s were also renumbered in 1946, from SF-4, SF-5, and SF-6 to 904A, 905B, and 906B, and from LA-4, LA-5, and LA-6 to 924A, 925B, and 926B. All were again renumbered in 1948 to jointly-owned 985J, 985BJ, 985CJ, 987J, 987BJ, and 987CJ. With the end of joint UP/C&NW/SP equipment ownership at the end of 1948, the 985J became C&NW 5004A as part of the final equalization. The remaining five units became 985B, 985C, 987, 987B and 987C. All were traded to EMD in 1956 on new E9s.


The production of EAs, E1s, and E2s by Electro-Motive in 1937 served to further refine the builder's design for stand-alone diesel locomotives. Each of these three models used a pair of 900-horsepower Winton 201A diesel engines and General Electric electrical gear. In 1935, EMC completed a new factory at LaGrange, Ill., near Chicago. Previously, the firm had been located in Cleveland, and had contracted with other builders to assemble its locomotive and motor-car designs. The move to LaGrange allowed EMC to pursue its own diesel engine designs, and designs for its own electrical gear.

By mid-1938, these new engine, generator, and traction-motor designs were ready for production. To make use of these new designs, EMC began design and production of three new models: a 2,700-horsepower freight locomotive, the FT, first produced in November 1939; a 1,000-horsepower switcher model, the NW2, first produced in January 1939; and a 2,000-horsepower passenger locomotive, the E3. The first E3 was EMC's demonstrator, completed in September 1938. A similar model, the E4, was first produced in October 1938, but only for Seaboard Air Line Railroad. The new E3, along with the near-identical E4 and E5 models, and the later E6 model, were all equipped with twin versions of EMC's new 1,000-horsepower Model 567 diesel engine, and the firm's new generators and traction motors. While the E3 demonstrators and the first E4s were built in late 1938, the first production E3s were completed for Union Pacific in March 1939.

Union Pacific received only two E3s. The lead unit was numbered as LA-5 and the booster unit was numbered as LA-6. The units were initially assigned to the City of Los Angeles, as indicated by their road numbers. When the City of San Francisco was wrecked at Harney, Nev., in August 1939, the two E3s were reassigned to the temporary replacement train, along with the equipment from the older M-10004, and operated on that route until the E2-powered train was returned to service. At that time, the E3s were placed into a general pool and used as needed on any of UP's Streamliner passenger trains. In February 1941, they were renumbered to 5-M-1A and 5-M-2B, matching the new number series for non-City trains. In 1946, the two units were renumbered to 951A and 952B, and again in 1948 to 991 and 992B. They were retired in 1956 and used as direct trade-in units for new E9s 901 and 904B.


UP continued to convert its passenger trains from steam to diesel power. In 1940, the road received six of EMC's latest offering, the E6. The E6 was itself a continuation of Electro-Motive's improving passenger locomotive design. It was very similar to the E3, E4, and E5 locomotives produced during 1938-1939; the E4s built solely for Seaboard Air Line (with standing nose doors); and the E5s (with fluted stainless-steel sides) built solely for Chicago, Burlington & Quincy. The six E6As built for UP, numbered as 7-M-1, 7-M-2, 8-M-1, 8-M-2, 9-M-1, and 9-M-2, were assigned as spare locomotives for the City trains, and as the first diesel units in the general passenger pool on the Eastern District, UP's Nebraska and Kansas Divisions. In 1946, these six units were renumbered to 953A-958A, and in 1948, they were renumbered again, to 992-997. As UP continued to modernize its passenger power fleet, these six E6s were traded to EMD in 1956 for new E9s.

In 1941, the service frequencies of the City of Los Angeles and the City of San Francisco each were doubled from five departures per month to 10 departures, using completely new equipment. Each additional train was equipped with 14 new cars, and a set of new A-B-B E6 locomotives from Electro-Motive Division (changed from Electro-Motive Corp. in January 1941). Each set was considered to be a 6,000-horsepower locomotive, made up of a 2,000-horsepower lead unit and two 2,000-horsepower booster units. The previous numbering system was continued, making the new power sets LA-4, LA-5, and LA-6 for the additional City of Los Angeles train, and SF-4, SF-5, and SF-6 for the added City of San Francisco train. These two power sets were possibly most notable as being the first diesel locomotives to wear UP's then-new standard colors of Armour Yellow and Harbor Mist Gray, with the gray replacing the previous Leaf Brown. These new Streamliner colors of yellow and gray were also applied to the new cars in these 1941 trains.

The general renumbering of passenger motive power in 1946 changed the numbers of SF-4, SF-5, and SF-6 to 904A, 905B, and 906B, and LA-4, LA-5, and LA-6 were renumbered to 924A, 925B, and 926B. All were again renumbered in 1948 to jointly-owned 985J, 985BJ, 985CJ, 987J, 987BJ, and 987CJ. With the end of joint UP/C&NW/SP equipment ownership at the end of 1948, the 985J was taken by C&NW and renumbered 5004A as part of the final equalization. The remaining five units became UP 985B, 985C, 987, 987B and 987C. All were traded to EMD in 1956 on new E9s.

Joint-Owned Passenger Locomotives

As noted, the City of Portland, City of Los Angeles, and City of Denver Streamliner trains were operated over UP and Chicago & North Western tracks. The City of San Francisco Streamliner train was operated over UP, C&NW, and Southern Pacific tracks. For the first Streamliner trains (M-10001 and M-10002) the entire consist was wholly owned by Union Pacific and the other roads paid Union Pacific a use fee for each train consist. UP was charged by the other roads for expenses incurred while on their lines, and for use of their facilities, while on their respective trackage. The charges were based on complicated percentages and depreciation formulas, depending on the mileage that each train ran on each respective road.

With the arrival of the Pullman-built City of Denver (CD) sets, and EMC-built E2 City of San Francisco and City of Los Angeles (SF and LA) sets in 1937, and continuing with the E3s in 1939, the E6s in 1941, and the E7s in 1946, the three roads decided to actually share ownership of the equipment, with percentages of ownership based on the proportion of each road's route mileage to the total length of the run. Careful records were kept of all servicing and maintenance costs to facilitate equalization of expenses. The roads jointly owned the motive power on the trains, with fractions made up with spare engines and other components. When Union Pacific renumbered its entire diesel locomotive fleet in early 1948, some officials thought that the variety of locomotives used on passenger trains—some jointly operated and some exclusively UP—would make it difficult to keep accurate records for the purposes of equalization. To identify the joint-owned motive power, a "J" suffix was added to the road numbers.

Within nine months, the railroads realized that the separate accounting was unnecessarily cumbersome. This, along with other problems in the equalization procedures, lead to the cancellation of the joint ownership agreement on December 2, 1948, at which time the actual ownership of the equipment was redistributed according to a formula based on the percentage of mileage operated by each railroad. Chicago & North Western's share was three A units: E2A 984J, E6A 985J, E7A 988J; and two spare diesel engines. Southern Pacific's share was an A unit and two B units: E2A 983J and E7Bs 986BJ and 986CJ. Union Pacific took full ownership of all other remaining motive power in the pool.


Between November 1939 and September 1942, EMD continued to build new E6 units for American railroads (UP received its eight E6 cab units and six E6 booster units in August 1940, and in February and March 1941), with production ending because of World War II. As the war was coming to an end, EMD developed a successor model for the E6, which it named the E7. The two did not differ significantly, except in a shorter nose design, which the E7 (and all later E units) shared with the company's freight units, the FT and the upcoming F2 and F3. The first E7s were completed in February 1945.

Union Pacific's E7s were delivered in August 1946 to support the road's intent to boost Streamliner frequency to daily service. Before this, the City of Portland was running five times per month, and the City of Los Angeles and the City of San Francisco were each running 10 times per month. By tightening schedules and exchanging equipment assignments during 1946, the Portland train was changed to six times per month, and the Los Angeles and San Francisco trains were increased to three times per week (12 times per month).

Daily operation of the all-coach and the all-Pullman City trains between Chicago and Los Angeles-San Francisco-Portland, and UP's Challenger trains to both Los Angeles and San Francisco, were proposed as early as 1940. During mid-1944, with many believing that the end of World War II was near, UP again began to ponder the prospect of daily operation. In November 1944, one of UP's competitors, Great Northern, announced that it would begin running its Chicago-to-Seattle train on a daily schedule. In September 1945, the CB&Q-Denver & Rio Grande Western-Western Pacific combination announced that it intended to initiate a new daily lightweight train between Chicago and San Francisco. UP wanted to stay competitive, which meant acquiring new equipment, so it placed an order for 65 cars in early 1946. Another 15 cars were ordered in May, so that by year's end, the road had available a total of 80 new lightweight cars. In June 1946, daily operation began on the City of St. Louis (a St. Louis-Denver-Los Angeles train operated jointly with the Wabash Railroad between St. Louis and Kansas City, Mo.), and in February, May, and November 1947, daily operations began on the City of Portland, City of Los Angeles, and City of San Francisco, respectively.

The unique numbering system that UP used prior to mid-1946 included letter prefixes for units assigned to the City streamliner trains, such as SF for the City of San Francisco, LA for City of Los Angeles, and the unused CP for the City of Portland. By the time these E7 locomotives were ready to be delivered, UP had changed the numbering system, so that the E7s were the first units delivered wearing 900-series numbers (the Fairbanks-Morse Erie-built units were the first of any UP units to the receive 900-series numbers, in May 1946). E7A 907A and E7Bs 908B and 909B had been ordered as SF-7, SF-8, and SF-9; E7A 927A and E7Bs 928B and 929B had been ordered as LA-7, LA-8, and LA-9; and E7As 930A and 931A had been ordered as CP-1 and CP-2. These four cab units and four booster units all were delivered in August 1946 in their 900-series numbers after the passenger locomotive fleet was renumbered, which also took place in August 1946.

General pool units 959A and 960A had been ordered as 10-M-1A and 10-M-2A, and E7Bs 961B, 962B, and 963B had been ordered as 7-M-3B, 8-M-3B, and 9-M-3B. These two cab units and three booster units were also delivered in August 1946 in their 900-class numbers.

In mid-1947, EMD had completed an E7 demonstrator that operated with a four-car all-dome lightweight passenger train built by Pullman. The train (made up of the first dome cars) known as the "Train of Tomorrow," toured the United States, visiting 86 cities. Afterward, EMD sold the train to UP in March 1950. The E7 locomotive, EMD number 765, became UP 988. The entire train was put into service as a connection between Seattle, Wash., and Portland, Ore., connecting with the City of Portland streamliner between Portland and Chicago.

As noted, UP E7A 988J was sold to C&NW in 1948 when the joint ownership agreement was ended. Likewise, UP E7Bs 986BJ and 986CJ were sold in 1948 to Southern Pacific. UP traded the remaining six E7As and five E7Bs to EMD in 1961-1963 on new E9 units.


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