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Steam Locomotives of the Union Pacific (UP)[Inhalt]
Union Pacific No. 119
United States | 1868 | 5 produced
The replica at the Golden Spike National Historic Site at Promontory Summit in Utah
The replica at the Golden Spike National Historic Site at Promontory Summit in Utah
Mr Snrub
Zeremonie vom 10. Mai 1869 am Promontory Summit
Zeremonie vom 10. Mai 1869 am Promontory Summit

In 1868 Rogers delivered five 4-4-0 locomotives to the Union Pacific, of which number 119 achieved great fame. When the gap on the First Transcontinental Railroad was closed on May 10, 1869, it was the locomotive that was brought by the Union Pacific, together with its Vice President, Thomas C. Durant, to the Promontory Summit in Utah. It took part in the ceremony there together with the Central Pacific's “Jupiter”, from which a famous photograph exists. In 1979 a replica was built by O'Connor Engineering Laboratories and it still exists today.

General
Built1868
ManufacturerRogers
Axle config4-4-0 (American) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Adhesive weight36,000 lbs
Axle load18,000 lbs
Fuel capacitycoal
Power
Power sourcesteam
Indicated power290 hp (216 kW)
Optimal speed17 mph
Starting effort10,995 lbf
Power Plant
Driver diameter57 in
Boiler pressure120 psi
Expansion typesimple
Cylinderstwo, 16 x 24 in
Boiler
Calculated Values
steam locomotive
passenger
freight
last changed: 05/2023
Union Pacific class 3900 “Challenger”
classes CSA and 4664
United States | 1936 | 105 produced
The last Challenger built, no. 3949
The last Challenger built, no. 3949
collection Rich Driver

In the 1930s, the Union Pacific was looking for a more powerful engine that could haul heavy passenger and freight trains faster over mountain lines like the Wasatch Grade. Although a twelve-coupled locomotive was already in use with the class 9000, the locomotive soon to be called the “Challenger” was designed as an articulated locomotive. While most other articulated locomotives were designed for high tractive effort at low speeds, the Union Pacific now designed these locomotives for speeds in excess of 60 mph or 97 km/h.

The first production batch, like all others, came from the ALCO plant in Schenectady and was designated class CSA-1. With an integrally cast frame and roller bearings on all axles, the targeted speeds could be easily reached. While the front, two-axle bogie ensured sufficient running stability, the trailing, two-axle bogie enabled a large firebox

The following year 25 CSA-2 were built, which were almost identical. One difference, however, was the approximately 10,000 pounds increased adhesive weight. Six of these locomotives were fitted with steam heating in order to be able to pull passenger trains. One difference within the first 40 engines was that some had a Worthington feed water heater and some Sellers exhaust injectors

After realizing that the Challenger could no longer handle the 3,600-ton freight trains on Wasatch Grade alone, an even more powerful locomotive was developed on its basis. This was the 4000 “Big Boy” class, which had two additional driving axles. Shortly thereafter, Otto Jabelman revised the Challenger, again incorporating innovations from the Big Boy. After the bigger sister received the class number 4884 based on its wheel arrangement, the new Challengers were now class 4664 instead of CSA.

The new batch now had a higher boiler pressure and smaller cylinders. A link between the chassis groups was installed, which improved the weight distribution. In addition, all locomotives were now equipped for use with passenger trains. The seven-axle tenders now held 56,000 pounds (25.4 t) of coal and 25,000 gallons (94,600 l) of water.

No. 3950 with a dynamometer car and test train at Sherman Hill
No. 3950 with a dynamometer car and test train at Sherman Hill
ALCO

The first revised Challengers were the 20 class 4664-3 locomotives built in 1942. In 1943, 25 4664-4s followed, the only difference being that they were 6,500 pounds heavier. Since less high-strength steel was available due to the war, these had a heavier frame. Six identical locomotives went to the D&RGW, which went to the Clinchfield Railroad in 1946. The last 20 Challengers formed the 4664-5 class, delivered in 1944. In order to be able to classify these in the number range from 3900, the CSA-1 and -2 were renumbered as 3800 and the new locomotives were given the numbers 3930 to 3949.

Although all Challengers were delivered coal-fired, as early as 1937 the six CSA-2s equipped for passenger service were converted to oil firing. Instead of 22,000 pounds (20 t) of coal, the oil tenders now held 6,000 gallons (22,700 l) of oil and also 18,000 gallons (68,000 l) of water. All other CSA-1s and -2s were also converted to oil in 1942 and 1943. In 1950, ten of these were converted back to coal, and in the same year they were converted back to oil again. 18 class 4664-4 and -5 locomotives were also converted to run on oil. Some locomotives were given numbers starting at 3700 to differentiate between the types of fuel. The still coal-fired Challengers later received an extension on the tender, which increased the capacity from 28 to 32 short tons

Most Challengers were scrapped between 1956 and 1961. Two are still preserved today, both of which belong to the subclass 4664-4. The 3977 is not operational and is based in North Platte, Nebraska. The 3985 was back in service from 1981 and parked in 2010 due to technical problems. After Big Boy No. 4014 got operational, it was officially retired in 2020. In 2022, however, it was donated to the non-profit organization “Railroading Heritage of Midwest America” together with two other locomotives and is now being refurbished by them.

VariantCSA-1, CSA-24664-3 and 44664-5
General
Built1936-19371942-19431944
ManufacturerALCO
Axle config4-6-6-4 (Challenger (Mallet)) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length121 ft 10 7/8 in
Wheelbase59 ft 11 in60 ft 4 1/2 in
Fixed wheelbase12 ft 2 in
Total wheelbase98 ft 10 1/2 in106 ft 8 in
Service weight566,950 lbs627,000 lbs634,500 lbs
Adhesive weight399,840 lbs403,700 lbs404,200 lbs
Total weight876,950 lbs1,063,500 lbs1,069,000 lbs
Axle load66,700 lbs67,300 lbs67,400 lbs
Water capacity18,000 us gal25,000 us gal
Fuel capacity44,000 lbs (coal)56,000 lbs (coal)
Power
Power sourcesteam
Estimated power5,000 hp (3,729 kW)5,800 hp (4,325 kW)
Optimal speed33 mph38 mph
Top speed70 mph
Starting effort97,305 lbf97,352 lbf
Power Plant
Driver diameter69 in
Boiler pressure255 psi280 psi
Expansion typesimple
Cylindersfour, 22 x 32 infour, 21 x 32 in
Boiler
Grate area108.3 sq ft132 sq ft
Firebox area548 sq ft602 sq ft604 sq ft
Tube heating area4,756 sq ft4,215 sq ft4,038 sq ft
Evaporative heating area5,304 sq ft4,817 sq ft4,642 sq ft
Superheater area1,650 sq ft2,355 sq ft1,741 sq ft
Total heating area6,954 sq ft7,172 sq ft6,383 sq ft
Calculated Values
steam locomotive
freight
passenger
Articulated
Arthur H. Fetters
Otto Jabelman
last changed: 06/2023
Union Pacific FEF-1 to FEF-3
United States | 1938 | 45 produced
FEF-1 No. 817 before conversion to oil firing in 1946
FEF-1 No. 817 before conversion to oil firing in 1946
collection LaMar M. Kelley

When William Jeffer, President of the Union Pacific, got stuck on an incline with his train, the initial order for the FEF series came about. The class 7000 locomotive used at the time with a 4-8-2 wheel arrangement was to be given a more powerful successor for mixed service, which led to the 4-8-4 wheel arrangement. This wheel arrangement was already in use on other US railroad companies and led to the designation “Four-Eight-Four”.

The first 20 FEF-1 class locomotives were delivered by ALCO in 1938 and had 77 inch diameter coupled wheels. Rolling resistance was reduced with roller bearings on all axles and tapered connecting rods ensured that the moving masses were reduced. This allowed them to travel at speeds of 110 mph with ease and without compromising safety.

FEF-3 No. 8444 in July 1981 in Colorado between Denver and Sterling
FEF-3 No. 8444 in July 1981 in Colorado between Denver and Sterling
Roger Puta

The following year, 15 FEF-2s were delivered, now with 80 inch coupling wheels, larger cylinders and higher boiler pressure. They were now cleared for 120 mph. Another ten FEF-3 followed in 1944, since no diesel locomotives were available for passenger trains due to the war.

The FEF series locomotives are known to produce between 4,000 and 5,000 hp at the drawbar and often traveled long distances in excess of 100 mph. In 1946 all were converted to oil firing, with the tenders now holding 6,550 gallons of oil instead of 25 short tons of coal.

In recent years, the locomotives were mainly used for freight trains before being retired at the end of the 1950s. Number 844 was the only US steam locomotive that was never officially retired and has since been used for excursion trips without major interruptions. In the meantime, it carried the number 8444 and is the only one of four surviving machines that is roadworthy.

VariantFEF-1FEF-2FEF-3
General
Built193819391944
ManufacturerALCO
Axle config4-8-4 (Northern) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length114 ft 2 5/8 in
Wheelbase49 ft 3 in50 ft 10 in
Fixed wheelbase21 ft 6 in22 ft
Service weight465,000 lbs478,640 lbs490,700 lbs
Adhesive weight270,000 lbs265,520 lbs270,300 lbs
Total weight849,350 lbs894,960 lbs912,250 lbs
Axle load67,500 lbs66,380 lbs67,575 lbs
Water capacity20,000 us gal23,500 us gal
Fuel capacity50,000 lbs (coal)
Power
Power sourcesteam
Estimated power4,800 hp (3,579 kW)5,200 hp (3,878 kW)5,400 hp (4,027 kW)
Optimal speed56 mph52 mph54 mph
Top speed110 mph120 mph
Starting effort55,129 lbf63,750 lbf
Power Plant
Driver diameter77 in80 in
Boiler pressure260 psi300 psi
Expansion typesimple
Cylinderstwo, 24 1/2 x 32 intwo, 25 x 32 in
Boiler
Grate area100.2 sq ft
Firebox area479 sq ft442 sq ft512 sq ft
Tube heating area4,118 sq ft3,971 sq ft3,782 sq ft
Evaporative heating area4,597 sq ft4,413 sq ft4,294 sq ft
Superheater area1,473 sq ft1,900 sq ft1,400 sq ft
Total heating area6,070 sq ft6,313 sq ft5,694 sq ft
Calculated Values
steam locomotive
express
passenger
freight
last changed: 04/2023
Union Pacific class 4000 “Big Boy”
United States | 1941 | 25 produced
No. 4002 in December 1954 in Laramie, Wyoming
No. 4002 in December 1954 in Laramie, Wyoming
A. Poschman / collection Taylor Rush

After the success of the Challenger, the Union Pacific planned to have only one locomotive haul express freight trains on Wasatch Grade and Sherman Hill in the future. To haul trains of 3,600 short tons and over it was calculated that an adhesive mass of 540,000 pounds would be required. The grate area should be large enough to be able to develop high power even with inferior coal. This required eight coupled axles and also four carrying axles in order to be able to carry a sufficiently strong boiler. At the same time, the locomotives should be designed for a speed of 80 mph

The locomotive developed in this way was the heaviest, but not the most powerful, conventional steam locomotive of all time. Like most modern American articulated locomotives, they had four cylinders with simple steam expansion and were therefore no true Mallets. The running numbers started from 4000, in fact the class was given the designation 4884 due to the lack of a name for the wheel arrangement. The Union Pacific first wanted to officially call it “Wasatch”, but the unofficial name “Big Boy” prevailed. In 1941, 20 class 4884-1 locomotives were built and in 1944 five more class 4884-2 locomotives.

In order to allow encounters between two Big Boys, the gap between the tracks had to be increased in many curves. The chassis had no problems with tight corners. In practice, they also pulled trains of 6,000 short tons and often reached their permitted speed of 70 mph with lighter trains. The number 4005 was converted to oil firing, but was converted back to coal firing after a short time. They later received an extension on the tender that increased capacity from 28 to 32 short tons

In the 1950s, the Big Boys were replaced by the gas turbine locomotives. The last commercial journey with a freight train took place in 1959. The 20 locomotives of the first series all achieved a mileage of just over a million miles. A total of eight Big Boys still exist today. The 4014 was the only one to be rebuilt and has been operational again since 2019. This makes it the most powerful operational steam locomotive today.

Variant4884-14884-2
General
Built19411944
ManufacturerALCO
Axle config4-8-8-4 (Big Boy (Mallet)) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length132 ft 9 5/16 in
Wheelbase72 ft 5 1/2 in
Fixed wheelbase18 ft 3 in
Total wheelbase117 ft 7 in
Service weight762,000 lbs772,250 lbs
Adhesive weight540,000 lbs545,200 lbs
Total weight1,189,500 lbs1,208,750 lbs
Axle load67,800 lbs
Water capacity24,000 us gal25,000 us gal
Fuel capacity56,000 lbs (coal)
Power
Power sourcesteam
Indicated power7,150 hp (5,332 kW)
Estimated power6,900 hp (5,145 kW)
Optimal speed34 mph32 mph
Top speed70 mph
Starting effort135,375 lbf
Power Plant
Driver diameter68 in
Boiler pressure300 psi
Expansion typesimple
Cylindersfour, 23 3/4 x 32 in
Boiler
Grate area150.3 sq ft150 sq ft
Firebox area704 sq ft720 sq ft
Tube heating area5,185 sq ft5,035 sq ft
Evaporative heating area5,889 sq ft5,755 sq ft
Superheater area2,466 sq ft2,043 sq ft
Total heating area8,355 sq ft7,798 sq ft
Calculated Values
steam locomotive
freight
Articulated
Otto Jabelmann
last changed: 03/2023
Western Pacific class TP-29
United States | 1908 | 36 produced
No. 94 in 1958 on the streets of Oakland California
No. 94 in 1958 on the streets of Oakland California
collection Taylor Rush

The first 16 of these oil-fired ten-wheelers were delivered to the Western Pacific in 1908, followed by 20 more the following year. ALCO-Brooks asked for a price of between 13,247 and 14,585 dollars per locomotive. These locomotives opened passenger service through the Feather River Canyon in 1910. They were soon retrofitted with superheaters. Most were retired in the thirties or fourties. The 94 was in service until 1953, featured at the Western Pacific 50th anniversary celebrations, and pulled excursion trains from 1979 to 1986.

Variantas builtsuperheated
General
Built1908-19091909
ManufacturerALCO
Axle config4-6-0 (Ten-wheeler) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Wheelbase24 ft 4 in
Fixed wheelbase13 ft 6 in
Total wheelbase57 ft 11 in
Service weight181,000 lbs
Adhesive weight135,000 lbs
Total weight308,460 lbs313,000 lbs
Axle load45,000 lbs
Water capacity6,000 us gal7,000 us gal
Fuel capacity3,070 us gal (oil)3,019 us gal (oil)
Power
Power sourcesteam
Estimated power1,000 hp (746 kW)1,400 hp (1,044 kW)
Optimal speed22 mph31 mph
Starting effort29,093 lbf
Power Plant
Driver diameter67 in
Boiler pressure200 psi
Expansion typesimple
Cylinderstwo, 21 x 26 in
Boiler
Grate area33.5 sq ft33.6 sq ft
Firebox area193 sq ft228 sq ft
Tube heating area2,404 sq ft2,017 sq ft
Evaporative heating area2,597 sq ft2,245 sq ft
Superheater area568 sq ft
Total heating area2,597 sq ft2,813 sq ft
Calculated Values
steam locomotive
passenger
last changed: 07/2023
Union Pacific class 9000
United States | 1926 | 88 produced
No. 9000 in March 1955 in North Platte, Nebraska
No. 9000 in March 1955 in North Platte, Nebraska
Arthur Stensvad / collection Taylor Rush

Since articulated freight locomotives in the 1920s did not yet reach the same speeds as ten-coupled locomotives, Union Pacific had the class 9000 developed with six coupled axles in one frame. The unique wheel arrangement with a four-wheel leading bogie, six sets of drivers and a two-wheel trailing truck was called “Union Pacific” by the UP. The 1926 prototype was officially given the class designation UP-1, while further batches were designated UP-2 to UP-5.

Only the fourth driving axle had no wheel flanges, but the first and sixth could be moved laterally by two inches. In order to be able to use the steam from the large boiler, three cylinders were installed. The middle one was offset upwards at an angle and was controlled by the outer cylinders via a Gresley valve gear.

In addition to the UP, two subsidiaries also received additional locomotives of this type, so that the total number ultimately reached 88. These were eight on the Oregon–Washington Railroad and Navigation and 15 on the Oregon Short Line Railroad. Although they were only intended for speeds of 35 mph (56 km/h), they often reached 45 to 50 mph with freight trains and could easily reach 60 mph (97 km/h) while running steadily.

Their area of operations focused on Nebraska, where they increased the speed of freight trains in the flat land. However, it became apparent that the Gresley valve gear's friction bearings were subject to high levels of wear. Only in eight of the oldest locomotives was this replaced with a Walschaerts valve gear and in the machines built from 1928 the Gresley valve gear was given roller bearings.

During the Second World War they had to work hard and were no longer adequately maintained. This meant that some were set aside during the war. The entire class was withdrawn from service between 1953 and 1956. The only surviving locomotive is the prototype number 9000. It is not operational and belongs to the Railway & Locomotive Historical Society in Pomona, California.

General
Built1926-1930
ManufacturerALCO
Axle config4-12-2 (Union Pacific) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length104 ft 4 in
Wheelbase52 ft 4 in
Fixed wheelbase30 ft 8 in
Total wheelbase91 ft 6 in
Service weight496,500 lbs
Adhesive weight354,000 lbs
Total weight807,099 lbs
Axle load60,000 lbs
Water capacity18,000 us gal
Fuel capacity44,000 lbs (coal)
Power
Power sourcesteam
Indicated power4,915 hp (3,665 kW)
Optimal speed32 mph
Top speed60 mph
Starting effort97,664 lbf
Power Plant
Driver diameter67 in
Boiler pressure220 psi
Expansion typesimple
Cylindersthree, center: 27 x 32 in
outside: 27 x 31 in
Boiler
Grate area108.3 sq ft
Firebox area591 sq ft
Tube heating area5,262 sq ft
Evaporative heating area5,853 sq ft
Superheater area2,560 sq ft
Total heating area8,413 sq ft
Calculated Values
steam locomotive
freight
last changed: 02/2024
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