Union Pacific's Articulateds
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By Richard F. Cole
Western Prototype Modeler, May-June 1975
[photo caption] No. 3933 at Sidney, Nebraska on November 10, 1956, was one of the last and heaviest "Challengers" built for the Union Pacific in 1944. Fast, powerful and handsome the 3933 stands beside one of the roads numerous steel coaling towers.
The Union Pacific, through its long and glorious history has had many claims to fame. Promontory Point, Sherman Hill, Echo Canyon, The "Overland Limited," The "City" Trains, Gas Turbines and Super Diesels are all synonymous with the Union Pacific. But perhaps the most interesting facet of the roads historic past is the fleet of 241 Articulated Steam Locomotives that once plied the rails of this transcontinental carrier. While each class deserves a separate article in its own right, the following is intended to be a simplified photographic, technical and historical coverage of these great locomotives.
It was in December of 1909 that the articulated locomotive was introduced on the Union Pacific in the form of three Baldwin built compound 2-8-8-2s, road numbers 2000-2002, with 57" drivers, 26" and 40" diameter by 30" cylinders and small rectangular tenders. These slow moving but sure footed mallets immediately went into service on the Union Pacific's Wyoming grades. Shortly thereafter these locomotives were transferred to the Oregon-Washington Railroad and Navigation Company (O.W.R. & N.) for use in the "Blue Mountains." In 1915 these locomotives were renumbered 3600-3602. They were transferred to the Oregon Short Line (O.S.L.) in 1917 where they were renumbered to 3700-3702. These locomotives worked in helper service until 1928 when they were retired and scrapped.
Three nearly identical Baldwin locomotives were built in 1910 for the Oregon Railway and Navigation Company (O.R. & N). The locomotives arrived as road numbers 450-452. In that same year the Oregon, Washington and Northern Idaho lines were reorganized as the O.W.R. & N. In 1911 the 2-8-8-2 compounds were renumbered to 700-702. In 1915 the locomotives were renumbered to 3800-3802. The 2-8-8-2s worked in the Blue Mountains and in 1918 were equipped with 6,000 gallon auxiliary water tenders. In 1928 the compounds were withdrawn from service and scrapped.
As built, Nos. 2000-2002 and 450-452 were equipped with 9,000 gallon, 10-ton (increased to 15-tons) rectangular tenders. The small water capacity accounts for Nos. 450-452 (3800-3802) acquiring auxiliary water tenders in 1918. The auxiliary water tenders could be uncoupled for ease in turning the locomotives.
Basic specifications for all six 2-8-8-2s are shown in Table I.
| TABLE I | |
| Cylinders | 26" & 40" diameter by 30" stroke |
| Drivers | 57" diameter |
| Boiler Pressure | 200 PSIG |
| Grate Area | 68.4 square feet |
| Weight on Drivers | 394,150 pounds |
| Weight of Total Engine | 425,900 pounds |
| Tractive Effort | 94,880 pounds |
| Valve Gear | Walschaert |
The 2-8-8-2s were almost identical to Southern Pacific's locomotives Nos. 4000 and 4001, also built in 1910. The Southern Pacific and Union Pacific were both under "Harriman" control and the 2-8-8-2s were considered "Harriman Standard" locomotives.
The boilers for the 2-8-8-2s were built in two sections with the front section serving as a feedwater heater. This section received the feedwater from the injectors, preheating it before entering the rear section which comprised the boiler. While injectors do heat the feedwater, the feedwater heater further increased the temperature of the water, thereby increasing thermal efficiency. From the boiler, saturated steam went to the rear high pressure cylinders, and then it was exhausted to a reheater in the smokebox and then entered the front low pressure cylinders. All six locomotives were hand fired.
While the 2-8-8-2s were in service for about 18 years, they were only considered moderately successful. Poor combustion due to a small grate area was partially relieved by the addition of draft boxes behind the rear drivers. This allowed more air to pass through the grates and improved combustion. However, steam generation was only moderate and the compounds were slow moving creations. At about 18 M.P.H. they showed nearly 2500 Indicated Horsepower.
The second stage of articulated development on the Union Pacific began with the delivery of fifteen 2-8-8-0s, road Nos. 3600-3614, built by Alco in 1918. These locomotives had 26" and 41" diameter by 32" cylinders, 57" drivers and much larger boilers than the earlier 2-8-8-2s. Their tenders were of the eight wheel Vander-built type holding 20 tons of coal and 12,000 gallons of water. They immediately went to work on "Sherman Hill" and other mainline grades.
[photo caption] Compound 2-8-8-0 No. 3646 in temporary storage at Cheyenne, Wyoming on March 30, 1941. This locomotive will be simpled, have the twin air compressors moved to the pilot deck, receive a larger stack, be equipped with a 12 wheel tender and be renumbered to 3546. She will be retired in 1954.
U.P. Locomotives 3615-3633 came from Alco in 1920. The 3634-3638 series locomotives arrived in 1922. Nos. 3639-3643 were received in 1923. In 1924 Nos. 3645-3664 were built. O.W.R. & N. locomotives 3803-3805 were built by Alco in 1923. O.S.L. number 3703 arrived in 1918 and Nos. 3704-3705 in 1923. All locomotives had the same size cylinders, drivers, tenders and Walschaert Valve Gear and Schmidt Superheaters.
It is interesting to note that during the same period of time that the 57" drivered, compound 2-8-8-0s were being constructed, the Union Pacific was also accumulating a fleet of 63" drivered 2-10-2. With little of commonality in appearance, except for their tenders, the engines were of very similar boiler size and horsepower output. The idea behind this was very simple, use the faster 2-10-2s on level stretches and the 2-8-8-0s on tough grades where high drawbar pull was needed. This was truly the drag freight era.
[photo caption] Single expansion 2-8-8-0 is shown at Reith, Oregon on July 7, 1939. This oil fired articulated still carries its original 0. W. R. & N. number of 3805; she will have her two air compressors moved to the pilot deck and finish her career as No. 3569.
[photo caption] On June 2, 1950, No. 3500 shown at Salt Lake City, Utah exemplifies the 2-8-8-0 in its ultimate form on the Union Pacific. The large relatively flat snow plow is similar to those extensively used on the road's 2-10-2s and F-7 diesels in heavy snow territory.
Slow but dependable and powerful, the 2-8-8-0s were the main power used over "Sherman Hill" until the arrival of the eighty-eight 67" drivered, 4-12-2s, 9000 class between 1926 and 1930. The 4-12-2s which began the era of big, fast, powerful steam locomotives on the Union Pacific, could pull about the same tonnage as a compound 2-8-8-0 but at nearly twice the speed! On the long, hard uphill pull, the compound 2-8-8-0s could do only about 10 to 12 M.P.H.
Basic specifications for the 2-8-8-0 "Compounds" are shown in Table II.
| TABLE II | |
| Cylinders | 26" and 41" diameter x 32" stroke |
| Drivers | 57" diameter |
| Boiler Pressure | 210 PSIG, later 218 PSIG |
| Grate Area | 88.2 square feet |
| Weight on Drivers | 460,700 pounds to 472,000 pounds |
| Weight of Total Engine | 491,500 pounds to 502,500 pounds |
| Tractive Effort | 106,900 pounds |
| Valve Gear | Walschaert |
| Stoker Engine | Duplex D-1 |
In the mid 1930s, the Union Pacific, in an effort to speed up the 2-8-8-0s, began rebuilding them as single expansion locomotives. By 1946 the rebuilding program was completed and all 70 locomotives had been "simpled." Among the changes made to the locomotives were increasing the driver diameter from 57" to 59" by applying thicker tires on the existing driver centers. The air compressors were moved to the pilot deck and mounted behind shields, but this was done after each engine was simpled. All of the locomotives had Worthington type SA feedwater heaters applied. Some originally had Worthington type BL feedwater heaters and others had none. Many 2-8-8-0s had large 12-wheel, 18,000 gallon Vanderbilt tenders applied and all had larger stacks added. These improvements extended their lives, with the last of the 2-8-8-0s being retired in 1954.
The 2-8-8-0s could be found almost anywhere at one time or another except for the Kansas Division. They were also very rarely seen on the Nebraska Division but did drift as far eastward as Sidney on a few occasions. In general it was very seldom when a 2-8-8-0 roamed further east than Cheyenne or Denver. All of the 2-8-8-0s were renumbered to the 3500 series after simpling to ease the task of locomotive assignments. The simples were faster than the compounds and were assigned to the higher speed freights. The final road numbers were 3500-3569. One of the last assignments for the 2-8-8-0s was as "Sherman Hill" helpers.
Basic specifications for the 2-8-8-0 "Simples" are shown in Table III.
| TABLE III | |
| Cylinders (4) | 23" diameter by 30" stroke |
| Drivers | 59" diameter |
| Boiler Pressure | 218 PSIG |
| Grate Area | 88.2 square feet |
| Weight on Drivers | 474,980 pounds |
| Weight of Total Engine | 505,480 pounds |
| Tractive Effort | 99,840 pounds |
| Valve Gear | Walschaert |
| Stoker Engine | Duplex D-1 |
Following the success of the three cylinder 4-12-2s, the Union Pacific wanted a locomotive of similar speed and power, but without the long rigid wheelbase of the 9000 class. Despite the use of lateral motion devices on the 4-12-2s drivers, there were areas where 30'-8" driving wheelbase locomotives dare not tread. While restricted to mainline use the 9000 class was not confronted with severe track curvature, however maintenance costs on the locomotives rose sharply when they were forced to sustain 50 M.P.H. speeds. These problems led directly to phase 3 of articulated locomotive development on the Union Pacific, namely the high speed, single expansion 4-6-6-4 "Challenger" Type in 1936. By the time that Alco had delivered the last 4-6-6-4 in 1944, the Union Pacific had 105 "Challengers," the largest roster of such engines ever owned by a single railroad.
The early or light "Challengers" were purchased in three groups: Nos. 3900-3914 in 1936, Nos. 3915-3933 in 1937 and Nos. 3934-3939 also in 1937. Each group varied in total engine weight, but all had Walschaert Valve Gear, Type A Superheaters, 255 PSIG boiler pressure and 69" "Box-Pok" drivers. Locomotives 3900-3939 were all built as coal burners, but Nos. 3934-3939 were converted to oil burners right after being received from Alco. The tenders were of a semi-Vanderbilt design with 6 wheel trucks and an 18,106 gallon capacity with 22 tons of coal or 6,000 gallons of oil.
The "Challenger" type was developed and named by the Union Pacific. The first forty locomotives had built-up frames, tube pilots and 12-wheel "Semi-Vanderbilt" tenders. With deeply arched cab roofs, headlights centered on the smoke-box front and single stacks, these locomotives carried on the styling then prevalent on the U.P. The "Challengers" had roller bearing lead, trailing and tender trucks but the driving axles had friction bearings. In 1948-1949 about ten of the 4-6-6-4s had their built-up front engine frames replaced with cast steel engine beds. Some "Challengers" had Commonwealth swing gate pilots, new air compressor shields and larger front sandboxes applied later in their careers.
Early in 1944 the 3900-3939 series were renumbered to 3800-3839. Nos. 3800-3815 were converted from coal to oil in 1943. In 1949 some of the oil burners were converted back to coal and renumbered to the 3700 series. In 1950 these engines were again converted to oil and regained their 3800 series numbers again. The Union Pacific used separate oil tanks which were lowered into the tender coal bunkers when conversion to oil was necessary. The tanks were equipped with lifting lugs for easy removal. Wood 2X4s were fitted into channels attached to the lower portion of the oil tank and acted as spacers. The oil tanks were contoured to fit the tender coal bunkers. The most difficult part of conversion from coal to oil firing and back again was the firebox work. The entire process could be completed in a few days.
[photo caption] 4-12-2 No. 9087 shown here at Council Bluffs, Iowa on September 7, 1953 was the last "Union Pacific" type locomotive delivered. This 1930 Alco product weighed 515,000 pounds less tender and developed 96,650 pounds of tractive effort with 67" drivers.
[photo caption] The first 4-6-6-4 to be numbered 3936 is shown here at Shoshone, Idaho on July 18, 1938. The light, oil burning "Challenger" was built by Alco in 1937. In 1944 this locomotive was renumbered to 3836.
[photo caption] Light "Challenger" No. 3838 has a cast steel front engine bed, new air compressor shield, steps from pilot to platform above air compressors, sand pipes to each driver and the check valves relocated to the boiler top. Pocatello, Idaho, April 19, 1953.
[photo caption] "Big Boy" No. 4012 at Laramie, Wyoming on October 25, 1958. Those steel coal boards allowed the tenders to carry an extra 4 tons of coal. The chain drives on the front mechanical lubricators were an exclusive Union Pacific feature added after numerous failures of the original link drives. Today No. 4012 is at "Steamtown U.S.A." in Bellows Falls, Vermont.
[photo caption] No. 3936 at Cheyenne, Wyoming on September 28, 1950. She weighs in at 634,500 pounds less the tender and develops 97,350 pounds of tractive effort with 69" drivers. The strong resemblance between the "Big Boys" and heavy "Challengers" is amazing.
[photo caption] Heavy, oil burning "Challenger" No. 3701, was built as No. 3931. The date is October 2, 1954 and the place is Laramie, Wyoming. She was converted to oil in 1952.
In general the light 4-6-6-4s were used system-wide, although they were rarely, if ever, seen on the Kansas Division. In their final years, the Nebraska Division was their home. These locomotives served the Union Pacific well during their years of service ending in 1958.
Basic specifications for the light series 4-6-6-4s are shown in Table IV.
| TABLE IV | |
| Cylinders (4) | 22" diameter by 32" stroke |
| Drivers | 69" diameter |
| Boiler Pressure | 255 PSIG |
| Grate Area | 108.25 square feet |
| Weight on Drivers | 386,000 pounds, 403,000 pounds and 400,000 pounds respectively for the three groups. |
| Weight of Total Engine | 566,000 pounds, 582,000 pounds and 576,400 pounds respectively for the three groups. |
| Tractive Effort | 97,400 pounds |
| Valve Gear | Walschaert |
| Stoker Engine | Type "BK" |
In 1941, in an attempt to further increase the tonnage capacity per locomotive and eliminate helpers, the fourth and greatest stage of articulated development occurred with the introduction of the 4000-4019 series, 4-8-8-4 "Big Boys". The 68" drivered locomotives had four 23-3/4" diameter by 32" cylinders, 150 square feet of grate area and 300 PSIG boiler pressure and Type "E" Superheaters.
Alco built the completely modern articulateds with roller bearings on all axles, cast steel engine beds, twin stacks, cast steel pilots and "Box-Pok" drivers. With an overall length of 132'-9-7/8" and a weight of 1,189,500 pounds with engine and tender filled, they ranked as the world's largest reciprocating steam locomotives, until delivery of the 1944, 4020-4024 series.
The tenders for the 4000-4019 series were of the pedestal bed type similar to those developed for the 820-834 series 4-8-4s of 1939. The principle difference was that the new tenders had a larger capacity of 24,000 gallons and 28 tons. As with the locomotives, roller bearings were used throughout. The tenders weighed 171,500 pounds empty and 427,500 pounds with a full load of coal and water.
Fortunately the 4-8-8-4s did not follow the styling used on the light 4-6-6-4s. Instead larger sandboxes, twin stacks, cast pilots, more graceful cabs and handsome pedestal bed tenders were used. This was a great improvement and caused the 4-8-8-4s to be among the handsomest steam locomotives ever built.
With a tractive effort of 135,375 pounds, the high speed 4-8-8-4 substantially increased tonnage ratings on the Wyoming Division which was their home. The 4000s were designed to haul 3600 tons over Sherman Hill but in their final years were rated at 4450 tons over the 1.14 percent ruling grade!
To enable the 4000s to be turned, new 135 foot turntables were installed at Ogden, Utah; Green River, Laramie and Cheyenne, Wyoming and special extended stalls were added to the roundhouses. These were the world's largest turntables.
With a maximum drawbar horsepower of 6,290, the 4-8-8-4s could outpull four F-7 units (6,000 H.P. total, A-B-B-A) at any speed from about 19 M.P.H. to 60 M.P.H. At 30 M.P.H. the 4000s could develop a drawbar pull of about 75,000 pounds versus 66,400 pounds for an A-B-B-A, F-7 diesel combination. The 4-8-8-4s developed their best horsepower at about 30 M.P.H. and 60 M.P.H. was their highest practical speed although they did hit 80 M.P.H. on a couple of occasions. In service over "Sherman Hill" the 4-8-8-4s averaged between 20 to 30 M.P.H. with speeds sometimes dropping down to 15 M.P.H.
Basic specifications for the 4000-4019 series 4-8-8-4s are shown in Table V.
| TABLE V | |
| Cylinders (4) | 23-3/4" diameter by 32" stroke |
| Drivers | 68" diameter |
| Boiler Pressure | 300 PSIG |
| Grate Area | 150 square feet |
| Weight on Drivers | 540,000 pounds |
| Weight of Total Engine | 762,000 pounds |
| Tractive Effort | 135,375 pounds |
| Valve Gear | Walschaert |
| Stoker Engine | Standard M.B. |
| Total Weight of Engine and Tender | 1,189,500 pounds |
In 1942 the Union Pacific refined the 4-6-6-4s by having the 3950-3969 series built by Alco. This began the heavy 4-6-6-4s which would total 65 by 1944, consisting of 3 groups. These 1942 "Challengers" incorporated many of the modern features used on the 1941 4-8-8-4s. Among these were cast steel engine beds, cast steel pilots, roller bearings throughout and pedestal type 4-10-0 tenders. They had 69" diameter drivers, 280 PSIG boiler pressure and 132 square feet of grate area. Type "E" Superheaters were used as well as twin stacks and the larger more graceful cabs.
1943 saw the 3975-3999 series appear on U.P. rails. They were almost identical to the 3950-3969 series. Nos. 3930-3949, the heaviest of the "Challengers", were constructed in 1944. This group of locomotives, while identical in external appearance, differed from the 3950-3969 and 3975-3999 series by having Type "A" Superheaters and different boiler tube and flue arrangements. In 1945 Nos. 3975-3980 were converted to oil firing. In 1946 Nos. 3975-3979 were painted in two-tone grey and equipped with "Smoke Wings" and placed in Oregon and Washington passenger service, where their short rigid wheelbases were well suited to the track curvature.
Basic specifications for the 3950-3969, 3975-3999, and 3930-3949 series 4-6-6-4s are shown in Table VI.
| TABLE VI | |
| Cylinders (4) | 21" diameter x 32" stroke |
| Drivers | 69" diameter |
| Boiler Pressure | 280 PSIG |
| Grate Area | 132 square feet |
| Weight on Drivers | 403,700 pounds, 407,500 pounds and 406,200 pounds respectively for the three groups. |
| Weight of Total Engine | 627,000 pounds, 633,500 pounds and 634,500 pounds respectively for the three groups. |
| Tractive Effort | 97,350 pounds |
| Valve Gear | Walschaert |
| Stoker Engine | Standard M.B. |
In 1952 eight of the 3930-3944 series 4-6-6-4s were converted from coal to oil firing and renumbered in the 3700-3707 series. Nos. 3975-3984, which had already been converted to oil, were renumbered to 3708-3717 in 1952. All 18 of these locomotives were heavy "Challengers".
The "Challengers" were less powerful but about 10 M.P.H. faster than the "Big Boys". However the "Big Boys" were considered free steamers while the "Challengers" were harder to fire. A "Challenger" made a good helper for a "Big Boy" powered freight since both were considered fast freight power. Many times a 4-6-6-4 would lead a 4-8-8-4 on a mile long freight over "Sherman Hill." The heavy "Challengers" however, spent most of their final year on the Nebraska Division along with the older, light "Challengers".
[photo caption] A 1944 model 4-8-8-4 and one of the group of five world's heaviest reciprocating locomotives. Although identical in appearance to the 1941 series, they were heavier. This particular locomotive is still owned by the Union Pacific. Laramie, Wyoming: October 2, 1954.
[photo caption] Compound 2-8-8-2 No. 3670 at Rock Springs, Wyoming on September 23, 1947. This was former Norfolk and Western class Y-3, No. 2030. The end is near for this 1919 mallet.
[photo caption] Another outcast, this time its former Chesapeake and Ohio No. 1549, an Alco product of 1924. She now carries Union Pacific No. 3573 at Rock Springs, Wyoming on September 23, 1947. This locomotive has been extensively rebuilt and bears little resemblance to when it arrived on U.P. rails. This locomotive will be retired in a couple of months. The big tender holds 25,000 gallons of water and 25 tons of coal.
In 1944 the final chapter of Articulated steam locomotive development was written on the Union Pacific. During this year Alco built the 4020-4024 series 4-8-8-4s. They were identical to the 4000-4019 series with the exception of Type "A" Superheaters, a different location for the finned aftercooling piping, an increase of 10,250 pounds in locomotive weight and larger 25,000 gallon, 28 ton pedestal type tenders (the same as on the 1942, 1943 and 1944 series 4-6-6-4s). The tenders weighed 172,300 pounds empty and 436,500 pounds filled.
A different arrangement of boiler tubes and flues gave a slight decrease in heating surface from the 4000-4019 series of 1941. These five additional 4-8-8-4s brought the total to twenty-five. This essentially concluded the development of articulated steam power steam locomotives on the Union Pacific.
From 1941 to 1959 the 4-8-8-4s operated over "Sherman Hill" with one and sometimes two locomotives assigned to a train. Fast, rugged, dependable, powerful and well-liked by the engines crews seems to sum up their role in the long chain of U.P.
At 7:55 PM on July 21, 1959 when No. 4015 arrived at Cheyenne from Laramie, steam power in regular service on the "Overland Route" concluded.
Basic specifications for the 4020-4024 series 4-8-8-Ts are shown in Table VII.
| TABLE VII | |
| Cylinders (4) | 23-3/4" diameter by 32" stroke |
| Drivers | 68" diameter |
| Boiler Pressure | 300 PSIG |
| Grate Area | 150 square feet |
| Weight on Drivers | 545,000 pounds |
| Weight of Total Engine | 772,250 pounds |
| Tractive Effort | 135,375 pounds |
| Valve Gear | Walschaert |
| Stoker Engine | Standard M.B. |
| Total Weight of Engine and Tender | 1,208,750 pounds |
In 1945, an acute motive power shortage caused the Union Pacific to search for additional locomotives to meet their immediate needs. They were able to purchase five, 1919 vintage Alco built compound 2-8-8-2s. These locomotives which were Norfolk and Western class Y-3 were among the oldest of their wheel arrangement on the N. & W. and were obsolete compared with the newer 2-8-8-2 compounds. With 57" drivers the compounds were powerful but slow. They were renumbered to 3670-3674 upon arrival on the Union Pacific.
The 2-8-8-2s at first operated from Idaho Falls to Butte, Montana. In the fall of 1946 they were transferred to the Wyoming Division. All 5 locomotives were scrapped by late in 1947. Being compounds and having Baker Valve Gear it is not surprising that the 2-8-8-2s were short lived. Remember that the entire class of 70 Union Pacific 2-8-8-0s had been rebuilt from compounds to simple articulateds in an attempt to increase speeds. Apparently the Union Pacific did not consider the ex N. & W. 2-8-8-2s worth rebuilding.
Basic specifications for the 3670-3674 series 2-8-8-2s are shown in Table VIII.
| TABLE VIII | |
| Cylinders | 25" & 39" diameter by 32" stroke |
| Drivers | 57" diameter |
| Boiler Pressure | 270 PSIG |
| Grate Area | 96.3 square feet |
| Weight on Drivers | 485,200 pounds |
| Weight of Total Engine | 539,000 pounds |
| Tractive Effort | 114,154 pounds compound |
| Valve Gear | Baker |
| Stoker Engine | Duplex |
During 1945 the Union Pacific also purchased 30 second-hand simple 2-8-8-2s from the Chesapeake and Ohio. 19 of these locomotives were built by Alco in 1924 and the other eleven by Baldwin in 1926. These locomotives were class H-7 on the C. & O. and with their 57" drivers were too slow and replaced by a 1930 group of forty, 69" drivered 2-10-4 Texas type locomotives. Being surplus power in 1945, the H-7's were available for purchase by the Union Pacific and renumbered to 3570-3599 series.
Eleven of the locomotives were rebuilt by the Union Pacific while the remaining 19 received only enough attention to keep them running. The 11 rebuilds were changed greatly in appearance and emerged from the shops looking like a cross between the 3500 series simple 2-8-8-0s and the 3800 series light 4-6-6-4s. While the rebuilt locomotives were an improvement, still the 2-8-8-2s were too slow for Wyoming Division service where they were assigned until being retired. The 2-8-8-2s were used singularly and double headed over "Sherman Hill" holding up all traffic behind them. When doubleheaded with the 4-6-6-4s and 4-8-8-4s they could not generate sufficient speed and were not successful as helpers. By the end of 1947 all of the 2-8-8-2s were retired.
Basic specifications for the 3570-3599 series simple 2-8-8-2s are shown in Table IX.
| TABLE IX | |
| Cylinders (4) | 23" diameter by 32" stroke |
| Drivers | 57" diameter |
| Boiler Pressure | 225 PSIG |
| Grate Area | 112.2 square feet |
| Weight on Drivers | 493,910 pounds to 504,500 pounds |
| Weight of Total Engine | 572,330 pounds to 584,600 pounds |
| Tractive Effort | 113,595 pounds |
| Valve Gear | Walschaert |
| Stoker Engine | Duplex or Standard |
From 1909 to 1959 there was four cylinder steam power of four different wheel arrangements, both compound and simple 2-8-8-2s and 2-8-8-0s and simple 4-6-6-4s and 4-8-8-4s, operating on the Union Pacific. The largest total of 235 articulateds was from 1945 to 1947 when the second hand 2-8-8-2s were being used. July 21, 1959 was a sad day when the fires were dropped for the last time on 4-8-8-4 No. 4015. It is now sixteen years since an articulated operated in revenue service on the Union Pacific but the memory of these thundering leviathans lingers on.
[photo caption] O. R. & N. Number 451 at the Albina Shops, Portland, Oregon, in 1911 just prior to being renumbered to 701. The locomotive still has its extended piston rods and covers on front cylinders. Draft boxes, coal boards, and auxiliary tenders will he added later. This is an H. H. Arey photo from the collection of R. H. Kindig. This photo was received late and is somewhat out of order with the text but it was felt to be a most important photo and was included at the end for this reason.
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