Union Pacific Steam Locomotive Wheel Arrangements

The second attempt at bigger power on the UP was the purchase of a Baldwin 2-8-0 in 1868. This 45 ton "monster" was shipped west for Wyoming grade duty while the road was still under construction. Tests proved so successful with this engine that two more were bought the following year. All worked out of Cheyenne and eventually were scrapped in 1902 and 1904.

These engines had Box tenders and burned wood. Later the tenders were equipped for coal use and had an 8 ton, 2244 gallon water capacity.

The next series of fifteen Baldwin Consolidations came to the road in 1881. These were a little heavier than the 1868 models and were also assigned to Wyoming and Utah grades. These were followed in 1882 by a series of Danforth and Cooke locomotives and through the years until the last one was turned out in 1910 by Brooks, Cooke, Taunton, and Baldwin delivered more than 400 of the type for freight use.

All the early 2-8-0's sported huge Diamond stacks even after conversion to coal operation in the early 1870s. Distinctive, too, was the horizontal slatted pilots, typical of UP power for years until the first World War period.

The first move away from the "old" practices in power design was on the 1890 series, 1600-1609, Cooke locomotives. These had short smokeboxes, modified Diamond stacks, injectors, single-guide type crossheads, steam driven driver brakes plus air brakes, on some units. The tender was a Box type with 5000 gallon water and fifteen ton coal capacity.

The Brooks models of November 1898, were similar to the Schenectady series but had simple cylinders and spoked wheels on the engine truck.

The Schenectady cross-compound Consolidations of September 1898, numbers 1320 and 1321, had the regular Alligator crosshead with two guides. Stephenson valve gear was used on all the system's simple Consolidations except the later 400 and 500 series which used Walschaerts after rebuilding.

The cross-compounds were rebuilt simple in June 1909, at Omaha. There were only two of this particular class, the 1320 and 1321.

In August 1900, Baldwin took a hand in compound Consolidations with the 1620-99 series Vauclain compounds. These locomotives sported extended piston rods from both steam cylinders and employed a cast-steel crosshead radically different from the Alligator type. The tender was the same as earlier 2-8-0's and the cab was of steel frame and wood paneled type. The Vauclain compounds, when simpled, were outfitted with Walschaerts valve gear. The tender held 6000 gall ons of water and eleven tons of coal. The 1620-1621 were the first break-away from the horizontal pilots.

The Vauclain compounds, when simpled, were outfitted with Walschaerts valve gear. The 1620-1621 were built with "Vanderbilt Boilers" which proved unsatisfactory and regular boilers were installed. Many of this particular type are on display in parks along the system. This series also introduced the then new Baldwin lead truck with a vertical spring arrangement. This was never removed from the class and the remaining 2-8-0s still use it. The pilot beam was of wood, one of the last classes to use this type. An improved acetylene headlamp was used until the conversion during the first war. The locomotives were simpled in 1911-1920 and steel cabs applied in keeping with the system-wide cab rebuilding program.

Much publicity was made of the Baldwin compound 2-8-0s and many photos of the period show this class of locomotive in fast freight and even heavy passenger work. Maintenance charges and speed capabilities soon forced them into simple engines. Forerunners of the Harriman 2-8-0s were the Baldwin 1508-1521 compounds, built in October 1902.

One of the first steel cabs was applied to a 2-8-0 and resembled the conventional wooden varieties. Most wooden cabs on the type were replaced with steel cabs beginning in 1905-1907. Consolidations, being top freight power at the time, were equipped with acetylene headlights around December 1906.

In 1906 the first Rectangular tender was put on the line and applied to a 2-8-0. These tenders had a 9,000 gallon and 15 ton capacity and soon replaced all the older Box tenders on road service. These tenders were designed to eliminate certain bad-water district water plugs.

Cylindrical tenders were applied to later series of Consolidations beginning around 1908-1912. These first Vanderbilt tanks had 9 ton, 5400 gallon capacity. Vulcan and Andrews trucks were used on all of the type in later years.

Most distinctive of the road's many Consolidations were the Baldwin (old 1620-99) 400 series which featured tall stacks, steel cabs (added later), slim boilers, tall domes, Walschaert gear and, in later years, Cylindrical tanks. These were the mainstay of Nebraska branch lines and were assigned to branch varnish whenever the "doodlebug" gas·electrics of recent years broke down. For many years this type was the main power on the system and remained so on the Nebraska Division until the early 1920s, when the "Mikes" moved east.

The 400 series Baldwin Consolidations, built in 1901, were the first locomotives on the system to have the modern, wide fireboxes. Oil burners were first applied to 2-8-0s in 1924. Stokers were never applied to any of the type - they all remained "hand tampers," or "hand bombers." Most of the Consolidations were rebuilt several times during their lifetime and along the way acquired the standard inside valve cylinders, mechanical lubricators, center-mounted headlights, inside mounted bearing lead trucks, steel pilot beams, power reverse gear, and superheaters. The power reverse came in 1940-1942, and the superheaters way back in 1910-1916 and 1919-1923. The Baldwin 1906 series were the first locomotives on the line to have fireboxes mounted in the contemporary above-drivers manner.

During World War I, the Union Pacific leased some 900 class Consolidations from the Illinois Central for use on the Nebraska Division and they were returned after the war to the IC.

The 6084-6086 were the former "big" locomotives on the Las Vegas & Tonapah before the UP took over that road. They were assigned to the Los Angeles Division in later years for local work and switching duties.

A Ragonnet power reverse gear was installed on the 237 in November, 1928. The 460 had a Duplex back pressure gauge applied in 1929 and had a Schmidt superheater applied in January, 1919.

The Consolidations were never intended for passenger duty, but on occasion, system-wide, they pulled local varnish and the classic "mixed" trains. For years they were helpers on the mountain lines also and were assigned to yard duties from the twenties to present.

Some of the type still survive in stored serviceable condition. There are more Consolidations in parks along the UP than any other type.

The first Consolidation (2-8-0) wheel arrangement came to the UP as early as 1868 and that locomotive remained in service until 1904. Locomotives of this type were primarily built to handle freight trains; however, old photographs indicate they were used on non-priority passenger trains during their early service years. During the Harriman management, the UP and affiliated lines purchased hundreds of Consolidations between 1900 and 1908, all having the standard 57-inch drivers. This was the beginning for motive power designs that have become known as the Harriman Common Standard. Locomotives of this class were the super power of that era until replaced by larger power. Into the 1930-era many worked on main line runs where moderate gradients existed. Many were used in various yards for switching service, and continued to work main line local freight and branch line mixed train assignments until replaced by diesel locomotives in the mid-1950s. The majority of this class served the railroad for fifty years! One example, engine number 105, originally built in 1886 as a Camelback with a Wootten firebox, and rebuilt with a standard design boiler in 1894, was not retired until July of 1951, having performed for 66 years! Based upon their size, and the number of years in which they operated, it would not be an understatement if one said these locomotives more than paid for themselves many times over.

The Great Depression years took its toll on re-shopping many locomotives, especially those in need of heavy repairs such as firebox or boiler replacements. During a five year period (1936-1941) no less than 45 Consolidations were scrapped. A motive power shortage during World War II kept most of them from being scrapped, but the post war years changed that considerably. Diesels had arrived taking over many yard duties as well as some branch line service. A drop in business after the war allowed the UP to retire 126 Consolidations in 1946 and 1947. An additional 37 were scrapped in 1948 and 1949. And, of course, during subsequent years one by one the total locomotives on the roster continued to decline in numbers as more diesels were purchased. During the 1950s several were placed on display in various communities as a relic of the steam era, with this wheel arrangement out-numbering any other that were preserved. The last 2-8-0 to be scrapped was OSL number 6537 (formerly 537, renumbered to make room for a diesel in the 500-series) at Denver on December 29, 1958. The remaining locomotives of this type (on the roster as of 1959) were subsequently donated to various communities along the UP.

In the mid-1920s the UP adopted new paint standards, resulting in larger six inch (replacing three inch) "Union Pacific" name painted on the cab sides, along with a colorful shield attached to the tenders. The shields vanished during the depression era. Large numbers were displayed on the tenders until 1937. The original numerals in the 1937 scheme provided a narrower (on cabs) width number, which was changed to a wider (final) style by 1939. In the 1937 standards the name "Union Pacific" was spelled out on the tenders. Additional modifications, such as replacement of the round number plates on the boiler fronts, and changing the placement of the headlight onto a cast shelf with a square number plate, were among the major changes.

The first Mikado (2-8-2) wheel arrangement came to the OR&N in July of 1910. The first locomotives of this wheel arrangement were built for the Japanese Government Railways by Baldwin in 1897, from which the type derives its name. The Union Pacific changed the name from Mikado and adopted the name MacArthur (the commanding General in the Pacific during World War II), because of our conflict with Japan. Attempts to change the name by other railroads were made with only a little success. The UP and affiliated lines purchased hundreds of Mikado-type locomotives between 1911 and 1921. The early locomotives were provided with the Harriman Common Standard 57-inch drivers. All later versions had 63-inch drivers and were suitable for both freight and passenger service. Locomotives of this class remained supreme until the arrival of heavier power (2-10-2s and 2-8-8-0s) starting in 1917. Into the 1940-era many worked on main line runs where moderate gradients existed. Many were used in yards where heavy switching service was a requirement, and continued to work regularly on main line local freight assignments (and some branch lines where heavier rail and traffic volumes existed) until replaced by diesel locomotives in the mid-1950s.

This class survived the Great Depression, and none of them were scrapped until after World War II due to an acute motive power shortage at that time. A drop in business after the war, along with the purchase of additional diesels assigned to the western lines, allowed the UP to retire 87 MacArthur's in 1946 and 1947. An additional 49 were scrapped in 1948 and 1949. In subsequent years, one by one, the total number of steam locomotives on the roster continued to decline as more diesels were purchased. The last 2-8-2 to be scrapped was UP number 2272 at Cheyenne on July 30, 1958. Four of them survived and have been preserved and donated for display in various communities (the 2564 was later relocated to the Orange Empire Railway Museum at Perris, CA.) along the UP.

The Two-Ten-Two (TTT class designation) were never called "Santa Fe" type on the Union Pacific Railroad. This class was a popular main line freight engine and operated nearly forty years on various segments of the system until replaced by diesels. Even after larger power had displaced these locomotives, they continued operating on local freights, as helpers, or in general work train service. One powerful 2-10-2 could replace nearly two 2-8-0s. Many were equipped with snowplow pilots since the class was considered to be extremely dependable during winter snow season. In fact, several were held in reserve for this purpose until the end. This class locomotive (the first fifteen) arrived with 10,000 gallon tenders. During the early years many were equipped with 18,000 gallon tenders for main line operation. Later these tenders were removed and traded with the 2-8-8-0 class, and the 12,000 or the 13,500 gallon tenders were the most common type used. However, some were equipped with former Chesapeake & Ohio 21,000 gallon tenders to eliminate the need for frequent water stops on the Denver to North Platte territory. Fuel oil capacities indicated in various records do not appear to be accurate or consistent based upon the size of oil bunkers displayed by certain photographs contained within this volume. Hardly any two records (railroad or railfan rosters prepared by other sources) agree in their entirety.

Tests with 2-10-2 Locomotive on the Union Pacific

Breaking Up Trains and Use of Helper Engines Eliminated; Results Show High Sustained Capacity

The Union Pacific System has recently reduced the grades on certain parts of the Western Division. With a view to increasing the train load on the reconstructed 'line, locomotives of the 2-10-2 type were designed for this division under the supervision of C. E. Fuller, superintendent of motive power and machinery and A. H. Fetters, mechanical engineer. Twenty-seven of these engines were built last year by the Baldwin Locomotive Works, fifteen for the Union Pacific, six for the Los Angeles and Salt Lake and six for the Utah Railway. Of these, ten were placed in service on the Union Pacific between Ogden, Utah, and Evanston, Wyo., a division 75.8 miles long. The old line between these points had ruling grades of 93 feet per mile eastbound, while the new line has a ruling grade of 60 feet per mile. East of Evanston for 400 miles the ruling grade is 43 feet per mile. The 2-10-2 type locomotives were designed primarily to move the same tonnage eastbound over the new line with a ruling grade of 1.14 per cent, compensated for curvature, that the Mikado locomotives handle over the lines with .83 per cent grades. A secondary object was the elimination of helper service on this district, which has several difficult grades.

These locomotives have been in service for six months and have given very satisfactory results. A condensed profile of the line on which they are operating is shown below. The reconstruction work has not been completed on this line and there are short sections where the grade is still 63 feet per mile, uncompensated for curvature. In tests the 2-10-2 type locomotives handled 1,800 tons eastbound over this division at an average running speed of 15 m. p. h. The average coal consumption was 358.4 lb. per thousand gross ton miles. The curves reproduced herewith show the tractive effort and drawbar pull developed and also the horse power. A maximum of 2,940 horsepower was developed at a speed of 30 m. p. h. This is at the rate of one horsepower for every 121.6 lb. weight of the locomotive in working order, which is unusually good performance.

The Union Pacific 2-10-2 type locomotives have a rated tractive effort of 70,450 lb. with 285,500 lb. on the driving wheels, the ratio of adhesion being 4.05. The total equivalent heating surface is 7,045 sq. ft. or one sq. ft. for each 10 lb. of tractive effort. This ratio indicates ample steaming capacity for the heavy class of freight service in which these engines are used.

[photo caption] Heavy Freight Locomotive for the Union Pacific Which Develops 2950 Horsepower

The boiler is of the straight-top type with a wide, deep firebox placed back of the drivers and over the rear truck. A combustion chamber four feet long extends forward into the boiler barrel, and the tubes have a length of 22 ft. The middle barrel ring has a slope on the bottom to provide a sufficiently deep water space under the combustion chamber. All seams in the firebox and combustion chamber are welded, with the exception of that uniting the back sheet with the crown sheet and side sheets. The seam around the fire-door opening is also welded. Flexible stay-bolts are used in the breaking zone and in the six front rows of stays over the combustion chamber. At the point where the three upper rows of flexible stays on each side pass through the boiler barrel, bosses are welded to the sheet in order to provide a sufficient number of threads for the staybolt sleeves. Both the coal burning and oil burning locomotives are equipped with Security .sectional arches and the coal burners arc, fired by Street type "C" stokers. The superheater consists of 45 elements and has a superheating surface of 1,262 sq. ft.

The piston valves are 15 in. in diameter and are driven by Walschaert valve gear which is controlled by a Ragonnet power reverse gear having both air and steam connections. The piston heads are steel castings of dished section 7 in. wide with phosphor bronze bearing rings and gun iron packing rings. The piston rods are of open-hearth steel heat treated and hollow-bored. The same material is used for the crank pins and driving and trailing axles which are also hollow-bored. Long driving boxes are applied to the main axle and lateral motion boxes to the front axle. The latter are used in connection with the Economy constant resistance leading truck.

The frames are annealed vanadium steel castings 572 in. wide and spaced 42 in. between centers. They are braced transversely between adjacent driving wheels and also at the third, fourth and fifth pairs of driving pedestals. The driving box wedges are self-adjusting. The Commonwealth rear frame cradle is applied in combination with the Delta .trailing truck, which serves the triple purpose of a frame, radius bar and equalizer. The trailing truck is equalized with the two rear pairs of drivers, the equalization being through a central vertical, heart-shaped link which is suspended from a transverse beam hung from the rear driving springs. This link acts not only as the equalizer connection, but also as the rear truck radius bar pin. It is circular in section at its lower end, and is guided in the frame cradle casting. The bearing between the equalizer frame of the truck and the locomotive frame is made with a spherical surface to provide sufficient flexibility.

The driving brake system is divided between the third and fourth pairs of wheels. The rear cylinders are placed in a horizontal position back of the main pair of wheels, while the front cylinders are placed vertically and are bolted to the cylinder saddle casting. The arrangement is such that all shoes bear on the backs of their respective wheels. The tender is carried on forged steel wheels, and is of the Vanderbilt type, with equalized trucks and a one-piece cast steel frame.

Excessive wear in the early Gresley valve gear components allowed increased duration of the center cylinder admission cycle on the extend stroke. This was an undesirable defect because it created extreme stress on the center main rod bearing-brass and crank.

Late in 1934, following destruction of the Gresley valve gear in a collision accident, 9014 was modified with application of a third set of Walschaert valve gear to operate the center cylinder valve. All valve gear setting was then made with a modified ALCO Type 'E' power reverse. These changes were planned for all fifteen in the 9000-9014 series, but only eight were completed.

Extended valve stems were removed and solid front valve heads applied. Air pumps on the altered locomotives were moved to each side of the boiler, leaving the smoke box front bare, thus the nickname 'Baldface.'

The UP acquired the first fifteen 2-8-8-0 compound mallets, built in 1918, for service on the Wyoming Division mountain grades, plus one for the OSL. Their success resulted in fifty-four additional locomotives purchased between 1920 and 1924 for service where heavy grades existed on the UP, OSL and OWR&N lines. These articulated locomotives arrived with 12,000-gallon tenders and many were replaced with 18,000-gallon six-axle truck tenders. Only a few received the modified 13,500-gallon tenders, which was basically a large square box added on top of 12,000-gallon tender. By the mid-1930's, converting the compounds to simple articulated design was part of an upgrading program to allow greater speeds at the cost of slightly less tractive effort. In 1937 (and thereafter) locomotives converted then became 3500-series numbers. The last were converted and re-numbered in 1944.