Union Pacific 4-8-8-4 "Big Boy" Locomotives in the USA

During the late 1930s, the Union Pacific often used helpers to move trains from Ogden to Wahsatch. The UP wanted to simplify this move so they asked their "Department of Research and Mechanical Standards" (DoRMS) to design a locomotive that could pull a 3600 ton train unassisted over the 1.14% grade of the Wahsatch.

The designers determined that to pull a 3600 ton train, a tractive effort of 135,000 lbs would be needed. Assuming a factor of adhesion of 4.0, the weight on drivers would have to be 4.0 * 135,000 = 540,000 lbs. Given an axle loading of 67,500 lbs each, this would require 8 drivers or an x-8-8-x wheel arrangement. The designers agreed upon the 4-8-8-4 design. Next, the horsepower and cylinder sizes were computed based on 300 psi boiler pressure. Although they weren't planning to pull these freight trains at 80 MPH, the DoRMS designed them for 80 MPH in order to have a sufficient factor of safety built into the design. What resulted is considered by many to be the most successful articulated steam locomotive ever built. Number 4000 was delivered to Omaha at 6PM, September 5, 1941.

The 25 Big Boys were built in two groups. The first group of 20 locomotives, called "Class 1", were built starting in 1941. They were numbered 4000-4019. The second group of 5 locomotives, "Class 2", were built in 1944. They were numbered 4020-4024.

The last revenue freight pulled by a Big Boy was in July of 1959. Most were retired in 1961. The last one was retired in July of 1962. As late as September, 1962, there were still four operational Big Boys at Green River, WY.

The total mileage of each of the Big Boys from class 1 were roughly the same - 1,000,000 miles. 4016 had the lowest mileage -- 1,016,124. 4006 had the highest mileage - 1,064,625. Of the second group, 4024 had the highest mileage - 811,956.


Big Boy Facts and Trivia

A Big Boy is Not a Mallet

Periodically, I hear the Big Boy referred to as a "Mallet". Technically, this is not true. Anatole Mallet designed his steam locomotive that 1) was articulated, and 2) used compound expansion (high and low pressure cylinders). The Big Boys, as well as many other articulated steam locomotives, used simple expansion (the same pressure in all four cylinders), and thus, are not true mallets.

What do those cab markings mean?

Big Boy Cab Markings UP: Union Pacific
4002: Locomotive number
4-8-8-4: Wheel arrangement

NOTE: Some used "4-8-8-4 1" and "4-8-8-4 2" to distinguish between the first and second classes of Big Boys.

68: 68 inch drivers
23 3/4 - 23 3/4: Cylinder diameters (front and rear)
32: Piston stroke
540: 540,000 pounds of weight on drivers
MB: MB type stoker

What is the Sharpest Curve a Big Boy can Negotiate?

The sharpest curve the Big Boys could negotiate was a 20 degree curve. In HO scale, this would be a 40 inch radius curve.

How Much Coal and Water Did They Use?

According to William Kratville's "Big Boy" (page 25, 2nd paragraph), at maximum firing, the usual four hour trip uphill would cosume 20 tons of coal and 12,000-13,000 gallons of water. This equates to:

Usage Per 4 HoursUsage Per HourHours Per Full TenderMiles Per Full Tender (at 25 mph)
Coal:20 tons5 tons5.6140
Water:12,500 gallons3125 gallons8200

As you can see, coal was the limiting factor for the Big Boys. When working hard, a Big Boy could theoretically operation for over 5 hours and travel up to 140 miles. However, few enginemen would operate on low fuel (or water). It would have been common to refuel and take on water every couple hours or when convenient.

Approximate Timeline of the Last Years of Big Boy Operations

Will a Big Boy Ever be Restored to Operating Condition?

Over the years, this question came up frequently. Many used to laugh at the question because it seemed so ridiculous. However, when the news of the proposed restoration of 4018 in Dallas for a movie was announced back in 1998, many hoped it could come true. As it turned out, the news about restoring 4018 was only a proposal in its infancy and nothing ever materialized of it.

If one was to restore a Big Boy it would seem to make sense to start with the Big Boy that is in the best condition. At one time, this would have been 4023, currently at Kenefick Park, Omaha, NE. During the end of their careers both Challenger 3985 and Big Boy 4023 were rebuilt and placed in the Cheyenne UP roundhouse. However, 4023 was later placed on display in Omaha and the weather and environment has taken its toll on 4023. 4014, the Big Boy displayed for a long time in Pomona, CA had been kept in immaculate condition by the Southern California Chapter of the Railway & Locomotive Historical Society. Of all of the Big Boys that I had seen, 4014 looked to be in the best shape. I had thought that this would be the best restorationi candidate if a restoration were to ever happen.

According to many sources, the UP was never interested in running a coal-fired locomotive on their road any longer (the 3985 (4-6-6-4) was converted to oil in the late 1980's). Naturally, the next question one asks is "why not convert a Big Boy to burn oil?". This had been tried back in the 1940s or 1950s on 4005 with a single burner, without success. It had been said that it is not feasible to fire a Big Boy with oil due to the nature of the firebox (which was designed for burning semi-bituminous coal from southern Wyoming) and boiler capacity. However, 3985 was converted to burn oil and its firebox is not all that different from that of the Big Boy's.

Steve Lee (head of UP's steam program) had also stated that it wouldn't make much sense for UP to restore a Big Boy, as there were only two places on the entire system that are large enough to turn a Big Boy, and those places are only a few miles apart. However, the Challenger was often turned using wyes which could also, almost certainly, handle a Big Boy.

4014 Restoration

In December of 2012 discussion about the possibility of restoring a Big Boy to operating condition emerged. At that time many people who heard about this were hopeful but those who have heard of plans like this come and go before were skeptical. From December 2012 to July 2013 very little, if any, new information was available. Then, on July 23, 2013 the announcement was made that ownership of 4014 was to be transferred from the Southern California Chapter - Railway & Locomotive Historical Society to the Union Pacific for the purpose of fully restoring the locomotive to operating condition!

More Information

Class Details by Steve Llanso of Sweat House Media

Class Big Boy (4884-1) (Locobase 346)

Data from tables and diagrams in 1947 Locomotive Cyclopedia and UP 11 - 1946 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Many thanks to Kenneth Mileski for his 11 May 2016 email suggesting that Locobase's entry include information on 4014's restoration.) Works numbers were 69571-69575 in September 1941, 69576-69581 in October, 69582-69583 in November, 69584-69587 in December, 69588-69590 in January 1942.

Union Pacific senior manager of Heritage Operations Ed Dickens Jr. said in 2016 that the 4-8-8-4 series originally was to have been called (Wasatchö. After a never-identified UP worker wrote "Big Boy" on one of the cylinders, that nickname stuck.

Firebox heating surface included 111 sq ft (10.3 sq m) in seven inverted-T shape circulators and a combustion chamber extending 9 ft 3 in (2.8 m) forward of the ashpan. One of the heaviest engines in the world, the 25 "Big Boys" were the largest steam engines ever built for regular service. The last five delivered in 1944 were fitted with Type A superheaters; see Locobase 13026 for an analysis of why the change was made.

The Big Boys carried almost 70,000 lb (31,752 kg) more on its relatively tall drivers than did any other engine of comparable driver size. (The DM&IR's M3 2-8-8-4 engines -- Locobase 2405 -- had a higher weight on drivers, but had 63-inch/1,600 mm drivers.) Each one cost $265,000 when delivered.

These engines could maintain 70 mph (113 km/h) and rode quite steadily; see Locobase 338 for a description of the revised bearing design that permitted smooth riding at such speeds.. (The four pistons evacuated 22,700 cu ft/642.8 cu m of steam per minute at that speed.) On the other hand, Farrington (1976) claims they were hard to fire and thought a feedwater heater should have been preferred to the exhaust steam injector they carried.

Over a ruling grade of 1.14% the 4-8-8-4s could move 4,000 tons (3,636 tonnes) of freight at 20-25 mph (32-40.25 km/h). When the ruling grade between Ogden, Utah and Green River, Wyoming (176 miles/283 km) was reduced to 0.82%, the tonnage rating climbed to 5,360 tons (4,873 tonnes). At 45 mph (72.5 km/h), these engines developed 6,000 drawbar horsepower (4,476 kW). Among their many abilities was the flexibility to move around curves of 20 deg.

Also, the online encyclopedia [] (visited 14 July 2005) notes approvingly: "They did sterling service in the Second World War, especially since they proved so easy to fire that even a novice could do a fair job. Since many men who were unsuited to combat service were instead drafted into railroad service to replace crewmen who joined up, this proved essential."

See the trainorders.com forum thread that began 1/05/13 ([]) when KeyRouteKen commented on a recent documentary: "One of the guys talked about shoveling 27 tons of coal "by hand". Stoker must have been inoperable. Then he said they dropped down one time to 165 lbs of steam so they threw some creosoted pieces of crossties in the firebox to raise steam again. That was funny.

"And the best story was the guy who would open the firebox door and hold his shovel there to make a vent. Great, except when the hogger pulled back on the throttle, and the entire shovel was sucked into the firebox ! (grin!) "

Bob3985 replied:"The fireman who hand fired the Big Boy was Dillard Hill and they indeed had broken the stoker auger and could not auto deliver the coal to the firebox so they set their train out and made a run for the Laramie roundhouse keeping the steam up by hand."

Hotwater added:"... hand firing any locomotive equipped with a stoker, it really isn't THAT big of a deal. Just because the stoker auger doesn't work, does NOT mean that the steam distributing table doesn't function. All that is needed is for one or two men (Fireman & Headend Brakeman) to continuously shovel the coal onto the distributing table, and the steam jets will blow the coal to the necessary portions of the firebox. I speak from experience! It works on any steam locomotive equipped with a stoker."

4005 was converted to oil-firing for trials in 1945. Within a year, she was converted back to coal firing and no other Big Boys were converted. According to Chris Hohl, 4019 was fitted with smoke deflectors for tests in 1944-1945; no other members of the class were converted.

Drawing from William Kratville's book Big Boy, Nick Chillianis posted information about tests conducted 3 April 1943 on the Wasatch grade. Pushed at a rate of 9,980 US gallons (37,434 litres) of water and 9.66 tons (8.8 tonnes) of coal consumed per hour, engine #4016 produced 7,157 hp (5,339 kW) at the cylinders while moving 3,883 tons (3,530 tonnes) of train at 41.1 mph/66 km/h (drawbar hp was 6,290.) Other engines in the test produced 5,800 dbhp (4,327 kW) under similar conditions. See [] (12 Nov 1998, 8:46 AM).

At Ken Mileski's suggestion, Locobase checked up on 4014's restoration to service. In July 2013, the Union Pacific struck an agreement with the Southern California Chapter of the Railway & Locomotive Historical Society in Pomona, Calif to regain ownership of the 4014, which had been on display at the Rail Giants Train Museum since 8 January 1962. According to the UP, 4014 had run 1,031,205 miles in less than 18 years of service before its final revenue run on 21 July 1959. (That computes to a daily average of 160 miles for every calendar day.)

In exchange, UP transferred title of UP 6-axle diesel SD-40-2 #3105, a boxcar, and a caboose.

After months of careful assessment and preparation, four UP diesels moved the 4014 onto the national rail network on 26 January 2014. Ten freight cars provided additional braking power. Its first stop was Colton, CA, where it remained until its 1,300 mile (2,093 km) journey to Cheyenne, WY. That trip ended on 8 May 2014 with the 4014's safe arrival.

An initial estimate of 3-5 years for the restoration was later revised to 5-7 in part because the steam shop at Cheyenne had to be substantially modified to accommodate 4014. In addition, many systems, such as the entire front engine, were removed to allow better access during their reconstruction. One significant change will be the conversion to oil fuel (#5 fuel oil) from coal burning.

At just under 350 tons (316.3 tonnes), the 4014 is the largest wheeled restoration project ever undertaken.


Class Big Boy (4884-2) (Locobase 13026)

Data from UP 11 - 1946 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 72777-72781 in November 1944.

Locobase 346 describes the first twenty of these Big Boys. This later quintet is usually described as reflecting the wartime limitations of certain metals, which required the builder to substitute heavier steel components. Even so, their engine weights were still lower than the maximum weights believed to have afflicted the C & O's 2-6-6-6 H-6 Allegheny class (Locobase 304). Firebox heating surface included 111 sq ft (10.3 sq m) in seven inverted-T shape circulators and a combustion chamber extending 9 ft 3 in (2.8 m) forward of the ashpan.

What is not usually mentioned is the change in boiler heating surface area and the substitution of a Type A superheater for the earlier group's Type E. John E. Rimmasch of

Wasatch Railroad Contractors contributed to a Trainorders forum discussion with comments that shed light on the reason for the change ([]):

On May 25, 2011, Rimmasch lays out the conditions that most likely dictated the change: "On the UP between 1941 and the end of steam, it was not uncommon to see super power get new tubes annually or even every six months. This was due in large to a number of conditions. A.) The water in Utah and Wyoming was hard enough that the flue bundle would clog up and tubes would burn quickly. B.) The UP Super Power was high pressure steam, which means we had a lot more heat. 800's, 300 psi, Big Boy's 300 psi and Challengers 280 psi. C.) The length of the tubes in the 800s, 3900s and 4000 was nearly the maximum allowable tube length for any locomotive (respectively 20-22 feet [6.1-6.7 m] long). It was found that when tube lengths near or surpass 18 feet long [5.5 m] , they had more of a tendency to bounce and tear apart. The stretching effect on these long tubes precluded many of them from being re-used.

"In the case of the UP, when you combine all three symptoms above, you end up having to change tubes more often ... [R]ather than lose a locomotive on tube failure, the UP (and other lines) found it cheaper and better to simply change them more frequently. ...A Big Boy could get new tubes in less than 36 hours."

In a later post, Rimmasch argues that Alco used a Type E superheater, which was harder to maintain because of its more complex steam path, to cover its bets: "I assume that the Big Boy originally had type E's with an increased heating surface area as ALCO was unsure if they had produced enough heating surface area to support the bore and stroke (multiplied by 4) and, after delivery quickly found that they had enough steaming capacity that the locomotive did not require type E's and was therefore reduced to type A's."

Rimmasch implies that the change to Type A superheaters came during the production of the first twenty locomotives, but the 1946 diagrams show only that the 4884-1s had Type E and the 4884-2s had Type As.

Like the earlier batch, these engines served the UP into the 1960s before all of them were retired in 1962--4021 in January, 4022 in February, and 4020, 4023-4024 in July.

Principal Dimensions by Steve Llanso of Sweat House Media
ClassBig Boy (4884-1)Big Boy (4884-2)
Locobase ID346 13,026
RailroadUnion Pacific (UP)Union Pacific (UP)
CountryUSAUSA
Whyte4-8-8-44-8-8-4
Number in Class205
Road Numbers4000-40194020-4024
GaugeStdStd
Number Built205
BuilderAlco-SchenectadyAlco-Schenectady
Year19411944
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)18.75 / 5.7118.75 / 5.71
Engine Wheelbase (ft / m)72.45 / 22.0872.46 / 22.09
Ratio of driving wheelbase to overall engine wheebase 0.26 0.26
Overall Wheelbase (engine & tender) (ft / m)117.58 / 35.84117.58 / 35.84
Axle Loading (Maximum Weight per Axle) (lbs / kg)67,800 / 30,75467,800 / 30,754
Weight on Drivers (lbs / kg)540,000 / 244,940545,200 / 247,299
Engine Weight (lbs / kg)762,000 / 345,638772,250 / 350,287
Tender Loaded Weight (lbs / kg)427,500 / 193,911436,500 / 197,993
Total Engine and Tender Weight (lbs / kg)1,189,500 / 539,5491,208,750 / 548,280
Tender Water Capacity (gals / ML)24,000 / 90.9125,000 / 94.70
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)28 / 25.5028 / 25.50
Minimum weight of rail (calculated) (lb/yd / kg/m)113 / 56.50114 / 57
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)68 / 172768 / 1727
Boiler Pressure (psi / kPa)300 / 20.70300 / 20.70
High Pressure Cylinders (dia x stroke) (in / mm)23.75" x 32" / 603x813 (4)23.75" x 32" / 603x813 (4)
Tractive Effort (lbs / kg)135,375 / 61405.14135,375 / 61405.14
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.99 4.03
Heating Ability
Firebox Area (sq ft / m2)704 / 65.43720 / 66.91
Grate Area (sq ft / m2)150.30 / 13.97150 / 13.94
Evaporative Heating Surface (sq ft / m2)5889 / 547.305755 / 534.85
Superheating Surface (sq ft / m2)2466 / 229.182043 / 189.87
Combined Heating Surface (sq ft / m2)8355 / 776.487798 / 724.72
Evaporative Heating Surface/Cylinder Volume179.46175.37
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation45,09045,000
Same as above plus superheater percentage58,61756,700
Same as above but substitute firebox area for grate area274,560272,160
Power L132,74328,743
Power MT1069.42929.82

Surviving Big Boy Photos


UP 4004 in Cheyenne, WY. 6/27/1992 photo by Wes Barris

4004: Holliday Park, Cheyenne, WY

Cheyenne is also the home of UP's steam program where a number of locomotives are kept:
A Brief History of 4004
  • In October 1958 4004 ran its last trip.
  • In November 1958 4004 was placed in storage.
  • In February 1962 4004 was officially retired with 1,060,402 miles on it.
  • On June 28, 1963 it was placed on display in HoLliday Park in Cheyenne. A diesel switcher moved 4004 across 600 feet of temporary track into the park. During the move, a truck followed, feeding air into 4004's brake system as a precaution.
  • The Elesco cold water turbine pump and a Nathon water injector were removed from 4004 for use on Challenger 3985.
  • One viewer wrote to me stating that in 1973/74 he thought that there was a Big Boy displayed near the Wyoming/Colorado border along I25. It could not have been 4004 (because 4004 was placed in Holliday Park in 1963) and there were no other Big Boys, or any locomotive for that matter, that would have been displayed in this area. If anyone does know of a locomotive that was once displayed in this area, please let me know.
  • An August 1, 1985 rainstorm caused Holliday Park to flood. Water reached the top of 4004's drivers! [Photo]
  • In 2001 there had been talk about moving 4004 from Holliday Park to the depot about 9 blocks away but it turned out to be only a rumor.
  • In 2005, 4004 received some cosmetic work including a new paint job and lettering and new windows which greatly improved the locomotive's appearance. While the external appearance of 4004 is good, the cab interior, at least used to be a mess. Most of the controls had been removed by either wrench or torch, the firebox door is welded shut, and the seats are either gone or have deteriorated to springs.
Photos and Information

UP 4005 in Denver, CO. 6/23/1992 photo by Wes Barris

4005: Forney Transportation Museum, Denver, CO

A Brief History
  • In 1946, as a test, 4005 was converted to burn oil. This test was undertaken because of a the threat of a coal strike. It operated as an oil-burner for a couple years. In 1948 it was converted back to burning coal. The test results showed that burning oil in a firebox desgned for coal did not produce the required heat.
  • In 1953, 4005 was involved in an accident. A turnout for a siding was left in the wrong position. 4005 passed the turnout at 50 mph causing the engine to derail and land on its left side. Three people were killed. 4005 was repaired in Cheyenne. Scars can still be seen on the left side of the locomotive. Details about the accident are available below.
  • In October 1957 4005 made its final trip.
  • In November 1958 4004 was placed in storage.
  • On July, 1962, 4005 was officially retired with 1,043,624 miles on it.
  • 4005 had been partially dismantled in preparation for shipment to Argentina. However, the recipients in Argentina were unable raise enough money to acquire it. So 4005 stayed in the US.
  • In June 1970 4005 was placed on display at the Forney Museum of Transportation. A torch had to be used to cut off parts of the casting that control the limits of lateral movement of the trailer. These had to be renewed in order for the engine to be able to negotiate curves during moves that came years later.
  • In January 1999, it was temporarily moved next to the Platte River at 15th Street. Later it was moved to 4303 Brighton Blvd. During these moves, to prevent major damage to the cylinders, 4005's main rods were removed prior to the move. Also, a substantial amount of work was required to repair some critical damage to the trailing truck centering devices. The cost of relocating UP 4005, C&NW 444 (a 4-6-0), two 85' passenger cars, a UP derrick and rotary snow plow and a few old, wood passenger cars in various states of disrepair to their temporary location was $600,000. Jack Forney deserves special credit for spending a lot of money and time to preserve and relocate a large amount of historic RR equipment.
  • It finally made it back to a location inside the Forney Transportation Museum in 2001. Despite the recent care and a new paint job, 4005 is probably in fair to poor condition.
Photos and Information

4006: Museum of Transportation, St. Louis, MO

A Brief History
  • 4006 was placed in storage in September 1957.
  • In 1961, 4006 was retired with 1,064,625 miles on it -- the most of any Big Boy.
  • It was donated to the museum in 1961 with the tender of 4003. Before arriving at the museum, 4006 spent a year being cosmetically restored in the Alton & Southern shop in East St. Louis.
  • 4006 was painted in 1995 and is displayed directly ahead of UP Centennial 6944. Stairs provide access to the cab where most controls are identified.

Photos and Information


UP 4012 in Scranton, PA. July 1993 photo by Wes Barris

4012: Steamtown National Historic Site, Scranton, PA

A Brief History
  • In 1962, 4012 was retired with 1,029,507 miles on it.
  • It was donated to Nelson Blount's Steamtown USA just before Steamtown's move to Bellows Falls, VT in late 1964. 4012 departed Cheyenne in August and arrived in North Walpole in September. During the move of 4012 to North Walpole, the tender derailed in Manchester, NY.
  • Mr. Blount later moved his collection of steam locomotives from North Walpole, NH to the new site in Bellows Falls.
  • Steamtown's locomotives were moved to Scranton in 1984, 4012 was displayed for many years in the rear of the Lackawanna Station Hotel in downtown Scranton. The hotel was only 1/2 mile away from the Steamtown yard.
  • In 1993 after bridges between the Hotel and Steamtown were replaced, 4012 was moved into the yard at Steamtown. Contrary to a rumor once posted on rec.railroad, Steamtown never had plans to restore 4012 to working order.
Photos and Information
  • 4012 (1983 photo of 4012 displayed at Steamtown USA in Bellows Falls, VT courtesy Warren Small)
  • 4012 (November 12-17, 1984. Move from Bellows Falls to Scranton. Photo by Denis Connell, for Railpase news magazine)
  • 4012 (November 12-17, 1984. 4012 parked atop the ex-Lackawanna bridge at Nicholson, PA. Photo by Denis Connell, for Railpase news Denis Connell)
  • 4012 (1992 photo of 4012 displayed near the Lackawanna Station Hotel)
  • 4012 (July, 1993 photo of 4012 displayed in the Steamtown yard by Wes Barris)
  • 4012 (Photo courtesy Mitch Goldman)
  • Steamtown National Historic Site


UP 4014 in Pomona, CA. January 1999 photo by Wes Barris

4014: UP Engine House, Cheyenne, WY (Previously at RailGiants Train Museum, Los Angeles County Fairplex, Pomona, CA)

A Brief History
  • On November 30, 1958 4014 and all other Big Boys were placed in storage.
  • On July 6, 1959 4014 was placed back in service.
  • On July 21, 1959 4014 makes its final run.
  • On December, 1961 4014 is officially retired with 1,031,205 miles on it.
  • The original builder plate was stolen before 4014's move to California. A new, correct one will eventually be made.
  • 4014 was donated to the Southern California Chapter of the Railway & Locomotive Historical Society in January, 1962.
  • In 1989/1990 when the chapter was moving its collection from the original display area behind the horse barns to the new location adjacent to the main parking lot, 4014 gave the movers a surprise. During the move, 4014 moved so easily that it got away from them and ran into the tender of AT&SF Hudson 3450. They left things that way over night while planning on repositioning it the next day. When they arrived the next morning they found 3450 had been pushed partly into the dirt after slowly rolling off the end of the temporary track sections they used for the move.
  • 1997: Of all the Big Boys I had seen, 4014 appeared to be in the best condition. The cab interior gave the impression that all it needed was coal and a fire and it would come to life. When I visited in the mid 90s one of her pistons was removed undergoing some restoration and maintenance work. This confirmed that she was being taken care of very well.
  • A 2001 report indicated that 4014 almost looked like new. Her paint was in excellent condition and one could smell the lubricants used to maintain her. Her smokebox wasn't just painted. It appeared to have the oil/graphite type of finish typical of "live" steam locomotives. She had been given green marker lights in the front and red ones to the side. Her cab needed some painting but otherwise appeared to be in operable condition. There were plans to repair her whistle and hook it up to an air compressor so visitors could blow it.

    A later report stated that the boiler jacketing had been removed to prevent moisture entrapment. She had been painted recently. Her state of preservation included libricated bearings.

  • 4014 was the star in a soda pop commercial where her firebox was lined with foil and soda cans and lit up. Her firebox had also been stuffed with other non-fuel items, namely: school children. The curator stuffed 32 of them in there!
  • 4014 had been maintained by two gentlemen who obviously loved her. I have been told that they had the bell and whistle working on 150 psi of air.
  • A 2010 report mentioned that the boiler is again in need of paint.
  • In 2012 everyone was astonished when a Trains article detailed restoration plans for this Big Boy.
  • In 2019 4014 comes back to life?
Photos and Information


UP 4017 in Green Bay, WI. 10/25/1996 photo by Wes Barris

4017: National Railroad Museum, Green Bay, WI

A Brief History
  • By November 30, 1958, 4017 and all other Big Boys were retired and stored in a "dead line".
  • July 7, 1959, 4017 is returned to steam.
  • July 20, 1959, 4017 makes it final run and again is placed in storage and held in case a sudden traffic surge requires its use.
  • May, 1961, 4017 is officially retired with 1,052,072 miles on it.
  • The National Railroad Museum acquires 4017. Its move from Cheyenne to Green Bay was assisted by both the Milwaukee Road and the Chicago and Northwestern.
  • In 1995 4017 was sand blasted and repainted. The firebox was electrically lighted and viewable by the public.
  • In the summer of 2000 the museum began construction of a new "display hall" to provide shelter the 4017 and other locomotives. 4017 was completely repainted including a color match to reproduce the effect of the waste oil/graphite mix used to paint the Big Boy's fire and smoke boxes during normal operation.
  • By 2002 4017 had been moved into this new display hall. Visitors can enter both the cab and tender.
  • 4017 is one of the better and more complete Big Boys. 4017 was never displayed in a park where vandals could steal or destroy her.
Photos and Information


Robert Willis, collection of Museum of the American Railroad

4018: Museum of the American Railroad, Frisco, TX

A Brief History
  • April 1957, 4018 is shopped in Cheyenne and ran in September.
  • October 1957, 4018 is stored in Green River and will no longer run.
  • July 1962, 4018 is officially retired with 1,037,123 miles on it.
  • In 1964 4018 arrives at the Age of Steam Museum in Dallas and is put on display.
  • In April, 1998 it was announced that 4018 will be restored to operating condition for use in a movie titled Big Boy. During my visit to the Age of Steam Railroad Museum (as it was named back then) in November 2000, I was told that it had been roughly a year since anyone has heard from the person who proposed to use 4018 in a movie. From what I've heard, the cost of restoring this big boy was going to be between $700,000 and $1,000,000. Then, the financing for this proposed movie fell through. As a result, 4018 continued to be displayed at the museum in Dallas.
  • In 2007 4018 was repainted in its original scheme.
  • In 2008 the museum was relocated to Frisco, TX.
Of all the Big Boys I have seen in the 1990s, from the outside, 4018 appeared to be in the worst condition. The main reason I say this is because when I saw it, I noticed that the piston rods had been severed by a cutting torch (see photo). This was done when 4018 was moved to the museum in Dallas back in 1964. Evidently, 4018 was being moved from some undisclosed location on a UP line to the museum when the pistons seized. Pressure from the the UP resulted in the cutting of the rods to get 4018 moving again. Also, the boiler jacketing and much of the piping looked to be in pretty rough shape. I saw moss growing through holes in the boiler jacketing which implied that a substantial amount of moisture was trapped against the boiler (see photo). However, the fire tubes and firebox are apparently in relatively good shape and most (if not all) of the appliances inside of the cab are intact (see photo). Because of how 4018 was parked (between two other locomotives) it was difficult to get a good photograph of her.

Today, 4018 has been repainted and cosmetically is looking much better.

Photos and Information

4023: Lauritzen Gardens, Omaha, NE

During the end of their careers (1956, I believe) both Challenger 3985 and Big Boy 4023 were given general overhauls so that they could continue to run for a few more years. In 1957, they were placed in storage in the Cheyenne UP roundhouse. To the left is a rare photo (from Twilight of Steam Locomotives by Ron Ziel) of both 3985 and 4023 taken sometime after they were overhauled, repainted, retired, and stored in the Cheyenne roundhouse. I have been told that it was actually taken in the early 1960s. 3985 and 4023 were kept inside the Cheyenne roundhouse until sometime between 1971 and 1974. After that time, 3985 was placed on display outside the Cheyenne depot, and 4023 was placed on display outside the UP's Omaha shops until they closed sometime in the late 1980s.

4023 was then moved to Kenefick park where it sat for many years next to Centennial DDA40X 6900. The weather and environment had taken its toll on 4023.

In the early 2010s the city of Omaha decided to re-design the riverfront area including the old UP shops, local industries, and Kenefick park into a new convention center. 4023 was to be placed on display at the convention center site after construction was completed. However, a change in the convention center plans no longer include the display of 4023 and the DDA40X. The locomotives had been temporarily moved to the Durham Western Heritage Museum in downtown Omaha. In March of 2005, 4023 was moved to a location near the Lauritzen Gardens. 4023 is in good shape. The paint looks great and all the missing parts (headlight etc.) have been replaced.

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Wes Barris