PROTOTYPE SPECIFIC INFORMATION

Union Pacific wanted something that could make the same speeds as the Challengers but could carry the entire 4,290-ton train over the Wasatch Mountains without a helper. The easiest solution was to scale up the successful Challenger design by adding another pair of drivers to each half of the locomotive, thus making a 4-8-8-4.

In 1941, UP placed an order for 20 4-8-8-4’s, numbered 4000 through 4019, with the American Locomotive Works. According to legend, an unidentified machinist at the ALCO plant is responsible for the name “Big Boy”, having scrawled the name in chalk on a partially completed locomotive.

The Big Boys were exactly what the railroad wanted. They were coal burners with 68-inch drivers, 135,375 pounds of tractive effort and 6,000 horsepower. They started service on the line from Ogden to Green River, Wyoming and their operating range soon increased to cover the line all the way to Cheyenne.

Traffic during WWII resulted in five more Big Boys, numbered 4020 through 4024, being built in 1944. These versions were slightly heavier than the original order due to wartime materials restrictions. Despite the influx of diesel locomotives following WWII, the Big Boys and Challengers remained the prime power on the Overland Route. They also say service as helpers, leading gas turbines and diesels over Sherman Hill. They remained active through the 1950s and weren’t retired until the early 1960s. By then, the first 20 units had been run well over one million miles.

4-8-8-4 LOCOMOTIVE FEATURES:

• Illuminated number boards and headlights
• Headlight turns off in reverse
• Illuminated directional back-up light in the tender
• Correctly operating eccentric cranks
• Adjustable top cab vent and cab windows
• Pivoting front and rear engines for negotiating 22” radius curves
• Current pick-up on all driver and wheels
• Boiler backhead with full details and printed gauges
• Synchronized chuff, whistle, bell, blow-down, air compressor, dyno and pop-off valve sounds
• User-controlled whistle, short whistle, bell, squeal, coupler crash, injector, water stop and light dimmer
• Individually-applied detail parts, including brass-painted bell and whistle, piping, valves, generator, steps, air pump, air tanks, reverser and coupler lift bar
• Front coupler pocket can be inserted to mount operating coupler
• Dual speakers for great sound quality
• Upgraded headlight lighting with brighter LED
• Improved loco-to-tender connection harness for increased durability and serviceability
• Minimum recommended radius: 22”

LOCOMOTIVE SOUND-EQUIPPED MODELS ALSO FEATURE

• On-board DCC decoder with SoundTraxx Tsunami2 sound
• Dual speakers for optimal sound quality
• Sound units operate in both DC and DCC
• Full DCC functions available when operated in DCC mode
• Engine, whistle, and bell sounds work in DC
• All functions NMRA compatible in DCC mode
• Precision slow speed control
• Program a multiple unit (MU) lashup with lead unit only horn, bell, and lights
• Many functions can be altered via Configuration Value (CV) changes
• CV chart included in the box

PRIMED FOR GRIME MODELS FEATURE

• Duplicated look and feel of “In Service” equipment
• Faded base colors matched to the prototype
• Perfect starting point for adding grime and rust

LEGENDARY LIVERIES

What are Legendary Liveries? An Athearn exclusive, they are the ultimate answer to “What if?” Featuring some of the most popular railroad paint schemes of all time, these models are perfect for collecting, protofreelancing, or just plain fun! Whether company proposed paint schemes, canceled locomotive orders, or alternate takes on history, Legendary Liveries are fun and unique additions to any roster. Enjoy these items, and answer the ultimate railroad question of: “What if?”

Union Pacific

4-8-8-4 locomotives were owned exclusively by the Union Pacific. Rumored to be named the “Wasatch” class, they acquired the name “Big Boy” after an ALCO factory worked scrawled the text on the first unit’s smokebox during construction. They ran from 1941 to 1959.

ROAD NUMBER SPECIFIC FEATURES:

• #4000 As-delivered, coal burners, cooling pipes
• #4003 Primed For Grime finish to represent in-service look, coal burner, cooling pipes
• #4019 Smoke lifters, coal burner, cooling pipes
• #4020 As-delivered, coal burners, cooling pipes
• #4024 Legendary Liveries Greyhound scheme with yellow trim, smoke lifters, oil burner, no cooling pipes

Looking for more Athearn 4-8-8-4 Big Boy Steam Locomotives? Click here!