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Athearn N scale Big Boy

By | April 24, 2008

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Athearn N scale Big Boy on a track.
Athearn N scale Big Boy
Athearn N scale Big Boy
One of the largest locomotives ever built is available as a sound-equipped N scale model. The accurately detailed Athearn Big Boy 4-8-8-4 also has power worthy of its prototype. The N scale locomotive’s drawbar pull is almost double that of the average N scale steamer. Equipped with a Model Rectifier Corp. (MRC) dual-mode Digital Command Control (DCC) sound decoder, the Athearn N scale Big Boy brings user-controlled sound effects to both DCC and DC layouts.
Prototype. The Union Pacific RR and the American Locomotive Co. developed the 4-8-8-4 simple-expansion locomotive to deal with the steady grades on UP’s line between Ogden and Wasatch, Utah. The railroad wanted a locomotive that could haul trains upgrade without a helper, yet still be fast enough keep up with traffic flow. Alco delivered the first 20 of these massive steamers, nos. 4000 to 4019, to the UP in September 1941.

The UP received five more Big Boys, nos. 4020 to 4024, in 1944 to help deal with increased traffic during World War II. These locomotives were nearly identical to the 1941 engines, but they were heavier because of wartime restrictions on certain lightweight metal alloys, and instead of the earlier aftercooler pipes along the pilot steps, they came equipped with Wilson radiators. Most of the earlier Big Boys were eventually converted to this equipment.

Although built late in the steam era, most of these successful locomotives each logged a million miles or more during their careers. The Big Boys made their final regular runs in 1959.

Athearn N scale Big Boy
Athearn N scale Big Boy
Appearance. All dimensions of the Athearn N scale Big Boy match drawings in the Model Railroader Cyclopedia vol. 1: Steam Locomotives (Kalmbach Publishing Co.)

Our sample came decorated as no. 4009. The aluminum-colored lettering is crisp and straight.

The journal covers on the model’s trailing truck are painted silver. The UP began this practice in the 1950s to indicate roller bearings. However, to be consistent with this era, the tender’s journal covers should also be painted silver instead of black.

The overall detail level on this N scale Big Boy is not that far removed from the Athearn HO scale Big Boy. The N scale model’s molded-in detail is sharply defined. The boiler handrails and almost all piping are separately applied.

Correct for the first 20 Big Boys as-built, our sample has aftercooler piping under the pilot handrails.

The pilot has a swing-out coupler pocket. The user-installed operating front knuckle coupler mounts at the correct height per National Model Railroad Association standard S-2.

The Athearn N scale Big Boy is made primarily of plastic and uses some of the same parts as the Athearn N scale Challenger. These parts include the enclosed all-weather cab and the 14-wheel centipede tender.

Unfortunately, like the Challenger, the Athearn Big Boy has a black Phillips head screw inside the front smokestack. It would have been less noticeable if the screwhead was painted graphite to match the smokestack.

Drivetrain and electronics. A can motor with two metal flywheels inside the boiler drives both the front and rear engines through separate worm gears and gearboxes. The rear drivers of the rear engine and the front drivers of the front engine come with rubber traction tires and contribute to the Big Boy’s impressive 2.9 ounce drawbar pull, equivalent to 73 N scale freight cars on straight and level track.

On the prototype locomotive, only the front engine is articulated. On the Athearn Big Boy, the rear engine also swivels. This, along with .05″ of lateral motion in the wheelsets of the centipede tender’s pedestal truck, allow the model to negotiate tight-radius curves.

I ran the model around an 11″- radius oval of Kato Unitrack and through an Atlas code 55 161/4″-radius curve and no. 6 turnout without interruption of sound. The Big Boy looks better rounding 20″ radius or greater curves.

Most of the model’s electronics are inside the tender. A drawbar and wires permanently connect the engine and tender. Although exploded-view diagrams are included, disassembly of the model isn’t recommended.

Speed control. In DC the sounds and lights started at 3 volts. At 8 volts the model crawled at 2.8 scale mph. The Big Boy reached a top speed of 67 scale mph at 12 volts.

I measured the locomotive’s speed in DC using an MRC Tech 4 power pack. Using the included six-button remote controller provides smoother speed control in DC. First I set the power pack to 12 volts, then I adjusted the model’s speed and direction with the controller.

In DCC the Athearn Big Boy performed best when I used a 12-volt power supply. Under 128 speed steps the model moved steadily at 3 scale mph and accelerated smoothly to a top speed of 68 scale mph.

Since most DCC systems deliver 14 to 18 volts to the track, I also tested the model with our shop’s 16-volt power supply. At this voltage, the transitions between the speed steps was more abrupt, and the model had a faster starting speed. If you have a higher voltage DCC system, I’d recommend using an MRC Universal Voltage Reducer.

Dual-mode sounds. The MRC sound system in the Big Boy is comparable to the one in Athearn’s N scale Challenger. The overall sound quality is good. The speaker in the tender is well-enclosed, so there aren’t any buzzes or rattles.

The engine produces four chuffs per wheel revolution, synchronized to each engine.

The default whistle is the correct steamboat type, but I found this feature to be the weakest of all the sound effects. The whistle has an artificial-sounding echo effect.

With the six-button remote controller I triggered the bell and whistle and programmed some sound effects in DC, including changing the whistle type.

When using DCC, the sound system supports 28 functions. Most of the electronic features are programmable. The instruction manual includes a configuration variable (CV) table.

Using an MRC Prodigy Advance system, I changed the locomotive’s long address to its road number, adjusted acceleration and deceleration, and adjusted the bell volume. I then programmed CV125 with a value of 0 to set all the CV’s back to their factory defaults.

User-controllable sound and powerful pulling capabilities make this new N scale locomotive fun to operate. If you’re an N scaler who has a layout with broad curves and you’re a fan of big UP steam, you should make room in your roundhouse for the new Athearn Big Boy.

Athearn N scale Big Boy
Price: $424.98

Athearn Inc.
1550 Glenn Curtiss St.
Carson, CA 90746

Description: ready-to-run plastic steam locomotive

Road name: Union Pacific nos. 4001, 4006, 4009, 4019, 4020, 4024, and undecorated

N scal Big Boy features
Blackened metal side rods
Drawbar pull: 2.9 ounces
Dual-mode Digital Command Control (DCC) sound decoder
Electrical pickup on 12 drivers and eight tender wheels (in gauge)
Five-pole skew-wound motor with dual flywheels
Micro-Trains operating knuckle coupler on rear of tender(at correct height)
Minimum radius: 11″ (15″ radius or larger recommended)
Weight: 8 ounces (engine and tender)

25 thoughts on “Athearn N scale Big Boy

  1. An excellent review of an excellent model. I appreciate the overview of the prototype as well as the review of the model.

    I would like to own a Big Boy but with 9 & 1/2 inch radius curves and some not real even, I think I need to stay with small locos and short wagons. I rarely run four axle (bogie) wagons the short ones look so much better.

  2. I purchase one of these locomotives to go along with the two Athearn Challenger locomotives I already owned. I found the sound system (especially the whistle) in the Big Boy to be more true to life than that of its sister Challenger's. This locomotive pulls extremely well on the 2% grades on my layout and looks very impressive with a string of 40' reefers in tow. Anyone who is a fan of big steam will get great pleasure from owning and operating this impressive locomotive.

  3. I love this steam-engine, just like MR says it is finely detailed and has crisp printing.
    The BigBoy looks and runs great!!
    The sounds are great although they are the same as the challenger's, but fortunatly there are several whistle types and plenty of sounds only the "all aboard" is a little out of place.
    The only drawback (for me although) is that I cannot program it's CV's due to a to weak dcc set, people with a stronger and/or newer set will probable have no problem at all.
    And there are booster in the market that should solve this problem they say

  4. I spent over 30 years away from the hobby, and after a year of retirement, decieded to return to the hobby. I bought a couple of loco's at a show and my return to the hobby began. At a local hobby shop, I saw the Big Boy, and had to have it. The layout I currently have is 25 x 100 in., so was concerned with possible problems in negoshiating the 12 in rad curves. It does admirably well and will pull all 25 of my cars with ease. It did develop a short, and athaern repaired and sent it back. 30 years ago, I had a Con-Cor Big Boy, and if this one will do 1/2 what it did, then I will be satisified. But boy oh boy, has this hobby changed.

  5. I love my N scale Big Boy built by Athearn. It is the most finely detailed N scale steamer that I have. Only one complaint so far. When following the programming instructions in DC mode, step 10 says to turn the power on, when the power is already on. It should read.." to reset the loco and lock in your programming, turn the power off and then on again. One other point. I have a few pictures of the Big Boy prototypes and the only ones that have after cooler piping under the pilot handrails are 4000, 4001, 4002.

  6. I have one it is a great model epensive though it looks like the real one I have #4001 the only problem is that it needs wide turns or it will derail

  7. Kudos to Athearn for their efforts on the behalf of N scalers. I have purchased two of their Challengers in DGRW livery and I'm very impressed with them. They perform very realistically, lacking smoke and steam, of course, but hey, "we got sound" and power. One of them failed during it's second showing and I'm still holding my breath on factory warranty. Looking forward to my Challenger in spite of this.

  8. Spot on review from Dana! My Athearn Big Boy has certainly impressed me both in looks and performance. I wonder if the default whistle sound is correct for the prototype, as it doesn't sound much like most of the Big Boy videos that I've seen, accepting that some of those have dubbed on sound?

  9. Forty-plus years with MR and your product continues to define excellence. Recently I started an N-scale layout with my grandson, and cannot remember where I saw your formula for proper length-to-weight targets for N-scale rolling stock. Can you remind what back issue to consult ?

  10. Disappointing that no mention was made of the MRC decoders still being used despite the high failure rates of these decoders in the Challengers. My two Challengers have been through 5 decoders so far. Every time I run one of them now I expect the decoder to fail. (Not having any other decoder problems with any other manufacturers). Reluctant to purchase one of these due to the MRC decoders. A non decoder version that would have a connector for another decoder (Tsunami Heavy Steam) would be a nice option with a lower price point.

  11. this is one of the best locomotives I have ever owned, better than the challenger even, I am waiting with baited breath for Athearn to announce the FEFs in N, and maybe if we bug them enough the aux. water tenders.

  12. I am currently freelancing a Union Pacific steam layout. This model from the review looks like the best one for me. Wish I could get one.

  13. I purchased the Challenger N scale for my husband in March of 2009 and in a months time my husband although happy with looks and sounds was having trouble with it. The wheels got out of alinement and then starting running hot. We sent it back to Athearns and it came back a week or so later. It was fine for a few weeks and now the wheels seem to be slipping again which is making us very unhappy.
    Good thing it is warranteed for a year we made need to use it all.

  14. I don't think the screw in the front stack should be an issue. Most folks will paint this out? Since that's the inside of the stack I'd bank that would be more black and grim then not. Even with cleaning.


  15. an unbeleivable N-scale loco, pulls 50 athern coal without a problem, even at 1 on my digitrax dcc.

  16. Bought the Athearns Challenger in 2010 it looks good sounds good but not very reliable had to send it back twice,its a long ways back n forth across the pond,so i do not know if i will chance buying the BigBoy.

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