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Home / News & Reviews / Product Reviews / Staff Reviews / Hornby America, Inc. Rivarossi HO scale Big Boy

Hornby America, Inc. Rivarossi HO scale Big Boy

By | May 22, 2009

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Hornby America, Inc. HO scale Big Boy steam locomotive
Hornby America, Inc. HO scale Big Boy steam locomotive
Hornby America, Inc. HO scale Big Boy steam locomotive
With a coat of factory-applied grime and rust, this HO scale Big Boy looks like it’s seen years of hard use. Since the late 1960s Rivarossi has manufactured Big Boy 4-8-8-4 locomotives in HO scale. This is the first Rivarossi Big Boy to be weathered and to include a dual-mode Digital Command Control sound decoder.

Prototype. The 4-8-8-4 Big Boy is generally acknowledged to be the largest steam locomotive ever produced. The Rivarossi model represents one of the first group of Big Boys (nos. 4000 to 4019) delivered to the Union Pacific by Alco in 1941. The UP received five more Big Boys in 1944.

The UP developed the articulated, simple-expansion 4-8-8-4 to handle the steady grades on the line between Ogden and Wasatch, Utah, without a helper. The Big Boys were also fast enough to keep up with the UP’s steady traffic flow. The locomotives made their last regular runs in 1959. Several Big Boys have been preserved.

Factory-applied weathering. The weathering on the Rivarossi model is quite heavy. Compared to color photos that I found, the weathered model doesn’t capture the look of an aging Big Boy in the 1950s.

An especially heavy coat of rust and brown cover the locomotive’s running gear and lower part of the tender. Additional streaks of rust follow the rivet seams along the tender’s water tank. There are also white streaks down the boiler under the pop-off valves, simulating the mineral deposits or “scale” left behind from condensing steam.

The lettering on the locomotive and tender is straight, neatly applied, and matches prototype photos. Smaller printing, such as the test stencils on the air reservoirs, paint stencil on rear of the tender, and the builder’s, equipment trust, and superheater patent plates are legible under magnification.

The Big Boy’s tender features wood-plank detail on the deck and an operating backup light.
The Big Boy’s tender features wood-plank detail on the deck and an operating backup light.
Dual-mode DCC. The dual-mode ESU LokSound DCC decoder is mounted on top of the motor inside the boiler. A single speaker faces upward in the smokebox. The large centipede tender (perfect for a speaker enclosure) is empty except for a backup light and a two-wire cable that connects it to the decoder in the locomotive.

In DC, the model started moving at 7 volts and features the sound of four chuffs per wheel revolution. As the locomotive’s speed increased, some chuffs overlapped, simulating the front and rear engines going in and out of synch. The overall sound quality is good, although the chuffs have a short staccato quality when compared to those of a prototype steam locomotive.

When the locomotive is still, random sounds play, including the air pump and water injector. There’s also the sound of a fireman shoveling coal, although the prototype was stoker-fired.

There are more sound and programming options available in DCC. The model has 13 DCC functions, including a bell and a long and short whistle. The decoder supports 14, 28, or 128 speed steps.

I easily changed the model’s long address to the locomotive number. The decoder features many adjustable configuration variables (CVs), including the individual volume levels of the bell, whistle, and random sound effects. A list of all the programmable CVs is available in an extensive user manual that can be downloaded at

In both DC and DCC the Big Boy has impressive speed control. The model crept along at 1 scale mph without any binding or hesitation and accelerated to a top speed of 68 scale mph (55 scale mph at 12 volts in DC mode).

Model construction. The tooling and mechanism of the model are the same that Rivarossi has used since it introduced its HO Big Boy in the late 1960s. Most of the model’s dimensions match drawings in the Model Railroader Locomotive Cyclopedia Vol. 1: Steam Locomotives. (Kalmbach Publishing Co.) There are some compromises to scale fidelity to help the model achieve an 18″ minimum radius.

On the model, the pilot truck and front engine are about a scale foot farther forward than on the prototype. The drivers are just under 64 scale inches in diameter, while the prototype had 68″ drivers. The four-wheel lead truck on the tender is a scale foot farther forward than the prototype.

The Rivarossi Big Boy is built primarily of plastic with crisp molded detail, such as the rivet seams. Separately applied detail parts include handrails, throttle linkage, and aftercoolers on the pilot deck. A package of user-installed brake hangers and cab handrails is also included.

The flywheel-equipped can motor inside the boiler has two worm gearshafts connected to gearboxes on the third axle of each engine. The side rods transfer power to the rest of the axles.

The third set of drivers on the front engine has traction tires, which contribute to the model’s impressive 5-ounce drawbar pull. A set of user-installed drivers without traction tires is included.

I ran the model through 18″ radius curves without difficulty, although it looks much more realistic on broader curves. The rear engine on the locomotive pivots, as does the rearmost wheelset in the pedestal truck on the tender. This is unprototypical, but helps the Big Boy negotiate tight curves.

When maneuvering through a yard on our layout, the Big Boy stalled through some turnouts because of the model’s limited electrical pickup. The locomotive picks up power through a total of eight wheels: the left wheels on the lead truck, the right wheels on the trailing truck, the first and fourth drivers on the left side of the front engine, and the first and fourth drivers on the right side of the rear engine. None of the tender’s wheels picks up power.

Hopefully the firm will address the power pickup issue for future releases. The Rivarossi model has great slow speed performance and a smooth mechanism that operates well on both DC and DCC layouts.

HO scale Big Boy
Price: $419.99 ($329.99, DC)
Hornby America, Inc.
3900-C2 Industry Drive East
Fife, WA 98424
Road numbers (all Union Pacific): no. 4014 (DCC), no. 4007 (DC)
Dual-mode DCC sound decoder (DCC version only)
Factory-applied weathering
Five-pole skew-wound motor with flywheel
Metal RP-25 contour wheels in gauge
Minimum radius: 18″
Operating magnetic knuckle coupler mounted at correct height on rear of tender
Weight: 26.75 ounces (engine and tender); 18.5 ounces (engine only)

25 thoughts on “Hornby America, Inc. Rivarossi HO scale Big Boy

  1. How many Big Boys do we need? I know this is a re-release of the first plastic Big Boy model, so I suppose from a manufacturers point of view, why not? Too bad it has not been truely upgraded to todays standards. I wonder if they have any plans to re-release the Cab Forward?

  2. An interesting model of a famous locomotive. Too bad about the "over weathering". At the moment I am an armchair modeler, but I have N scale packed up in the basement waiting for that moment I can put it all together. I also have an N scale model of Big Boy.

  3. Hi Brandon,
    Regarding your question about sounds in DC, the chuffs and background sounds work. There isn't any way to trigger sounds such as the whistle or bell.

  4. Sorry…. Still the old tooling.
    This is just putting paint on an old model. Perhaps we are seeing why Rivarossi is now owned by Hornby.
    Put 68" drivers with RP 25 flanges on it. Add more separately applied detail, and let us worry about weathering.

  5. I too am wondering if they plan on releasing other former earlier models such as the B&O 2-10-2? Using RP 25 wheel profiles will allow closer to correct wheel diameters and spacings. As for factory weathering, my opinion is let the modeler do what he thinks is appropriate for the era and location he plans on using the locomotive in. The Big Boy is a great model from them but not up to todays' standards.

    One final comment, locomotive sound belongs in the locomotive not the tender and multible speakers on larger locomotives replicating the sounds from where they would actually come from on the protype.

  6. I have the DC unweathered version. A nice loco that runs well. Would love to get a sound decoder for it. Need larger curves instead of 18" radius.

  7. You seem to criticize this Big Boy for having the speaker in the engine while there is ample room for one in the tender. Where did most of the sound come from in the prototype? Seeing a Mallet silently pop out of a tunnel is kind of disappointing when the noisy tender follows it.

  8. Believe me U.P 4000s got dirty in road service,they probably didn't wouldn't have stayed clean for more that 50-100 miles though the weathering on this one is ratther unimpressive,have done much better myself.
    Now as to the model what is there really to like.
    not much when there are several superior models out there PCM, BLUELINE, ATHEARN. compared to this piece of old tooling revisited. The engine sound is o.k (passable though the whistle and bell are horrible the bigboy had what was discribed as a steamboat whistle ,very deep in tone not the pathedtic sound in this model, and the bell sounds like a schoolhouse knockoff

  9. I have an original Rivarossi Big Boy and am disappointed that Hornby-Rivarossi did not upgrade its original tooling to include scale drivers etc. Seems a waste of time producing a model whose vitage is now at least 3 to 4 generations old in terms of railroad modelling techniques and accuracy. In any case, we have sooo many Big Boys on offer nowadays that I would find it difficult to buy this one.

  10. I already have an old Rivarossi Big Boy and a TRIX Big Boy without sound.
    Having recently bought some sound-equipped locomotives and having appreciated the new world opened by sound, I am very interested in this new release by Rivarossi, given also the very good mechanical qualitiese of this locomotive

  11. UP did their best to keep their engines clean, but even they could not keep up totally with the grime that accumulated daily. Having said that, I must admit that they rarely got that bad. And I agree that updating the design and fabrication of this one could have helped a lot. I have both N and HO models of this engine, and there is no improvement in this one over what I already have. It will be cheaper for me to just upgrade with DCC and sound than to buy one already equiped.


  13. As another Illinoisan I have to agree with JAMES NEUBAUER who mentioned its to big for my layout but none the less it sure is pretty.

    By the way if you enjoy steam, last week my wife rented from Netflix, "Steam Around the World: The Asian & Australasian Archives". Transfered from film to video the pictures are excellent and the audio track is also good. Folks you'll enjoy this 60 plus minutes.

  14. Hi I was wanting to know how do you work the sounds in DC? Dose the model just play ramdom sounds? Just was asking before buying.

  15. I have an old Rivarossi Big Boy #4001 (5413) and it sounds like the basic design is the same (only no sound, DC only).

    The electrical pickups for the drivers are easily damaged if you get oil on them, the internal spring will be heat-damaged and lose their "spring". Luckily, Kaydee knuckle-coupler springs can be used as replacements. After the repair I've had no stalling issues (it's possible the unit reviewed has this problem, the article mentions it stalls on yard track).

    I've replaced the incandescent headlight with a LED (Radio Shack 276-0017 sanded to fit) with a 470 Ohm resistor and a small filter to get rid of the LED blue light (1/2 CTO lighting gel cut from a sample book)

  16. Perhaps over weathered, but a nice machine if its ANYTHING like the red-box Rivarossi's. I have had mine 8 years as DC and 2 years with an MRC sheer Brilliance with only one problem of the traction tire slipping off. Even that could be attributed to me trying to pull too much. I just have never had the nerve to put weather on it! I too would like to see a cab fwd!

  17. I have an Athearn Genesis Big Boy and whilst detailing is really nice the MRC electronics leave a lot to be desired. I hope the new Genesis with QSI electronics will be significantly better. Having said that I also have a Rivarossi FEF-3 – DCC ready version and it is nicely made, is very quiet when running and has responded well to the TCS MC2 decoder that I have in it. I hope Broadway can retool and do a nice Paragon or Hybrid version that's nicely detailed buy not crazy expensive like some of the Brass or Trix versions are. Comment regarding UP never allowed the 4-8-8-4 to get so dirty is an odd one, recently an issue of Classic Train featuring the Big Boys at night clearly showed how grimmy they did get in day to day service?

  18. My desktop has a picture of Big Boy 4004 toward the end of its life and the weathering is a lot nastier than the model. You can hardly tell the smoke box is silver for all the rust streaks.
    I have an older vintage of this Big Boy and it is a great model for those of us that couldn't afford brass at the time.
    I'm not sure if I could justify the difference in what Hornsby gets for the lastest version now with the old tooling compared to what I paid for the old, even allowing for inflation, weathering, DCC and sound. Maybe the weathering masks the comparison to modern plastic locos.

  19. I also have aquired a "Red Box" DC version of this model. I will weather it myself and install a twin speaker QSI DCC system in the tender. I have not had any "pickup" electrical issues with mine so far. I also own a PCM "DC" Big Boy and a Trix Big Boy with DCC and sound. PCM & Trix are definately superior models with die cast bodies & finer detail, but also more expensive. I still like running the Rivarossi engine as it is impressive to watch and a good model for the price.

  20. well the weathering on this model is like it sat in the deadline for 5 years , not on a active line

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