Allegheny 2-6-6-6 Engine (2024)

I figured that since I had been a member of the Greater Portland Lego Railroaders for some time I ought to actually make a train. I decided on a steam engine, and as long as I was making one in Lego I figured it may as well be a big, cool one. So I found the 2-6-6-6 Allegheny and decided to model it, as my first MOC train engine in about 15 years (since I was a kid), and my first ever MOC steam engine.

During my research I found that the Allegheny is pretty much the coolest and one of the biggest steam engines ever (of course there is always debate there). But consider this - the final Allegheny's delivered weighed 1,207,000 pounds with fully loaded tender (that is over 500 metric tons!) which makes them the heaviest steam locomotives ever built in North America. And they were right up there in the rest of the rankings, too.

This is the prototype that my Allegheny is based on. This picture is from page 16 of the February 2002 Model Railroader magazine. The model shown is by Rivarossi, and it has a nice write-up. Other good pictures were found on ebay where this same model is being auctioned since it is no longer in stores (prices were around $500 in May 2002 when I was checking, pretty close to the suggested retail price of $585 (and you thought Lego was an expensive hobby!)).

This is my version of the Allegheny 2-6-6-6. Note that the tender is also scaled similarly. There has been selective scaling in my model to bring it down to Lego scale. The HO version of the Allegheny is 17" long, where as the Lego version (close to "O" scale) should be about 34" long, mine is only 29" long with tender (about 6 track lengths). My model is mostly 7 studs wide with a maximum width at the driver wheels of just under 10 studs. The boiler is 6 studs wide and the white stripe is entirely 1x2 jumpers so everything below the stripe is 7 studs wide.0103

Here is a view from on top. Overall length is about 92 studs.

Here is a top view. Note that the cab is all 7 studs wide and there is plenty of room inside for an engineer and a little room for a fireman. The white 1x2 jumper offset is clearly visible in this picture.

Here is a front view. The front detail below the boiler was some of the most challenging and fun building on this model. The linked wheel set here includes the front guide wheels (12V wheels) and the first set of 6 driver wheels. The wheels are all stud-down, so the front detail had to incorporate that and convert to stud-up before the railing detail at the headlight level. The bell on top is the same piece I used for the headlight.

A head on view. The real thing is over 1 million pounds so stay out of the way! There is a pretty good view of the edge of the steam piston things (sorry, I don't know my technical steam stuff). The right one is missing a black 1x1 dot. I build them out of 1x3 Technic 1/2 width beams. The look great, but the Technic drive rods don't slide in the resulting hole well - it isn't smooth enough.

A view of the front side. I remove the driver rods when I actually run the train around the track (but not the rods connecting the wheels).

A close up of driver wheel detail and such. You can see the steam piston things really well with the driver piston rods coming out of them. Those are the rods I usually remove when running the engine to make for smoother running.

Here is the best shot I have of the cab, and a good shot of the tender. Sorry I have such poor quality stickers made up. The engine and tender are coupled with standard magnetic couplers. Note the ash box on the far right of the picture, sided with "wing" plates on edge. When the engine is "powered" the front wheel set on the tender is replaced with a standard 9V train motor. But then the wheels are no longer prototypical. :( For that you need to switch in a 12V motor and run this on 12V track.

A close up of the rear wheel set of the tender. The actual Allegheny was too long for existing turn tables at engine houses. The solution was to make the rear wheel set on the tender moveable. In the prototype, the final rear wheel set actually lifts up off the track so the engine and tender can ride a turn table.

Mine lifts up too, like the prototype. If you turn a secret 2x2 round lump of coal in the top of the tender internal gearing will lift the rear set of wheels off the track. Unfortunately, this engine is still too long for most Lego engine turn tables. The rear wheel set actually moves in 4 directions - up, down, left and right. The three sets ahead of it are linked solidly, but that is the longest set of linked wheels you can do on Lego track. So the final set must be able to move left and right independently of the first 3 so the tender can navigate corners.

An overhead view of the tender. Note the prototypical 3 water intake hatches, rear ladder, hand rails, rear light and coal bin.

Another rear view of the tender as it starts to turn a corner following the engine.

A bottom view of the tender. I built the tender as solid as I could so as to add as much weight as possible (same with the engine). Note that since the hopper is 7 studs wide the wheel sets must be on a 1/2 stud offset underneath so as to be centered. All the wheels on the hopper are from the old 12V system.

This is a view of the bottom of the engine, looking from the front back. The first set of wheels (the "2") are 12V, the next two sets of 6 are each built with 4 smooth round Technic hubs and 2 round Model Team type Technic hubs. The final 6 wheels on the engine are 3 sets of 9V wheels. The engine body is attached to the wheels at two points - over each set of driver wheels. There is a pivot point between the final driver set and the 9V wheels, which simply float under the fire box and cab of the engine (not touching either). A magnetic coupler after these wheels connects the engine to the tender. Steve Barile took this picture so it is better than most of the rest - thanks Steve!

A close up of the rear driver wheel set. How does it stay on the track? Those 4 hammers are mounted stud-down so the points are down below track level. They act as wheel flanges since none of the 6 wheels in this set have flanges on them. They keep the train on the track and will go through curves, crossings and switches! Pretty cool, huh? Note that the center wheels are different than the outer wheels. The center wheels are the model team type wheel hubs, and they have room for the hammer assembly. Viewed from track side, the hammers are almost completely hidden behind these wheels.

Another view of the same thing as the last picture. Wheel spacing was quite tricky to make the rods between the wheels all turn correctly. Note that the entire assembly is stud down to attach the hammers. Those are hammers from those tool wheels that you never knew what to do with.

Here is a view of the front 6 driver wheels. Note there is only one set of hammers on this wheel set. You need two points to keep your wheels from twisting all over and off of the track. The second point is the 12V wheel set at the front of the train (barely visible in the lower left corner of this shot).

Another view of the hammers on the front drive wheel set. Steve took this picture too so it is a little clearer.

And a view of the bottom of the very front of the train. All stud down as you can see, all because of those darn hammers. The hammers at the back of the picture and the 12V wheels at the front of the picture keep the front of the train on the track.

Yep, it goes around corners. But don't stand too close! It is great for clearing brush from the sides of the track at the corners. In real life there were few tracks that an Allegheny could run on. Track had to be extra strong since this engine was so big - over 1 million pounds with a fully loaded tender! And since it was so long it could only manuever through wide radius turns. In my Lego version I have made it go on any Lego track, but it will go much better on straighter runs and gentler turns. Take those switches slowly!

Another view of going around a corner. This shot was taken at the PNLTC display at the Beaverton Mall in 2002. Jeremy Rear designed the scene and built the cool tractor and sprayer in the background.

There's the real thing! This shot is from the Model Railroader magazine. There are two real Alleghenies left - one at theHenry Ford Museum in Dearborn, MI, and the other at the Baltimore & Ohio Museum in Baltimore, MD. Thanks for checking out my Lego Allegheny!

I hope you have enjoyed the Allegheny! One of these days I hope to rebuild it with Big Ben Brick wheels.

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Last Updated April 28, 2010 - mattchiles@horseshoebendranch.net - Copyright Matthew J. Chiles 2002-2010 all rights reserved.
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