# Articulated Buddy L 2-6-6-6-2-CONTINUED



## Festus (Jun 28, 2010)

[No message]


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## Scottychaos (Jan 2, 2008)

I think you can safely ignore the "3rd set of drivers needs to be under the tender" idea.. 
people say that, because the only 2-8-8-8-2's that ever existed were set up that way: 










but..that doesnt mean your has to be set up that way! 
since yours is clearly "freelance" there is no reason to stick by exact prototype practices.. 

and, if you want to make it cab-forward, then I especially wouldn't worry about putting the last set under the tender.. 
since no cab-forwards were set up that way..










The project already looks complicated enough as it is..adding a set of drivers under the tender would make it even more complicated.. 
no reason to do that at all IMO..unless you want to..but you certainty dont *have* to.. 




If the front and rear wheels are articulated, and the center set of 6 is fixed, 

I dont think you can have a solid, un-articulated boiler..its simply too long.. 
instead, perhaps consider building it with three separate articulated units, all attached.. 
each of the three sets of drivers, and the boiler sections above them, will need to be articulated from each other set.. 
and the drivers will *not* swivel under their individual section of boiler.. 

I dont really think you will be able to build this using "prototype articulated" practice.. 
on the prototype, the rear set is "fixed", not articulating.and the front driver set is articulated.. 
For this model, I think you will have to have three separate "units"..with drivers firmly planted under their individual sections of boiler, 
then have two articulated joints between the three sections.. 

*the boiler sections will need to be hinged as well*.. 

IMO, the boiler is simply too long to *not* have a hinged boiler..unless you have something like 50 foot diameter curves.. 

personally, I don't think its a practical project..but that's just me!  
if you want to give it a go, more power to you! 
The Santa Fe did try an articulated boiler, with little success..but there is a prototype precedent: 









Scot


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## Charles (Jan 2, 2008)

A project similar to this topic was successfully completed in live steam and operates well on layout:
The build overview:
Quadruplex 

In action:
The Quad


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## DKRickman (Mar 25, 2008)

It all depends on what you like, Festus.

If you want an engine which looks plausible, then you more or less have to stick to prototype practices. That doesn't mean you have to model a real engine, but you ought to at least think about how a real builder would have done it. If, on the pother hand, you want something unique, with no requirement of plausibility, then you have a much wider array of options. I cannot tell you which one is better, as it is a very personal decision.


With that in mind, here is what I have to add to the discussion:

From a strictly mechanical point of view, making the center set of drivers rigid makes the best sense because it leaves the overhang about the same on both ends. Remember that you will need to hinge the front and rear frames off of the center, rather than attaching them to the boiler (unless there is a LOT of side play in the drivers of the center section). Unless you use a sliding pad to transmit weight from the boiler to the drivers, the only weight (and thus traction) they will have is whatever you can put inside the frames. The pads would work well for horizontal curves, but would effectively make the model rigid on vertical curves. It seems that you have a choice - a fairly weak model (compared to the way it looks), or one which is prone to derailments on the gentlest grade.

A slightly better arrangement (though slightly more difficult to build) would be to let the front and rear sets pivot around points somewhere inboard of their centers (the exact point would be set to equalize inside and outside overhang on curves), while the center set floats both vertically and horizontally. What I would probably do would be to mount it on a swing arm, similar to a pilot truck, which would let it move up and down, side to side, and rotate. Since in theory the drivers would be pulling the model, the swing arm would trail the center chassis. That way, the model basically becomes a double 0-6-0 trucked engine, and the center set is just along for the ride.

So much for the mechanical issues. If you want this beast to be prototypical, then you probably want to keep it down to two sections under the boiler, or introduce a hinged boiler as Scot mentioned. If you want to use 3 engine units, put one under the tender. If you want to use 4, put two under the tender, either as trucks, or as a mirror image of the front, with one rigid and one hinged. I would also re-think the design of the boiler. A boiler that long would not be very efficient, especially if it was that small. A larger, shorter boiler with a fairly long firebox and a lot of extra frame showing up front would be much more reasonable from a prototypical point of view. The shorter boiler (stopping somewhere around the middle driver of the front unit, I would guess) would also help with reducing the overhang on curves.

Another alternative with some basis in reality would be a Mallet Garratt. Think of a pair of 2-6-6-2 Mallets, but instead of boilers you mount a tender on one and a water tank on the other, and sling a lowboy frame with a short fat boiler between them. It becomes a 2-6-6-2+2-6-6-2. I don't see why it couldn't be a cab forward, as well.









Whatever you do, it promises to be interesting!


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