Why were they used and who used them? They seem like a mostly southern thing, and aside from that don't appear to be a dominant design.

John,

The stacks were actually somewhat complicated internally, with cyclones and several layers of screening. They were used predominantly on lines that used wood as a major source of fuel. The Sumpter Valley Railway in eastern Oregon used them on their ten-wheeler and mikado locomotives, the biggest weighing in at over 100 tons. Many of the logging lines in the area used them as well.

Taylor

Balloon/Cabbage stack on the Argent Lumber Company 2-8-0 No. 7 in Hardeeville, SC.

Used to screen the cinders out of the exhaust smoke and keep from setting the swamps on fire.

I am not sure I understand John Hillier's original question. Regarding the stack shown in the photos posted by Jason, I see three possible questions as follows:

1) What is the basic function of this stack?
2) Why is this stack rounded while other stacks with the presumably the same function are diamond or funnel shaped?
3) How do you manufacture that spherical transition piece?


Regarding question #1, I assume that this stack contains spark screens and perhaps baffles to serve as spark arrestors just as the diamond or funnel shaped stacks do.

Regarding question #2, as far as I know, there is nothing functionally about this type of stack that requires it to have that partial sphere shape. And the spherical belt section, with its compound curvature, would be harder to manufacture than the simple curved sheets used in a diamond or funnel stack. So I would like an answer to question #2. Otherwise, I can only conclude that it is made with that spherical transition simply because the maker thought that it makes a better-looking stack.

I assume that the answer to question #3 is that it was cast iron. I cannot imagine that it could be formed sheet because you could roll a sheet strip into the cross sectional profile of a partial curve, but then how do you roll that strip into a circle? So question #3 raises another question of why the piece was made spherical when such a shape required a relatively expensive casting, whereas diamonds and funnels do not.

When I hear the term cabbage stack, I assume that it only applies to these partial spherical stacks. I seem to recall also hearing the term, onion stack, which I assume means the same as cabbage stack.

As I understand it, the term balloon stack applies to funnel stacks, and to perhaps diamond stacks as well. It may refer to all stacks with some type of expanded shape required to enclose spark arrestors. But, in any case, I don’t think it applies exclusively to the spherical stack shown here. This is a bit confusing because the term balloon seems to apply more to the spherical shape than to the funnel or diamond shapes.

In general,. the only stacks that have ever been referred to as "cabbage stacks" have been the rounded stacks seen on the Argent Lumber Co. steamers. Since Argent survived as a three-foot operation on South Carolina longer than most (until 1956-7), and most of its steamers survived one place or another, that's been the "traditional" interpretation of the style.

The Argent locos used what was called a "Rushton patent" stack, which was apparently an aftermarket device applied to all their locos (some were bought used, after all). The Rushton patent dates to 1923, and is an improved version of a design called the Radley & Hunter design. A diagram of the stack, possibly from some Locomotive Cyclopedia, is reprinted on page 79 of Argent: Last of the Swamp Rats by Mallory Hope Ferrell, complete with lifting ring integral to the interior center of the inside baffle construction.

Anyone wishing to pursue this topic further can go online to Google Books and peruse pages 114-123 of A history of the American locomotive: its development, 1830-1880 by John H. White Jr. (the edition posted is the original 1968 edition; I have the revised and expanded 1997 edition beside me now).

Wanna buy one? See if any of these are still available:
http://www.internationalsteam.co.uk/trains/negros05.htm

(It's considerably amusing to do a thorough Internet search on the subject and find a "Rushton Farms" selling bok choy........)

If the following picture link works; it shows the interior of a cabbage stack; with it's baffles. The actual stack is at the Southern Forest Heritage Museum in Long Leaf, LA; it is from a scrapped Shay.

Thanks for that information Alexander. I do have both editions of that book, but it had not occurred to me to check them. There is indeed a lot of information on the various stack designs in them. I get the impression that the Rushton stack utilized the spherical transition to provide an optimum shape for the gas flow, and that the design was perhaps the most advanced in the evolution of spark arrestor stacks.

It is interesting that this design dated from 1923 because I thought that by that time, a consensus had developed prior to 1900 that the spark arrestor screens were best placed in the smokebox rather than in the stack. The Rushton stack seems to have bucked that trend for some reason.

In the photos posted by Jason Underwood, the spherical transition piece appears to be cast iron, a process that lends itself to such a compound curved shape. Yet in the photo posted by James Hefner, it almost appears as though the spherical transition is bent near the line where it is broken away. That indicates that it was made of sheet iron or steel rather than cast iron. If that is the case, I would really like to know how they formed that piece.

Only the center ring, or section, was cast, the rest of the outer shell was fabricated. They were a Baldwin product, and not only put them on woods hogs of their own build, but would sell you one aftermarket as well. They were very popular in the pine forests of the South. Master Mechanics front ends were designed with coal in mind, and the Rushton Stack was the final developement of the Radley and Hunter-its innovation over the R&H was mainly in the way it was constructed, and not in principle. They were very effective when burning lighter solid fuels, and many sugar cane engines built to burn baggasse were so equipped.

W. T. Carter & Bro. used them in East Texas. See my photo essay, Iron horses put out to pasture:
http://railroadglorydays.com/mcsa

Thanks for that information Jim. It does explain why a spark arrestor stack was needed so long after the switch from diamond stacks to the MCB front end. And thanks Glen for your excellent photo essay on the W.T. Carter & Brother locomotives.

On the subject of stacks, there is something else that I have wondered about if I may bring it up in this thread. Around 1890-1900, during the switch from diamond stacks to shotgun stacks on coal burners, there seemed to be a rather widespread use of cap stacks. Was there any functional purpose for that feature? If not, it seems strange that railroads would have been willing to pay for that extra cast iron feature just for appearance when, on the rest of the locomotive, form basically followed function.

Since no one more knowledgeable has answered this, I'll give it a try.

I believe the capped stacks were indeed merely ornamental and had no other function. They were done at a time when the Victorian era of embellishments was ending but wasn't totally over.

Glen

Try these. . . . Everything you ever needed to know about a Rushton stack. Note that BLW specified its use when Radley and Hunter was specified. I suspect this had something to do with paying off patent fees.



Steve

Glen -

The story I heard about capped stacks is that they were easier to "cap" when locomotives were stored out of service. Don't know if that is true or not.

Les

Just to be sure we are talking about the same thing, when I say cap stack, this L&N locomotive on this book cover is an example of what I am referring to:

http://www.iupress.indiana.edu/catalog/ ... s_id=19962

I have also heard of flange stacks, which I assume is synonymous with cap stack. Looking at the L&N engine, I can see how it might be just a decorative element because it repeats a similar feature on the domes.

I have also seen some variations of this stack feature, which have a somewhat different shape, including some on more modern engines.

We regularly see cabbage or Rushton stacks in the west on lines that continued to use wood after 1920 or so... I suspect we associate it with the south thanks to the lumber roads in the region which were among the last wood burning railroads, well chronicled by Beebe and other authors of the 1940/50's

The Radley Hunter design involved a centrifugal feature, which was supposed to spin any cinder heavy enough to start a fire out of the exhaust stream. They were pretty effective, but were prone to being burnt out.... the internals gave out, and as a result needed rebuilding more often than other designs. It was significant issue... so much so that some railroads ordered both Radley Hunter and straight stacks and only used the Radley Hunter stacks when fire conditions required them.

Based on the PDF's posted by Steve Zuiderveen, it looks like the centrifugal baffles on the Rushton are cast, and probably therefore held up better than the baffles in a Radley Hunter (which I assume but don't know for sure are sheet metal).