I understand that the various shapes of locomotive diamond and funnel stacks was purely functional, to accommodate the placement of spark screens. Eventual practice took these screens out of the stack and placed them in the smokebox, so the diamond shape was no longer needed. Thus the stack was changed to the straight shotgun stack, which grew shorter as the clearance diagram was filled with the expanding sizes of locomotives. However, during this transition, the cap or flange stack became popular. Was this style of stack purely decorative or was there some functional purpose to it? If there was no functional purpose, could it be that the flange stack was merely a way to ease the aesthetic transition from the diamond stacks to shotgun stacks? RTK

stacks did not grow shorter, you just do not see most of it on later locomotives, it's hiding in the smokebox.

Ron,do you mean a capped stack like this?http://ourworld.compuserve.com/homepages/rea_home/lv04p.jpgif so, that fluted cap is purely decorative!just for style..that is the Lehigh Valley's "consolidation", the first 2-8-0 road engine..built 1865.this was still the height of the decorative locomotive era..right up through the late Victorian era of the 1890's, locomotives remained quite artsy..it wasnt really until the early 20th century that style totally gave way to strict boring functionality.locomotive also lost all of their color about then..thats when "basic black" came into effect.for most of the 19th century, locomotives had all kinds of bright colors and fancy gold trim.Scot

I've always wondered about "capped stacks" myself. Evidently the terminology has different meanings in different places. My understanding was that these "caps" of either sliding or flip over type were for when locomotives were stored outside. The railroads had a lot of extra motive power during the depression, and that seemed to be when these devices showed up. Can anyone enlighten me further?Fred

Interesting points all. I do recall that the Milwaukee in particular had hinged covers on the stacks of their later steam locomotives. They could be flipped over the top of the stack to “cap” it if the engine was left dead outside. But, by cap or flange stack, I am referring to the type of flare on the stack in the photo posted by Scott. I too would assume that this stack feature was purely decorative, and would be very surprised to learn otherwise. I am familiar with the decorative era giving way to pure functionality of the 1900s, and I understand that the cap stack was frequently used throughout the second half of the 1800s, fully within that decorative era.However, the phase that I am concerned with is the sweeping change from short smokeboxes with diamond stacks to longer smokeboxes with shotgun stacks. Besides the shift being reflected in new manufacture, there were many 4-4-0s that were rebuilt with the change. But instead of shifting directly from diamond to straight stacks with the smokebox change, many of these engines went from diamond stack, to cap stack, to straight stack. This was about the time the decorative era was ending, so I suppose the short cap stack transition phase was just an emotional concession to the pain of letting go of so much with the loss of the diamond stack. If that were the case though, it would mean that the diamond stack was accepted as an aesthetic contribution to the decorative character even though it was purely functional, whereas the functional straight stack was considered lacking in style. However, if it were strictly for appearance, it seems surprising that some roads such as D&H, T&P, Cottonbelt, and the NC&StL used the flange stack right up to the end of steam. It is hard to imagine any railroad company paying for what amounted to a hood ornament so far into the functional era. RTK

In terms of the fancy flange (capped for me means 'covered') perhaps in later steam (early-mid 20th century) a railroad would like their fancy engines on the crack passenger trains, which were the flagship of the railroad. You would like to convey to the public that your consist is of the nicest equipment, especially if you(passenger) have another railroad to choose service from. Now a locomotive rebuilt over and over probably is demoted from service. Perhaps it began on a fast mainline passenger train, but after it was rebuilt after a decade or two of service, better locomotives replaced the earlier model, and the older engine serves a branchline or local freight. I always noticed the difference in the Detroit & Mackinac ten wheelers. As-delievered they were pretty engines, but after they were rebuilt they were hideous, well, not ugly, but they were obviously hacked to improve their performance.

I remember reading once that the flange or cap was for when you had to store a locomotive. You could tarp the stack and the flange would give you something to wrap the rope around. With a perfectly straight stack, the wind may blow the tarp and rope right off. It sounded like a logical reason when I read it, at least.

Well, technically, the stacks did get shorter. As boiler/smokebox diameters got larger, the stack had to get shorter. The petticoat pipe is the part seen inside the smokebox. While it may be considered a part of the exhaust stack system, it was a separate pipe suspended inside the smokebox to control and direct the flow of the exhaust gases from the firebox and steam exhausted from the cylinders.Georgia Northern 107 has a decorative stack flare or "cap". It is formed copper that was nickle/chrome plated and attached to the exterior of the cast steel stack, which also has a flaired rim as an integral part of the stack casting. There is some indication that the "cap" was added by the Georgia Northern after it was bought from FEC. We are looking, but so far have not come up with a photo of FEC 88 with a decorative "cap". None of her sisters on the FEC seem to have a "cap", either.The Atlantic Coast Line "Copperhead" ten-wheelers were so named for the decorative copper flares on the stacks.

Here's an example of what Chris is talking about. Check out the tender modifications and the superheater conversion. Has the smokebox been extended from the original? And does that qualify as a capped stack or a shotgun stack?Fred

Maybe cap stack is the wrong terminology. I always assumed it was synonymous with flange stack, but now I’m not so sure. Anyway, flange stacks are what I meant. Chris, I know exactly what you mean about locomotives losing some of their as-built good looks over the course of periodic rebuilding even though the changes made a better locomotive. I mentioned the common, widespread rebuilding of 4-4-0s by lengthening the original short smokebox. This was, no doubt, a functional improvement, but I think I’m not alone in saying it harmed the appearance in most cases. It was not the length of the smokebox per se that harmed the look, but the engines were designed with the short smokebox, and all the features were balanced by the designer. The remodel upset the balance.Fred, I would say that stack on D&M #133 is not a flange stack, but your question raises a point. Most if not all shotgun stacks as well as shorter, modern stacks have a lip feature cast around the top. Is that functional? It is extra iron. Is it there to reinforce the stack opening against stress cracks that might start at the edge? Or is it simply what the more pronounced, decorative flange devolved into in the interest of trading decoration for economy? RTK

Well, smoke stacks are an iron casting and I worked in a foundry for 36 years. Definitely makes for a stronger casting with an enlarged lip. Also simplifies locating the patterns in the mold. Even late model locomotives had a lip on the top but it was dwarfed because the stack itself was so big.Fred