So, first off, your going to worry about me since I’m dropping it onto a 2-8-4+0-8-2 cab forward, but I’m crazy, so let’s do this. (General thinking is lose 10mph due to second drivers (recycled steam) gain 40 miles beofre having to make a fuel stop=faster freight schedule)
I’ve been poking around the web, so far all I’ve found is a frameowrk on the boiler, ossibly sme weights, and then tossing the styrene on top of it with traced spots for the domes. Since I’m piutting it on a Spectrum shell, I doubt I need any more weight on the engine. I can;t imagine it’s all that simple though. (Will gladly be wrong) Is there a limit to length, someplace I shouldn’t put a thermos on for boiler heat reasons? It’s going to be an oil burner, is there a general fuel/water ratio? my thoughts were that by moving the water and increasing it somewhat, the fuel bunker in the tender could be increased as well, or is an oil bunker on top of a set of drivers a bad idea?
Crazy? No doubt about it. Not sure what you mean by putting on a Spectrum shell, so my following comments may be for naught.
All the SP backward Yellowstones were simple steamers. Compound steamers had larger cylinders for low pressure and smaller cylinders for high pressure. SP’s earlier articulateds were Mallet (compound steam) locomotives which were later simplified.
The locomotives were about as wide/high as you could get prototypically. Adding saddle tanks would increase width/height significantly. You would need a smaller-diameter boiler, but that would surely decrease the locomotive’s “prototypical” hauling capacity. A boiler is more efficient if it is insulated, so don’t worry about covering the boiler (but not the smokebox) up with tanks.
The ratio of water to fuel was usually about 3 to 1. If you altered the tender for more fuel, you’d probably need to change the rivet detail to show the new water/fuel boundary. An easier solution may be to have split saddle tank(s) between fuel and water if you’re scratchbuilding the tanks anyway.
None of that was not useless, some if it even stuff you saved me from asking later.
My choice on compound was simply to save a single engine boiler from trying to feed two sets of pistons, and end up woth another Triplex failure that can only do 15.
As far as width goes, I was just going to take the tank out to the edge of the existing lefge, and if someone felt so neccecary, build a sereis of stirrup steps along the side. Or not, we’ll see. That’s still roughly 1.5ft wide, roughly 50’long, and 4 ft high. For sake of simplicity we’ll acll it (2/3)1.550*4 is 200 cubic feet *7.5gallons per cubic foot is roughly 1500 gallons of water. Not alot compared to a tender which is 22,000, but it’s more than what they started with. That 2/3 was me guesst
The Triplex was a compound engine. Compound engines aren’t noted for their high speeds. The Triplex’s problem was that it couldn’t generate enough steam so speed was further compromised.
If “used” steam is used to power the pistons under the tender, larger pistons are needed. Engines with opposite-facing pistons were produced, but I don’t know if there was an inherent problem with this arrangement. The second drivers needn’t be the same diameter. Look at the pictured locomotive where the smaller drivers of an obsolete Consolidation were placed under the tender of the Mikado making it a 2-8-2+2-8-0. It appears that high-pressure steam was fed to all cylinders, but that’s my presumption.
The above model is based on a Southern Railway prototype but modified to use oil as fuel for Dick Truesdale’s (of Westside Models) personal layout. I was told he had five of them produced just for himself, and they
This is not the way real railroads solved this problem – but that’s apparently of no matter to you. Real railroads which wanted to extend the runs of large locomotives by minimizing water stops added an auxiliary tender (called a “canteen” on the N&W, for example).
Seems like a lot of work to create a never-would-be whimsical tank engine, but that’s just my opinion.
Yes, I know this. 4449, 587, 2101/AFT 1 and 614 all have them as well. But if I add water, I still have to stop for the same fuel points.
Yes, I am experimenting with an engine, much like the Southern example above. (Gee, I like that. Might be my next failure project) A stronger loco, without needing the fuel stops, and ftting on most standard turntables. So I’m going to have fun with this. May we go back to my having fun pwease?
Okay then, so simple steam is the better way to go for a balance of speed and power?
