I’ve got a question for you train guys (and gals), I have heard of steam locomotives built with 4 cylinders per set of drive wheels: 2 high pressure cylinders on the inside of the frame and 2 low pressure cylinders on the outside (I might be backwards on that but it doesn’t matter for my question). Were there any steam locomotives built with 3 drive cylinders (all high pressure, 2 on the outside and one centered) and if so, were the wheels “quartered” at 120 degrees as opposed to the common 90 degrees?
Yes, there were some 3 cylinder locomotives built in the US in the 20’s. The Union Pacific had a fair number of 4-12-2’s IIRC. Don’t quote me but I think there were some tried in the East but no sizeable fleets that sping to mind. Most RR’s ddn’t like them because of the inacessibility of the inside cylinders for maintenence. Such things were more common in Europe, where locomotive efficiency was more attactive than the brute force though sheer size approach we took in this country.
Based on what I have read, yes, the drivers were “quartered” at 120 degrees, rather then the two cylinder 90 degrees.
As I recall Baldwin built one or more 3-cylinder experimental engine(s) for the B&O. I think the Delaware and Hudson had some at one time. There was a whole fleet of Pacifics in England, but I forget which railroad, also I believe some ten wheelers. Many of these locomotives were eventually rebuilt into conventional two-cylinder locomotives, since the inside cylinder and espcially its valve gear were difficult to maintain. I am sure there were a lot of Euorpean examples since complexity thrives better there! In diesels too!
Three cylinder locomotives were all the rage back in the early part of the 20th Century. Many railroads had them but most removed the third cylinder due to the difficult maintenance.
The D&H had several odd 2-8-0s that were three cylinder and the steam was used three times before being exhausted. These locomotives couldn’t move very fast but they could pull a lot of cars and move them on very little fuel.
The ultimate 0-8-0’s; IHB U-4a’s 100-102, had three cylinders. I don’t think that they were ever rebuilt. Complexity seems to thrive in Europe for a variety of reasons; steam locomotives often were assigned to dedicated runs and and more shop time was the norm, labor was relatively cheap compared to fuel; etc.
Actually, if I recall correctly (I’m at work and my brain doesn’t work at work…) the ultimate D&H 2-8-0 was a 4 cylinder triple compound. Two cylinders at the rear of the frame, two in the conventional location at the front. It also used a very high pressure water tube boiler. It did not lack speed – just as fast as any other engine with drivers that size – and was very economical. It was also a maintenance headache, as all four cylinders drove on the same axle, and the resulting loads were too great for the bearings.
The true three cylinder locomotives might or might not be compounds; there is nothing which says they have to be, or can’t be. Whether they were or not, the major problem with them (as has been noted) was maintenance of the valve gear for the middle cylinder. There were basically two ways to control this cylinder: either have a separate s
The Baldwin #60000, on display at the Franklin Institute in Philadelphia, is a good example of this type locomotive. Here’s a shot of the cylinder saddle:
http://www.cwrr.com/Lounge/Reference/baldwin/fig7.jpg
The entire paper on this locomotive:
http://www.cwrr.com/Lounge/Reference/baldwin/baldwin.html
The center cylinder was the high pressure one, and the outside ones were the low pressure, so this was operated as a compound.
As noted before, three cylinders were fairly common on European steam-engines that were designed für fast passenger-trains. (unlike diesels, builders used to design steam-engines to predefinded services, i.e. fast passenger, local stopping trains, heavy haul freight etc.) Three cylinders are a reasonable compromise between two and four cylinders. steam-engines with two cylinders are cheaper to build and to maintain, but they ride rougher. For slow freight-trains, hump-yards or local stopping-trains, this doesn’t matter. There, the economics of the two cylinders prevail, with the exception of course of Mallets, Garrats and duplexes. Four-cylinder engines on the other-side have better riding-qualities, if designed well, but are more expensive. The German standard-pacifics of the 1920s and 1930s (class 01 and 03) had three cylinders each. The last batch was rated at 150 kilometers per hour, roughly 90 mph. As to other countries like France and Britain, I am not knowledgeable enough to give an answer, but IIRC, the A4 pacifis of the LNER - world record for steam-locomotives - had four cylinders.
Until somebody goes down to look at the SP 5021, we can’t say for certain, but it’s an excellent bet the outside cylinders are 120 degrees apart. The center cylinder is less clear-- it’s inclined 9.5 degrees, so I assume its crank is positioned 110.5-129.5, but that will be a bit harder to confirm.
As I recall one of the characteristics of the UP (4-12-2 and 4-10-2) and SP (4-10-2) engines was their “synchopated” exhaust which went something like “chuff chuff chuff chuff chuff chuff chuff chuff chuff chuff chuff chuff” which would indicate other than a 120 spacing.
Martin,
There are a couple of errors in your explanation.
The German Pacifics of classes 01 and 03 built in the 1930s and 1930s were standard two cylinder locomotives. There were a few four cylinder compound pacifics of classes 02 and 04 built at this time. Later two streamlined pacific classes 01.10 and 03.10 were built during the early 1940s. These and the 4-6-4 class 05 had three simple cylinders, and these were allowed high speeds.
The LNER Class A4 and all LNER pacific type engines had three simple cylinders. The LMS locomotives of the Princess and Duchess classes had four simple cylinders. The Great Western 4-6-0 locomotives of the Star, Castle and King classes also had four simple cylinders. The large 4-6-0 locomotives of the LMS, (Royal Scot, Jubilee, Patriot) however, had three simple cylinders.
M636C
The UP 9000’s had 120 degree spacing and were not compounds. The middle cylinder had a 1 inch smaller stroke than the outer cylinders and it’s exhaust was siameesed with the left cylinder which could account for the sound. They were built with the Greasley arm system, but some were later converted to double Walshaerts gear hung on the right side. These are easy to spot as they had their air pumps moved from the smokebox to the left side for better balance. Steam works both sides of the cylinders in steam locos, so a 3 cylinder loco has 6 exhausts per driver revolution. UP’s 4-10-2’s were all converted to 2 cylinder locos by the LA shops and ran on the Southwest district while the 4-12-2’s ran to the very end across Nebraska on all 3 cylinders.
NH had some 4-8-2 and 0-8-0 with 3 cylinders. Also I think DL&W.
The Pennsylvania RR Museum at Strassburg has a 3 cylinder engine arranged so that you can walk under it and see the inside cylinder.
Would also like to note that there were 4 cylinder compound engines that had all cylinders outside. The high pressure ones were mounted above the low cylinder ones, each with their own piston of course. They look much like a standard engine with piston valves, but the valves on these are hidden by the high pressure cylinders.
Art
Those are Vauclain Compounds after Baldwin design Engineer Samuel Vauclain who designed the arrangement. Another design was the Tandem Coumpound with the high pressure cylinder located behind the low pressure cylinder, they drove one piston rod per pair. Not successful either.
Many US railroads tried at least one batch of 3-cylindered locomotives, The DRG&W 1600 series Mountain type, MP had a batch of Pacifics, as mentioned the Lackawanna had a batch of 4-8-2s, as did the Lehigh Valley.
im sure most engine manufactures late 19th century made experimental engines…seem to recall Burlington had some 4 cyl compounds in 4-4-2 1890ish
Although generally less than completely successful in railroad applications, cross compounds and tandem compounds were successful as marine engines on steam-powered towboats on the Mississippi and Ohio Rivers. Vertical triple expansion compounds were also the standard on ocean freighters and liners prior to steam turbines. Liberty Ships in the WW2 era used VTE engines because they were easier to operate and maintain for inexperienced ship’s engineers.
The axes of the cylinders were vertical? With three cylinders stacked? How tall was it?
No the cylinders weren’t stacked, the pistons just moved in the vertical plane. If you get the chance visit the Battleship Texas at the San Jacinto Battlefield south of Houston, she is equipped with a large VTE engine. Vertical Quadruple Expansion (VQE) wasn’t rare either.
IHB had 3 cylinder 0-8-0’s, DLW also had 3 cylinder 4-8-2’s which they converted to 2 cylinder locos