# Compound steam in 4-4-2s and 4-6-2s - now I've seen everything!



## Jerry McColgan (Feb 8, 2008)

I thought I had see just about everything until I read about compound engines on 4-4-2s and 4-6-2s. I thought surely that the author was wrong because (I thought) compounds were only used on articulated locomotives.

I found this:

http://www.answers.com/topic/vauclain-compound

http://en.wikipedia.org/wiki/File:V..._steam.PNG

but I guess you just cannot see it from side view pictures.

http://upload.wikimedia.org/wikiped...o._919.jpg

That led me to:

http://en.wikipedia.org/wiki/Compou...nd_systems

Configurations 
 
Vauclain four cylinder compound locomotive Milwaukee Road class A2 No. 919.




There are various configurations:
[edit] Two cylinder compound [*]2 cylinders, alternating high and low pressure - "continuous expansion locomotive" (Samuel/Nicholson)[3][*]1 high pressure, 1 low pressure (Mallet-1; Vauclain; Von Borries-1; Lindner; Golsdorf-1; Herdner) [/list] [edit] Three cylinder compound [*]2 high pressure, 1 low pressure (Francis William Webb)[*]1 high pressure, 2 low pressure (Sauvage; Klose; Weyermann; Walter Mackersie Smith; Samuel W. Johnson; Richard Deeley; André Chapelon, Livio Dante Porta) [/list] [edit] Three cylinder triple expansion (projected) [*]1 high pressure, one medium pressure, 1 low pressure (Livio Dante Porta) [/list] [edit] Four cylinder triple expansion compound [*]1 high pressure, 1 intermediate pressure, 2 low pressure (LF Loree) [/list] [edit] Four cylinder compound [*]2 high pressure, 2 low pressure (de Glehn; Barbier; Von Borries-2; Golsdorf-2; Vauclain-1&2, Mallet articulated locomotives) [/list] [edit] Six cylinder compound [*]2 high pressure, 4 low pressure (Chapelon) [/list] These can be staggered with drive to more than one axle, in line concentrated on one axle or in tandem with HP and LP driving a common crank, the latter system being much employed in the U.S.A in the early years of the 20th Century, notably on the Santa Fe.


I never could find a picture or diagram of a cross compound steam locomotive.

For me a lot of the fun about steam locomotives is discovering things like this that I never knew existed.

Jerry


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## rwjenkins (Jan 2, 2008)

In the photo of the Milwaukee 919, at first glance it may look like a simple engine with piston valves, but if you look closer, you see that the rod coming out of what would normally be the valve chest is directly connected to the crosshead rather than any type of valve gear. That's actually the high pressure cylinder, and the larger cylinder below it is the low pressure cylinder. In the Vauclain compound arrangement, both high and low pressure cylinders drive the same crosshead and connecting rod on each side. The valve chest is mounted inboard of the cylinders. Another arrangement was the tandem compound, where each side had a high-pressure cylinder mounted ahead of a low-pressure cylinder, with a single piston rod passing through both. 

Cross-compound engines (with the smaller high-pressure cylinder on one side and the larger low-pressure cylinder on the other) were more rare, and also more difficult to spot in photographs since you typically see only one cylinder at a time. 

Many American railroads tried out several different compound types in the late 19th/early 20th century to try to improve efficiency. In most cases they proved difficult to maintain, and when superheating came along, most railroads opted to go that route instead, often rebuilding the early compounds as superheated simple engines. They seemed to have more success with compounding in Europe though.


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## Pete Thornton (Jan 2, 2008)

Jerry, 

Compound operation was even common on smaller locomotives in the UK, like the "Midland Compound" 4-4-0 #1000: 










Quite a few UK locomotives had cylinders you don't see, between the frames. (Some only had cylinders between the frames!) 

Here's a 4-60 "King" class being lifted onto the frames. You can see the ends of the two inside cylinders: 











US situations, where longer distances resulted in fewer maintenance facilities per mile, meant that external, maintanable, simple running gear was preferred.


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## tacfoley (Jan 3, 2008)

...and don't forget the tiny Kitson-Meyer and Mallet 0-4-4-0 compounds running on narrow gauges in Austria and Germany...two of which are modelled by Regner [and built and run by Rod Blakeman].... 

tac 
www.ovgrs.org


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## david bunn (Jan 4, 2008)

...and don't forget the Great Western Railways compounds from the early 20th Century. 

Bunny


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## rwjenkins (Jan 2, 2008)

The GWR Kings (and Castles and Stars, and LMS Princesses and Duchesses, etc.) were four-cylinder simple engines rather than compounds. The Great Western experimented with a couple of French-built DeGlehn compound Atlantics in the early 1900's that led to the development of the four-cylinder simple 4-6-0's. In fact the first GWR two and four cylinder 4-6-0's ran for a time as 4-4-2's in order to compare their performance more directly with the French-built engines. 

Three-cylinder simple engines were also common in the UK, such as the Gresley Pacifics and their derivatives. There were examples of this arrangement in the US as well, some notable examples include the Union Pacific 4-12-2's, the Baldwin 60000, and the Indiana Harbor Belt 0-8-0's that were the subject of Rivarossi models in O, HO, and N scales. Like the compounds, the center cylinder and crank axle made the 3-cylinder designs more difficult to maintain, so they didn't find widespread acceptance in the US like they did in the UK.


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## Jerry McColgan (Feb 8, 2008)

Unfortunately all photographs are of course two dimensional so the result is that it is difficult or impossible to see and for some of us impossible to imagine those components that we cannot see in a photograph.

Three cylinder engines are a good example of this. Where the heck did they put a third cylinder and how would you run even numbers of wheels with an odd number of cylinders?

Jerry


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## rwjenkins (Jan 2, 2008)

The third cylinder was mounted between the frames driving a crank on one of the driving axles. The wheel cranks (including the inside crank) were set 120-degrees apart instead of the usual 90 degrees for a two (or four) cylinder engine, so you would hear six evenly-spaced exhaust beats per revolution of the wheels.


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## Pete Thornton (Jan 2, 2008)

Three cylinder engines are a good example of this. Where the heck did they put a third cylinder and how would you run even numbers of wheels with an odd number of cylinders? 

Jerry, try imagining a 3-cylinder loco, "Flying Scotsman" in this case, with a third cylinder between the frames but with only 2 sets of valve gear! Sir Nigel Gresley invented his 'conjugated' valve gear which controlled the central cylinder's valves from the actions of the two outside cylinders. 

This web page has a photo (halfway down) of the chassis of a loco with an inside cylinder, clearly showing the crank on the driving axle ( a dummy- it's a museum exhibit):

*Gresley's conjugated valve gear*


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## peter bunce (Dec 29, 2007)

Hi 

The reason for 3 cylinder locomotives was for a more even beat, and that 3 reduced the loco 'nosing' or wiggling from side to side when running. It could also reduce the 'hammer blow' to the track, and compounding was an 'accountants trial ' to try to get more work out of the steam before discharge to the chimney. Four cylinders was a better balance , and used steam better. 

Compounding worked when the proportions of cylinder volumes were correct, BUT required more maintenance; eventually simplicity won the day. 

The LNWR compounds were not generally correct (the 2 4 0 Teutonic class were the best) the Midland (who useed ideas from the North Eastern Railway) got it right - the first locomotives (built by Johnson) were very fast - a speed of 96 mph was recorded with them. Deeley simplified them by making the compounding automatic on starting (Johnson has 3 sets of vale gear, and the crew had to be experts with them) 

Gresley's conjugated valve gear 'derived' the center cylinders action by 2 to 1 levers (at the front of the cylinders) when kept in order (=plenty of labor) it worked well, but the war wrecked the labor market so it was a bit of a liability so it had to go especially on the express locomotives - the valve gear, when running fast 'whipped', or momentarily bent slightly: and therefore gave a false reading to the work required for the center cylinder, which again meant more time in the shops to repair it. 

So simplicity returned again; you in the USA kept the simplicity of 2 cylinders as reduced labor was needed and careful balancing (greater engineering knowledge as time passed) also reduced hammer blow; to the track; factor in diesels, with no hammer blow, and many other reasons shows why the BIG USA locomotives were replaced so quickly. 

But I still like them, knowing (some of) their faults!


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## Dave Meashey (Jan 2, 2008)

This occured to me as I was reading the messages concerning the "hammer blow" from the downstroke of the steam losomotives. It is ironic, but sometimes those "hammer blows" were actually beneficial.

I worked for N&W/NS in the early 1980s. One of my assignments was to write a procedures manual for use with the Plasser Track Geometry Car. I made several trips with that car as part of preparing that manual. I learned an interesting piece of trivia. The mainline was laid with 132lb/yard rail. The company was having a lot of rail failures from the stresses caused by their 100 ton capacity coal hoppers. But the failures were mostly with newer rail! Rail that was laid during the last years of steam operations suffered almost no failures. The analysts concluded that the "hammer blows" from the heavy modern steam locomotives N&W used during the mid-1950s had actually helped to work-harden the rail as though a blacksmith had tempered it.

HMMMmmmmm!

Maybe we could use that to justify more mainline steam excursions. (Wishful, foolish thinking - I know!)

All the best,
David Meashey


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## SteveC (Jan 2, 2008)

Just ran across this and thought it might be of interest, don't know if this is a compound or not but it does show two cylinders outside and inside the frames.



Click above picture to open larger image in separate window.


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## peter bunce (Dec 29, 2007)

Hi Steve, 

That is a straight high pressure steam locomotive, and not a compound. 
It was the first I think to have 4 cylinders - which was in pursuit of a more even loading and hopefully at the same time a reduction in the hammer blow, and 'nosing' that 2 cylinder locos have. That is possibly the reasom for the drawing and article

The railway was a competitor of the Caledonian Railway , and a partner of the Midland Railway, whose Scottish traffic it took North from Carlisle.


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## Jerry McColgan (Feb 8, 2008)

Posted By SteveC on 05 Nov 2009 12:33 AM 
Just ran across this and thought it might be of interest, don't know if this is a compound or not but it does show two cylinders outside and inside the frames.


Hi Steve,

Even if it is not a compound the picture does make it a lot clearer regarding how the inside cylinders worked. It is hard to imagine how they made those huge axles shaped as a crankshaft.

*If anyone has similar pictures from below the locomotive showing how inside frame and outside frame locomotives are constructed I would like to see them as I have never quite understood the difference.* 

Thanks,

Jerry


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## Pete Thornton (Jan 2, 2008)

It is hard to imagine how they made those huge axles shaped as a crankshaft.
Ah - that one's quite easy to visualize if you follow live steam model practice. 

What you do is take a *solid* axle, cut out the crank sides and drill them, then fit them over the solid axle in the right place. Weld them to the axle, weld another bit of axle in the cranks where the new big end will go, and then cut out the old axle between the cranks!


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## SteveC (Jan 2, 2008)

Hehehe Yes sir Peter, if I had bothered to read the printed word it clearly states that it's a high-pressure locomotive and not a compound.

Anyway if interested here's a copy of the full article in PDF format.

Glasgow & South Western Four-Cylinder
File Type: PDF - File Size: 1.5MB
Left-click to open / Right-click to download[/b]


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## Jerry McColgan (Feb 8, 2008)

Posted By Pete Thornton on 05 Nov 2009 10:20 AM 
What you do is take a *solid* axle, cut out the crank sides and drill them, then fit them over the solid axle in the right place. Weld them to the axle, weld another bit of axle in the cranks where the new big end will go, and then cut out the old axle between the cranks! 

I have always had a lot of respect for welders who can accomplish something like that. It never occurred to me that it could be done that way.

Jerry


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## Torby (Jan 2, 2008)

Haven't heard of this in a loco, but many steam tractors are compound engines with 2 cylinders mounted end to end.


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## peter bunce (Dec 29, 2007)

Hi Torby, 

'tandem compounds' with the high pressure cylinderr in front of the low pressure one - they were complicated, the valve gear especially so! 

Built in 1892, and one was #515 and there was another one as well. They also had the then new Belpaire Firebox as well.. 

They had an apparently huge cylinder each side but this was the two together, Baldwin of course had their patented Vauclain version of one on top of the other. 

The Sabnta Fe also has some from 1898, (2 10 2's) and these were when built the most powerful locos in the worls. 

Other American loco works also built locos with this form of cylinders


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## Pete Thornton (Jan 2, 2008)

never occurred to me that it could be done that way. 
Jerry, 
I have to confess that I have no idea whether they make the really big ones that way. But it is easy to visualize, and the modellers often use silver soldering rather than welding. 

I think some are large castings - I know the auto guys cast automobile crankshafts with the cranks, then they machine the bosses and bearings on special lathes.


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## livesteam5629 (Jan 2, 2008)

I heard and witnessed the running of a UP 4-12-2 three cylinder compound once. It was the largest ridged wheel base steam locomotive in the U.S. Maiinly ran in western Nebraska to CA. Had a very distinct sound. Google Union Pacific Steam 4-12-2. Some photos and a recording. 
Noel


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## SteveC (Jan 2, 2008)

Jerry, et al;

Thought you might find the following book on compound locomotives of interest. The link below is to a copy of the book in PDF format that you can read online and/or download a copy of.

The Compound Locomotive:
Supplement to The Science Of Railways
1899[/b] 

And another, British perspective

Compound Locomotives & Superheated[/b]


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## Jerry McColgan (Feb 8, 2008)

Thanks for the additional links and information.

Jerry


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## IllinoisCentral (Jan 2, 2008)

Before it was electrified, the South Side Rapid Transit Company (now the Chicago Transit Authority's Green Line) had an entire fleet of Baldwin compound forneys in the 1890's. 

There's additional information about the line and the locomotives here: http://www.discoverlivesteam.com/magazine/42/index.html


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## Jerry McColgan (Feb 8, 2008)

Posted By IllinoisCentral on 08 Nov 2009 06:23 PM 
Before it was electrified, the South Side Rapid Transit Company (now the Chicago Transit Authority's Green Line) had an entire fleet of Baldwin compound forneys in the 1890's. 

There's additional information about the line and the locomotives here: http://www.discoverlivesteam.com/magazine/42/index.html 

It was that photo of the Forney pulling those coaches in Chicago (I am from Chicago and I used to ride the CTA every day) that resulted in my purchasing the first LGB Forney.

Jerry


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## LogSkidder01 (Jul 30, 2009)

With all the references, I am surprised that Baldwin 60 000 was not identified. Many links are usually listed when searching for three cylinder locs on the web. 

http://en.wikipedia.org/wiki/Baldwin_60000 

A copy of "THE BALDWIN LOCOMOTIVE WORKS, PHILADELPHIA, PA., U. S. A., LOCOMOTIVE NUMBER 60,000, AN EXPERIMENTAL LOCOMOTIVE" can be found at http://www.cwrr.com/Lounge/Reference/baldwin/baldwin.html. The 1929 report contains a section on design and construction that includes some great pictures and drawings. Anyone want to try and model the cylinder casting: http://www.cwrr.com/Lounge/Reference/baldwin/fig7.jpg? 

If you visit Philadelphia you can check out 60000 at the Franklin Institute: http://www2.fi.edu/.


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