Just how "good," were Articulated Locomotives as Steam Locomotives?

I assume that this is based on a lack of understanding of the tractive effort and adhesive weight necessary for operation on severe gradients. A "super power" locomotive is of no use if it does not have the required tractive effort or adhesive weight to lay down that power, although the inquirer might be thinking of using super power locomotives in multiple instead of articulateds? Let the fun begin........

Naturally, some articulated steam locomotives were more successful than others. Articulated steam locomotives had an advantage over non-articulated "single" steam locomotives for certain types of service. In a way, one can think of articulated steam locomotives a two locomotives spliced together. Thus, a single crew can operate "two locomotives simultaneously" with articulation. A railroad could double head steam locomotives to haul the approximate amount that a single articulated could.  However, each steam locomotive in a double headed configuration would require it's own crew; thus, two crews would be required for double heading whereas just one crew for an articulated locomotives. Furthermore, there are certain skills required of the crews for double heading and as such they would be top of the line experienced crews which means top of the line in terms of wages. In the end, articulation reduced overall costs for certain types of train operation.

In US and Canada North American operations the Mallet type articulation where supporting the front of the locomotive on a bogie frame was the most successful type of articulation. However, around the world the Beyer Garratt design was the most successful as it was more stable around tighter curves. 

Dont forget that these locomotives were designed for the terrain that they would travel on,the greatest example the N & W  Y6B small diameter drive wheels for hauling coal drags in the Appelatian Mountains.

Mikey

mikey posted:

Dont forget that these locomotives were designed for the terrain that they would travel on,the greatest example the N & W  Y6B small diameter drive wheels for hauling coal drags in the Appelatian Mountains.

Mikey

Thats right, the N&W used both; articulateds (Y class/ A class) for freight hauling, while the famous 4-8-4 "J" was mainly for passenger service. Different types for different jobs.

Honestly, that's a fair question that goes beyond Super Power vs Articulated steam designs. A very basic and incomplete "super power" definition is here. https://en.wikipedia.org/wiki/Superpower_steam

You have to realize that there were super power designs that were also articulateds. The C&O and N&W both clung to super power designs while most of the rest of the railroad industry went with diesels. The C&O ran Kanawha's (2-8-4s) , Greenbriars (4-8-4s), and Alleghenys (2-6-6-6s) that were all "classic" Lima products. The N&W built their own in Roanoke (Class Js and As). They were used in the mountains too. In general, super power designs made much more steam than older steam loco designs like the USRA engines and other engines from the teens and 20s. Super power based steam engines represent the best of steam designs. But you also have to look at what speed steam horsepower peaked vs the speed the trains could run, given the railroads profile. Engine weight & driver diameter contributed to how slippery the engine was. Some were more successful than others. 

How fast do you need to go? How slow do you need to go. Are you on a grade or in the flat-lands? Merchandise, drags, or passenger trains? Are you using the engines primarily as helpers? Those factors were all considerations when a railroad went a builder for new power.

But I would think the Garrett arrangement would lose traction effort as time went on because it was a huge "tank engine".  As fuel and water were used, the locomotive would weigh less.  It would be like taking the weights out of our model locomotives.

This is actually a good question....if you're a Santa Fe guy.  OTOH, this thread could go in a million different directions, so let's see what develops.   Keeping popcorn and flame suit close by !

How good were they is a good question.    They were obviously good enough that most users  continued to use them to the end of steam.     Other RRs experimented and then passed.    the PRR for example had at least a dozen articulated before WW I.    With the freight cars of the era, they found that the articulateds were pulling drawbars out of cars and breaking trains.    They could not use the available power/tractive force, so they went to using more helpers pushing.

Articulateds logically required more maintenance than simple engines.    With basically 2 steam locos together, it stands to reason.     However, the cost must have been justified in most cases vs using two simple engines double headed.  

Articulateds had the advantages of much more tractive force on one locomotive, and shorter ridgid wheel bases to handle sharper curves easier.     These are big advantages for mountain RRs.

If articulateds weren't "better" than non-articulated locomotives, the Norfolk and Western wouldn't have designed and built so many of them.  Notice the N&W had exactly zero 2-8-2's, 2-8-4's, 2-10-2's or 2-10-4's.

Rusty

This should tell you what you want to know:

http://www.steamlocomotive.com/allegheny/

It explains why C&O replaced the 'Texas' 2-10-4's with the articulated Allegheny.

Bessemersam --- Thanks for asking this question

As a postwar diesel guy I just always threw a blanket over ALL big steam ---- threads like this help me learn a little more

I try to ignore some of the "experts" here --- I'd love to drill them on some of the things they DON'T know but ---Like my mother use to say "If you don't have anything nice to say ..."

Thx again

  Millennials really don't know how to research subjects such as this. They eschew printed materials or don't believe them; there is a huge difference in how I researched term papers in 1977 as compared to today.
This was left over from the GG1 thread...

George S posted:

This should tell you what you want to know:

http://www.steamlocomotive.com/allegheny/

It explains why C&O replaced the 'Texas' 2-10-4's with the articulated Allegheny.

 

 

George,
First of all, while that web site is convenient, there are better sources of serious knowledge out there. I'm going to disagree with you about 2-10-4's. If you can find a copy of "The Chesapeake & Ohio Class T-1 2-10-4 Steam Locomotive" by Thomas Dixon & Eugene Huddleston, I would suggest that you pick it up. It seems that the T-1 was much preferred over the H-8 by many engineers. 

You also must remember that the C&O decided to dieselize in the late '40s. Steam was on the way out, engines got moved from one area to another with some T-1's heading to the tidewater area of Va. The last of which were retired in 1953.

Everyone has different tastes. Mine prefer the handsome looks of the 2-10-4 T-1 over the pipe fitter's nightmare looking 2-6-6-6 H-8.

Big Jim posted:

George S posted:

This should tell you what you want to know:

http://www.steamlocomotive.com/allegheny/

It explains why C&O replaced the 'Texas' 2-10-4's with the articulated Allegheny.

 

 

George,
First of all, while that web site is convenient, there are better sources of serious knowledge out there. I'm going to disagree with you about 2-10-4's. If you can find a copy of "The Chesapeake & Ohio Class T-1 2-10-4 Steam Locomotive" by Thomas Dixon & Eugene Huddleston, I would suggest that you pick it up. It seems that the T-1 was much preferred over the H-8 by many engineers. 

You also must remember that the C&O decided to dieselize in the late '40s. Steam was on the way out, engines got moved from one area to another with some T-1's heading to the tidewater area of Va. The last of which were retired in 1953.

Everyone has different tastes. Mine prefer the handsome looks of the 2-10-4 T-1 over the pipe fitter's nightmare looking 2-6-6-6 H-8.

We were talking about power, not looks or preferences.  The article has the power and traction specs.  Certainly, I am aware there are many sources of information. Anyone can search or read more books.  I don't think what I posted required such a pompous response.  

George S posted:

Big Jim posted:

George S posted:

This should tell you what you want to know:

http://www.steamlocomotive.com/allegheny/

It explains why C&O replaced the 'Texas' 2-10-4's with the articulated Allegheny.

 

 

George,
First of all, while that web site is convenient, there are better sources of serious knowledge out there. I'm going to disagree with you about 2-10-4's. If you can find a copy of "The Chesapeake & Ohio Class T-1 2-10-4 Steam Locomotive" by Thomas Dixon & Eugene Huddleston, I would suggest that you pick it up. It seems that the T-1 was much preferred over the H-8 by many engineers. 

You also must remember that the C&O decided to dieselize in the late '40s. Steam was on the way out, engines got moved from one area to another with some T-1's heading to the tidewater area of Va. The last of which were retired in 1953.

Everyone has different tastes. Mine prefer the handsome looks of the 2-10-4 T-1 over the pipe fitter's nightmare looking 2-6-6-6 H-8.

We were talking about power, not looks or preferences.  The article has the power and traction specs.  Certainly, I am aware there are many sources of information. Anyone can search or read more books.  I don't think what I posted required such a pompous response.  

It wasn't pompous by any means. I'm sorry you couldn't see it for what it is, just a different point of view.

The whole articulated idea goes back to Anatole Mallet and the locomotive designs he worked on in Switzerland. His earlier experiments were with compound steam engines. From that he developed the compounding into a locomotive with a rigid rear frame running on boiler pressure, and an articulated front frame running on the low pressure exhaust steam with the larger cylinders. The original front articulated frames were known as Bissell trucks, with the pivot point behind the frame. The compounding and articulation gave a more steam-efficient, more powerful and more flexible locomotive, especially for winding mountain railways and lightly-laid lines. Trying the same power on multiple driving wheels in a rigid frame would run into trouble on this type of rail line.

By the time articulated engines fully evolved in America, the pivot-point arrangement had changed a bit, and the huge low-pressure front cylinders were becoming a liability in tracking and speed limitations because of all the reciprocating loads flying around. The American designs went to high-pressure all round on the articulated frames, but you still had flexible, powerful locomotives. That principle dictated where and how they were used, not really that they were better or worse than rigid-framed engines.

The Clinchfield Ry [CC&O]made wide use of both "Early Challengers" from the 1930s and the "Wartime" Defense Dept Challengers that it purchased postwar and modified for its mountain railroad running down the spine of the Applachains. Long coal drags and and seasonally long reefer trains northbound with fruit.

Firewood posted:

By the time articulated engines fully evolved in America, the pivot-point arrangement had changed a bit, and the huge low-pressure front cylinders were becoming a liability in tracking and speed limitations because of all the reciprocating loads flying around. 

Well, try telling that to the N&W, who believed in and kept on developing the 2-8-8-2 articulated compound locomotive into an engine that could run with the best of them. Don't believe all of this slow-poke mumbo jumbo that you read everywhere. The Y6 class, while its main purpose was hauling heavy tonnage, could indeed roll 'em on level ground. The huge low pressure cylinders were no more a liability in its intended environment than any other engine. As a former Shenandoah Valley Y6 engineer told me, "63 mph was about as fast as you wanted to run one. After that things started getting a little shakey." Ed King has mentioned stories of 70 mph on the Bristol line. 

The Southern Pacific's Cab Forward design was very successful and the railroad had hundreds of them.  They were designed for the mountains but were used throughout the system to haul all kinds of trains including passenger trains.

NH Joe

The line that logged off the Smokies used as its prime engine an articulated, that then went to the northwest for further logging.  Several logging roads used articulateds.  Many of these roads were low-budget, with rickety, transient trackwork, and not disposed to frivolous expenditures on equipment that did not give the most bang for the buck.  The Class 1's that used them had plenty of nickel-squeezers in their accounting departments, with stockholders to worry about, and were also disposed toward maximum efficiency.

Big Jim posted:

Firewood posted:

By the time articulated engines fully evolved in America, the pivot-point arrangement had changed a bit, and the huge low-pressure front cylinders were becoming a liability in tracking and speed limitations because of all the reciprocating loads flying around. 

Well, try telling that to the N&W, who believed in and kept on developing the 2-8-8-2 articulated compound locomotive into an engine that could run with the best of them. Don't believe all of this slow-poke mumbo jumbo that you read everywhere. The Y6 class, while its main purpose was hauling heavy tonnage, could indeed roll 'em on level ground. The huge low pressure cylinders were no more a liability in its intended environment than any other engine. As a former Shenandoah Valley Y6 engineer told me, "63 mph was about as fast as you wanted to run one. After that things started getting a little shakey." Ed King has mentioned stories of 70 mph on the Bristol line. 

Thanks for that info Jim! Appreciate it.

Articulated steam locomotives were "successful" because they allowed the pursuit of maximum power in one locomotive. Very few 2 cylinder locomotives came close to the horsepower production of the big articulateds - 2 examples would be the ATSF 2-10-4 and the C&O/PRR 2-10-4. Large articulateds allowed the creation of huge boilers and huge fireboxes which produced great quantities of steam, which produced high horsepower. The aforementioned 2-10-4's had 122 sq. ft fireboxes, Big Boy had 150 sq. ft......the 2-10-4's produced approximately 6000 horsepower, Big Boy, 7000. Successful?  Big Boys remained in service two years longer.

I would say they were pretty successful. 

Some good info here.  And some passionate opinions

Oh, the joys of big steam !  An awful lot of this came down to who was the chief mechanical officer / motive power superintendent at any given time.  It's hard to separate the men from their machines.  C&O and U.P. are some great examples.  The Lima / AMC Allegheny was so over the top because those making the decisions wanted them that way. In the end, it backfired, and Lima got sued over the excesses.  U.P. was going to have the "BOY"....and the bigger, the better! It was a page right out of the Jabbelmann / Jeffers playbook ! These two bred Art Stoddard and Dave Neuhart, and big got even bigger !   N&W steam is big, but not really that big.  Powerful?  Economical?  Probably the best overall family ever built !

The large fireboxes and boilers were important for providing sufficient volumes of steam at speed (very large volumes of steam were passed through the four cylinders of a simple articulated); the actual horsepower available depended upon variables such as boiler pressure, degree of superheat, driver diameter, and so on.

Some issues with the info that is out there:

1.  Just because it is on the Net, it does make it true.

2.  Many of the books with good info are either out of print, very expensive, or both.

3.  Books needed for reference on this subject are not going to be found in today's public libraries.  At least not in Houston.

While I love the big articulated loco's for all the reasons already mentioned,  don't count out the large garratt engines from the SAR.  Very flexible wheel base by mounting the boiler package on a central skid, still one crew for two engine's worth of power, and no need to turn them around.   And yes they did lose tractive efforrt as the water and fuel was consumed

Without taking anything away from the 611 , but isn't the "A" pretty much about as good as it gets when it comes to steam power ?  

A loco that can pull heavy freight drags, or run at a good clip with a faster passenger train if need be. Kind of a best of both worlds?

Big Jim?

Challengers of the UP and D&RGW could and did the same!

Another measure of articulated steam locomotive's success is that the last main line steam locomotives in service in the USA were articulateds: N&W Y6b's and DM&IR 2-8-8-4's (May 1960 and May/June 1960, respectively).

True, but the A 's tractive effort is rated at over 25,000 lbs greater, yet it was 120,000 lbs lighter.

mark s posted:

Challengers of the UP and D&RGW could and did the same!

Another measure of articulated steam locomotive's success is that the last main line steam locomotives in service in the USA were articulateds: N&W Y6b's and DM&IR 2-8-8-4's (May 1960 and May/June 1960, respectively).

This engine might get an *, but UP 844 has never been retired!

RickO posted:

Without taking anything away from the 611 , but isn't the "A" pretty much about as good as it gets when it comes to steam power ?  

A loco that can pull heavy freight drags, or run at a good clip with a faster passenger train if need be. Kind of a best of both worlds?

Big Jim?

I can't argue with that. Another man I worked with said that he was travelling down Rt. 460 in eastern Va. on his motorcycle running 80 mph when a "twelve hunerd" passed him like he was standing still!
A man that I worked with that fired on the Norfolk Div. said he had a twelve hunerd on a 40 car troop train and they took it over the top of Blue Ridge at 50 mph with the safety valve popping off.
Then the folks at the C&O specifically wanted an engine that would be more powerful than the Class A...and Lima gave them the H-8. That seems to me to be a complement in itself!

So, "JUST HOW "GOOD" WERE ARTICULATED LOCOMOTIVES AS STEAM LOCOMOTIVES?" 
On the N&W, they were real good!!!

For your information, the following is a quote from "The Allegheny Lima's Finest" by Gene Huddleston and Tom Dixon:

"An announcement in Railway Age Gazette, dated April 5, 1912, heralded the change from the 2-8-0's to the 2-6-6-2's: 'Twenty-five Mallets (classes H-1 and H-2) replaced forty-four Consolidations on the Allegheny climb, and the number of trains was reduced by seventeen. With Consolidations, forty-one trains were run daily; with the Mallets twenty-four. Consolidations has Consolidation pushers from Roncevete to Allegheny with 2,250 tons, and average speed was seventeen m.p.h. The new Mallets handled 3,200 tons without a helper."

Take note that eight driven axles were replaced by six.

Head on out to Western Maryland this July and see for yourself!

I think to simplify, how well articulated steam locomotives were "good"

depended on how well they fit the railroad they were designed to

work upon.

Ed

Yes the issue of all research is this essential question; is the information accurate?

For what it's worth, I can only recall two railroads major railroads that had unsuccessful experiences with articulated steam locomotives:

1) The AT&SF tried those drastically unsuccessful 2-10-10-2 locomotives, in the early 1900s. They didn't last very long and by the mid 1900s (1912?) the AT&SF gave up on them and made two 2-10-0 locomotives out of the failed attempt at articulateds.  Subsequently, the AT&SF would NEVER even consider the "modern articulated" models such as 2-6-6-4, 4-6-6-4, 2-8-8-4, or 4-8-8-4 designs.

2) The Western Maryland asked Baldwin Locomotive Works, for a simple articulated steam locomotive to replace there massive 2-10-0 locomotives.  Baldwin came up with a 4-6-6-4 wheel arrangement that ALCO had successfully designed & built for the UP, NP, and some other a roads. Once in service, the Baldwins were found to be rough riders, and worse yet,,,,,,would NOT outperform the WM's huge 2-10-0 locomotives! As a result, the Chief Mechanical Officer who was responsible for the design and purchase of the Challengers, took his own life.

To add on to the above observation re Western Maryland's 4-6-6-4, they were acquired to speed up transit of freight, particularly west of Cumberland, MD. That is pretty tough mountain railroading, with 1.75% grades and many curves, and the 4-6-6-4's had the same tractive effort as the Decapods. Due to the mountainous route, the Challengers were unable to get up to speeds where their greater horsepower would come into play. Hence, the investment in motive power did not pay off. The WM was very speed conscious, as their fireball "Fast Freight Line" herald splashed across their tenders, indicated. Speed was a matter of survival, as they competed head on with the Baltimore & Ohio. 

        The WM 4-6-6-4's were probably not bad locomotives, but rather a mis-applied design to operating requirements. Baldwin had experience building successful 4-6-6-4's in 1937-38, as they built the Rio Grande's big 3700's, which handled fast freights and passenger trains (the Scenic Limited) between Grand Junction, CO and Salt Lake City.

       It was said that the Western Maryland would have been better served by a locomotive similar to the B&O's EM1 2-8-8-4, which had lower drivers. A very good write up on the WM Challengers appeared in Trains Magazine, April 1982, by Bert Pennypacker, titled "Challengers over the Alleghenies - the Western Maryland's unappreciated Challenger locomotives".