QUOTE: Originally posted by choochoo30084 Some railroads used Mountain locomatives 4-8-2 and others used Berkshire locomotives 2-8-4. What was the advantage of either wheel arrangement?
QUOTE: Originally posted by eastside This was because most RR engineering departments didn't bother to study or didn't understand horsepower curves.
QUOTE: Originally posted by jimrice4449 While some RRs did real well w/ Berkshires (NKP pops instantly to mind) the PRR and the NYC EACH had more frt Mountains than the total # of Berkshires on ALL RRs
Paul Keifer, NYC chief engineer, was the reason and power behind the construction of P&LE A-2a #9400-9406 that were not wanted by P&LE veep Curtis Yohe or his railroad. They wanted to dieselize. See Jack Polaritz's book P&LE's Berkshires, Kahndog Pub. 2004. A very interesting, for myself, story and a thoroughly researched piece of work. The condensed version is in Classic Trains magazine, Spring, 2004 issue. Mark Reever
It's important to understand the 4-8-2 and 2-8-4 were from two different generations of steam engines, even though they were only about 10-15 years apart.
The 4-8-2 as noted was created as a bigger Pacific by the B&O IIRC, to haul passenger trains using the 'heavyweight' steel passenger cars being built in the early 20th century. They were particularly needed on mountains and steep grades that the 4-6-2 couldn't handle, except with the older wooden cars.
Note that like the 4-8-2, all the bigger engines from 1900 to the USRA era (2-8-2, 4-6-2, 2-6-6-2, 2-8-8-2) also had 2 wheel trailing trucks. In the mid-1920's, the "Super Power" era emerged with the development of the four wheel trailing truck. Now steam engines could have much larger fireboxes, developing more steam / more power. The 4-6-2 became the 4-6-4, the 4-8-2 became the 4-8-4, and the 2-8-2 became the 2-8-4. As noted, the first ones were used by B&A over their tough grades over the Berkshires. Later Berks had larger wheels, and were used for flatland high speed freights.
BTW strictly speaking, NYC didn't own any 2-8-4s, but the B&A and P&LE were NYC subsidiaries (but B&A steam engines were lettered "Boston and Albany" not "New York Central System" like the P&LE engines).
wjstixThe 4-8-2 as noted was created as a bigger Pacific by the B&O IIRC, to haul passenger trains using the 'heavyweight' steel passenger cars being built in the early 20th century.
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Does anyone out there know if those over fire jets installed in the P&LE Berkshires were successful? Was combustion enhanced?
MiningmanDoes anyone out there know if those over fire jets installed in the P&LE Berkshires were successful? Was combustion enhanced?
I think the answer is firmly in the 'kinda sorta' category.
If you mean 'did the jets provide a proper admixture of secondary air', then probably no. Compressed-air jets chill combustion, and non-preheated air carried along by steam jets has similar effect. In my opinion the same simple-minded "logic" that thought a couple of drop plugs would relieve the explosion hazard from an overheated SuperPower-size crown also thought there would be full and effective turbulent mixing of the introduced secondary air, without screwing up the kinetics of the evolving combustion plume.
My general understanding of guns was that they were useful for smoke abatement when that was desired. The Snyder preheater (which was essentially a circuit of tube with exhaust steam inside) apparently gave far better and more consistent results where actual enhancement of combustion efficiency measured as better Rankine-cycle efficiency is concerned. That isn't to say that introducing 'correct' secondary air isn't a laudable thing -- it is. But it is also difficult to accomplish correctly...
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New York Central had a lot of engines with the "overfire" jets. Some had the small air tanks on the outside of the firebox - others they appear to be "air bleeds."
Looking at easy to examine 4-8-2 "Mohawk" NYC 3001 surviving in Elkhart, Indiana the outside firebox jacket is removed and the "air jets" or "air bleeds are quite visable going into the furnace.
Reading the NYC "Locomotive Fireman's Course of Instruction" found on he Pennsy T-1 site or Richard Leonards Steam Locomotive Archive web page - in this WW II railroad publication - contains how to fire with the "overfire jets" or "smoke abatement jets" - plus one additonal important useage of these!
They helped the NYC fireman judge how thick his firebed of burning coals was! - Yah 6-8 inches measured from the "overfire jets" for a good fire depth! Just brave the heat and look into the fire! Check for klinkers too! Don't shake her down too thin - or you'll have holes in the fire and will piss off the engineer!
Doc
The Virginian RR used them extensively for coal hauling from Victoria, VA (VGN crew change point east of Roanoke) to Sewells Pt. docks in Norfolk (bringing empties back to Victoria, where 2-6-6-6's hauled them back to Roanoke).
The Berkshire 2-8-4 type has a great story -
At the end of WW I the United States Governnent gave up the contol it had taken over the nations railroads. The United States Railway Administration presence remained only in the "USRA type" steam locomotives it had required to be built during the war.
At this time the New York Central Railroad was developing its high speed fast merchandise freight service from Chicago to New York and return using the Mountain 4-8-2 type steam locomotive which they called the "Mohawk" after the Mohwak River valley in New York State.
This developmetn of New York Central high speed freight service, however, caused huge traffic backups on local branch lines. More freight power was needed and the Central was approached by LIMA locomotive works for a promised improvement in its 2-8-2 "Mikado" type of freight locomotives.
Under the LIMA leadership of William Woodward the NYC developed a series of improved 2-8-2 freight locomotive designs each out performing the one previous to it culminating in the development of H-10 design. This design featured 4,500 feet of evaporative boiler surface with 1780 foot of superheater surface and 66 square feet of grate area.
This allowed the H-10 move at fairly high freight speed of 35 mph improving the 20 mph performance of its predecessors, helping elimiate the NYC branch line traffic backup. The little 2-8-2 "Mikado" H-10 powerhouse was equipped with a state of the art ELESCO "closed type" feed water system and a starting tractive effort improving trailing truck booster engine.
Because of the outstanding success which LIMA Locomotive Works was having with the H-10a and H-10b "MIkado" designs the builder had given name to its new ideas - the "Super Power" concept of steam locomotive design.
At this time of success, LIMA came to the New York Central with another new concept locomotive design improvement of the 2-8-2 "Mikado" called the A-1. For the "Steak Sauce" on rails we would all come to know as the 2-8-4 "Berkshire." It was a carry over from the 2-8-2 design - and the new A-1 featured the same ELESCO feed water system, outside dry pipe, front end throttle, all radical changes and added to them a firebox with a large increase in grate area and resultant change to a 4 wheel locomotive trailer truck. The 2-8-4 was born.
Both 2-8-2 and 2-8-4 designs both used the same 63" drive wheels, and 28x30 cylinders. Weight on the drivers was increased from 245,500 for the H-1 to 248,200 for the A-1 about a 1% increase. The A-1 also developed about 9% more tractive effort and had a very similar steam consumption. The A-1 boiler featured 11% more evaporative area, and 18% more superheater surface and again the greatest increse was the 50% addition to grate area and the required four wheel trailer truck.
Road tests of the new A-1 demonstrator locomotive were performed on the Boston & Albany RR - a subsiduary of the New York Central - and were very successful showing a superior ability to handle freight train movements through the Berkshire Hills territory of Massachusets. After testing the B&A bought 45 copies of the A-1 demonstrator locomotive on the spot giving their name to the A-1 type freight super hauler 2-8-4 as the "Berkshire."
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And here is the famous story - "The A-1 was shipped "dead" to the New York Central Selkirk shops for testing between Selkirk, New York and Washington, Massachusets. The A-1 was set up for locomotive testing with full engineering apparatus for dynometer tests with engineers the locomotive and test cars. The locomotive test was performed on April 13th 1925.
To start a regular freight train pulled by a NYC 2-8-2 Mikado H-10 left eastbound with 46 cars weighing 1691 tons. About 45 minutes after the test locomotive - the first A-1 2-8-4 "Berkshire" ever built left eastbound following and behind the H-10 locomotive and train.
From the start of the test, the A-1 "Berkshire" with its train began gaining on the H-10 "Mikado" and its train. At Chatam, New York the two were side by side going east on parallel tracks. Twenty miles east from this point the A-1 "Berkshire" and train was ten minutes ahead of the H-10 "Mikado" and train. Everyone performing the test was shocked by the fantastic performance to say the least."
The "Berkshire" 2-8-4 had handled 26% more tonage, and taken 57 less minutes of travel time to North Adams Junction. The resultant engineering tests showed the "Berkshire" had an average boiler efficiency of 80.5% and a maximum drawbar horsepower of 3890. Water usage rate was 20 lbs per horsepower and coal rate was 2.44 lbs per horsepower - both new records for locomotive efficiency. And a new standard had been set for locomotive builders. Only the speed of the train had been limited by the size of the 63" drive wheels to about 40 mph.
American Locomotive Company saw the handwriting on the wall! It followed the test of the LIMA "Berkshire," and within a month American Locomotive Company ALCO also produced another of its New York Central "Mohawk" aka "Mountain" 4-8-2 engines - the L2 - NYC 2700. Equipped 69" driving wheels the new L-2 went through similar testing procdure developing its power at the 45-50 mph speed range. New York Central was impressed and continued its use of the 4-8-2 "Mountain" aka "Mohawk" ordering another 300 similar L-2 locomotives from ALCO.
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The "Berkshire" 2-8-4 was born from the "Mikado" 2-8-2 for high power freight use but on New York Central fast freight was still the domain of the 4-8-2 "Mountain" aka "Mohawk" developed from the 4-6-2 "Pacific." Which is a different story.
Yet another very enjoyable soliloquy from The Bard of The High Iron!
Thanks for a fun read, Dr. D!
The contenders on NYC...
H10b Mikado...
Lima A-1 (Soon to be Berkshire)...
The NYC Fast Freight Victor - L2 Mohawk...
But there is more. This is just the railfans' "conventional wisdom" part. We take it one step further -- a very logical step further -- with the understanding that quite a bit of power was 'left on the table' with the A1 design; it could easily accommodate another driver axle's worth of adhesion, and T&P promptly gave it that. Remember the comment about lateral balance problems with high piston thrust driving symmetrically on a middle driver? And really poor chassis control with the articulated trailing truck? Those engines had both in spades...
NOW along comes the thing that saved the Berkshire ... the Erie, and the AMC. They do it by putting ... higher wheels, and a better leading truck design, and probably better equalization, on the engine, so it becomes not just an engine that makes horsepower at 40 mph but one that can actually run that fast without ruining track or trainmen's vertebrae. And adding another axle to this design allows scaling everything up 5/4 - producing the C&O T, and by extension the PRR J1 which rather promptly got its drivers increased to 70" ... but I get ahead of the story slightly.
By the time Eksergian publishes on balancing, in 1928, wise people are figuring out that the right combination of approaches can be used to build a faster locomotive, not just a more fuel- and water-efficient one. (Would that the people who led up to the ACL R-class fiasco thought more about this and less about following standards bodies making dumb mistakes ... but again I'm getting ahead of the story, and onto a parallel one of different import for later.)
It becomes cost-effective to retrofit a comparatively small set of parts onto a waddling monstrosity -- a disc main driver with better balancing, lightweight rods, etc. And this turns the T&P dogs into quite good locomotives, as Trains Magazine commented when they reported on testing 610 with a then-modern dynamometer car sometime in the '70s (it's in that free package of online articles for those who are interested), even without fixing that articulated trailing-truck thing.
THIS is the evolutionary line that produced the famous Nickel Plate fast-freight engines ... but there is another step to this, which is what happens in practice when you want one-and-a-half Berks instead of 5/4 of one. You put a hinge in it.
Baldwin appears to be the first company that 'gets' the general idea of a high-speed simple articulated, but their initial attempts were just one-and-a-half Mikes. On the other hand (to their credit, imho) they pretty quickly figured out the 2-6-6-4 as a high-speed configuration that got the business done wherever it was tried and used right (in all too few places!) Then the N&W gets hold of it and ... does their contemporary spectacular job of conceptual and then detail design, admittedly with a few comical teething troubles with things like 'unraveling' valve gear and weird roller-bearing axle bending. Now we have a true high-speed articulated locomotive, and Lima takes this to its logical conclusion -- albeit with an awful lot of weight, and an awful lot of extra complexity, but with the interesting idea that a one-and-a-half Berks design might be able to produce considerably more usable power than one and a half actual Berkshires, even with the shorter coupled wheelbases and relatively 'unloaded' forward engine...
(Note how different the various flavors of Challenger are from this evolutionary line. Those have four-wheel leading trucks, which I would argue are relatively wasted compared to what a good two-wheel design can do on a Mallet-style articulated front engine, but they carry their fireboxes high out of necessity and give up a considerable amount of effective radiant heating surface and vertical circulation in so doing. That works well when you need beaucoodles of grate area for burning weird subbituminous "coal", but is a poor substitute for a deep firebox with a good double-Belpaire chamber...
Alfred Bruce loved to take credit for 'solving' the issue of front-engine stability in high-speed articulateds, but it ought to be remembered that the N&W A class did essentially the same thing with the forward slide plate and equalization, years before even the first series of Challengers, so I'm not as impressed with Alco innovation there as I was intended to be...)
Yep, no-one called them "The Weary Erie" after those Berkshires showed up.
No seriously anyway.
Really good stuff, Mr. Wizlish! I am going to see if I can get these in order of discussion.
Berkshire with an added axle - Texas & Pacific 615...
Erie No Longer Weary Berkshire ...
More Of A Good Thing (Driver Axles, That Is) at C&O - A Texas in Ohio...
Imitation Is The Sincerest Form Of Flattery - Pennsylvania J - Speedy Flatland Hauler and Altoona Mountain Mauler...
Nickel Plate Perfection - State of the Art Berkshire...
I'll See Your 4 Driver Axles and Raise You 2 - Pittsburgh & West Virginia 2-6-6-4...
"Double Pacific" Seaboard Airline Fast Freighter 2-6-6-4...
Triple Threat - Maximum Tonnage, Fast Freight Manifest, and Varnish -
The Magnificent A...
Minneapolis & St. Louis was all set to order a small batch of 2-6-6-4's similar to SAL's design but that was vetoed by the War Production Board. M&StL wound up getting A-B-A sets of FT's, a much better choice in the long run.
wjstix It's important to understand the 4-8-2 and 2-8-4 were from two different generations of steam engines, even though they were only about 10-15 years apart. The 4-8-2 as noted was created as a bigger Pacific by the B&O IIRC, to haul passenger trains using the 'heavyweight' steel passenger cars being built in the early 20th century. They were particularly needed on mountains and steep grades that the 4-6-2 couldn't handle, except with the older wooden cars. Note that like the 4-8-2, all the bigger engines from 1900 to the USRA era (2-8-2, 4-6-2, 2-6-6-2, 2-8-8-2) also had 2 wheel trailing trucks. In the mid-1920's, the "Super Power" era emerged with the development of the four wheel trailing truck. Now steam engines could have much larger fireboxes, developing more steam / more power. The 4-6-2 became the 4-6-4, the 4-8-2 became the 4-8-4, and the 2-8-2 became the 2-8-4. As noted, the first ones were used by B&A over their tough grades over the Berkshires. Later Berks had larger wheels, and were used for flatland high speed freights. BTW strictly speaking, NYC didn't own any 2-8-4s, but the B&A and P&LE were NYC subsidiaries (but B&A steam engines were lettered "Boston and Albany" not "New York Central System" like the P&LE engines).
Toronto, Hamilton & Buffalo 2-8-4 - nice looking unit!
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