I love the look of a PRR K4 Pacific. Why are the sides of the firebox flat? Does that type of firebox have a name? What are its advantages?
That firebox, to me, gives the engine a lot of class.
Shocking to me that only two still exist.
Still in training.
It's called a "Belpaire" firebox, designed by a Belgian of the same name. Someone can correct me on this, but I believe the Belpaire firebox was supposed to be easier to build than the more common "radial-stay" firebox and easier to take care of.
It was fairly common in Europe, but only the Pennsylvania railroad and maybe one or two others adopted it in any great numbers, the Pennsy having the most locomotives with the Belpaire 'box.
I agree, that Belpaire firebox is definately one of the things that gives a Pennsy K4 it's massive, no-nonsense good looks!
Yes, it's sad there's only two K4's left, but we're probably lucky to have even them. As we all know, there's no NYC Hudsons left at all.
And easier to maintain and less srain on the staybolts.
A principal point of the Belpaire design is that many of the staybolts can be the same length in the absence of crown bars. This is even more important if your shop uses 'bespoke' staybolt taps that cut both the inner and outer sheet threads 'in sync' -- you need many different such taps for a radial-stay firebox, but 'one size fits all' for Belpaire.
Overmod,
1361 and 3750 are the two lucky K4 survivors although 1361 seems a little worse for the wear. It certainly is a stunning engine to look at with the worlds most haunting whistle.
Its parts are all at Steam Town mostly being cast across the shop floor for more than a decade' And the once famous engine seems foraken by the State of Pennsylvania who by act of the legislature once declared it as "The State Locomotive."
And there is always the danger with a project like this, that parts become lost, scrapped and or stolen if the engine is not eventually reassembled at some point.
If I remember right, I believe the difficulty with the overhaul came in finishing the boiler, particularly the "Belpare firebox" which Pennsyvania RR had mostly worn out by the time the engine was put on display at horseshoe curve.
And the continual cash overuns on the state sponsored overhaul came to an end when the entire backhead of the Belpare firebox needed an additional cash expendature and extensive steel replacement.
According to rumor there was also some concern by modern boiler inspectors about the "Belpare" design ever being a safe one and being properly built and maintained by the railroad. In order to re-certify it would require some engineering changes to qualify it. I heard the steel was not thick enough and there were not enough staybolt supports or something of that nature.
Although my knowledge of this is somewhat limited because the entire overhaul story behind the abandoned project is very difficult to obtain.
Your comments about the "Belpare" being fairly a straight forward design are new to me and I believe my knowledge of the "Belpare firebox" design were that it scared off most railroads from using it.
Pennsy seems to have stuck with it on all locomotives from the 6-8-6 steam turbine to the 4-4-4-4 Duplex engines, and with great consistancy.
Do you have any idea where the "Belpare firebox" issue went south with the inspection and recertification of K4 1361?
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It also seems that someone with some deep pockets should have been able to move this project along and continue the overhaul rather than let the entire engine risk going to scrap. For cryin out loud its only one of the most famous steam locomotives in American History!
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Dr. D
There is a great deal to be said about the 1361 saga, much of which has in fact been said over and over and over. If you are very, very patient you can put most of the current story together from threads on RyPN (but you will have to work for it).
The parts are all carefully accounted for, in the ways that are necessary, and work on the mechanical parts has been progressing slowly and 'as invisibly as possible') for a number of years.
The firebox issue revolves around PRR in a sense 'gaming' the boiler safety regs on this and many other fireboxes in service. The plate thickness even without service wastage was too thin to give suitable factor of safety even at the old 4x without double-nutting some of the staybolts; the issue of more recent concern is that the new (post-part-230 and new-code) factor of safety is 5x. So the issue arises that the 'historic fabric' firebox is hopelessly incompetent even at the lowest restricted pressure that would produce meaningful performance.
Bennett Levin and Wick Moorman are now involved with this and the restoration is going forward with a sensible if more than a little 'black project secrecy' lack of loudmouth promotion. The operational plan is to make a new welded firebox at full dimensions for 5x safety at full rated pressure (205psi IIRC) and meanwhile I presume some of the known wack problems like the hubliner tightness plus skewed tire overheating will be addressed without radical 'intervention'. (It was my understanding, perhaps wrong, that there will be roller-bearing conversion update on engine-truck and KW trailer, but not drivers; some better tribology being applied to plain bearings there).
There is no real 'hurry-up' need to prioritize finishing the engine, and you will note the absence of major fundraising or crowdfunding projects to do so. There are probably deep enough pockets to tap already to finish the work without risk of 'failure' ... but no particular need for the engine to be 'fixed' ASAP, either. If you want to see a complete K4 that will never run again, 3750 is your baby.
One thing I believe we can rely on, if Bennet Levin's involved with the 1361 restoration it WILL get done. And as Overmod implies it won't be done next week, or next month, or next year, but 1361 will see the light of day again.
In the meantime, I'll just run my MTH 1361 if I need a K4 fix!
Thanks for the insight on the K4 story!
It seems a little strange about the Pennsylvania Railroad - here we have the most famous corporate railroad structure known as "THE STANDARD OF THE WORLD" with an unequalled engineering facility available like Altoona shop. So capable as to construct and test steam engines under their own power on the company dynometer then re-engineer needed changes.
An engineering department without equal capable of designing completely new scientific steam designs on the forefront of steam technology - and then redesigning them after creating and testing prototypes such as the 4-4-6-4 and 4-6-4-4.
Also a Public Relations budget so large as to allow the design and construction of The Worlds Fair Locomotive and to have it running and on display before the public! - the unique Raymond Lowey 6-4-4-6 - and to be designing with the help of the Westinghouse corp the equally unique 6-8-6 steam turbine locomotive. So advanced and secret that the WWII US government considered it a National War Secret - and would not allow any filming of the locomotive under power!
We have here a corporate giant - The Pennsylvania Railroad - in the form of the STANDARD RAILROAD OF THE WORLD bringing us from - The age of Industrial Arts - into the Scientific Age of industrial engineering.
"Gaming the safety factor of X4 in firebox design by double nuting the staybolt design of a 200 psi firebox?"
"Using the Belpaire design because it does not require anything but standard stabolt sizes and tooling in its uniquely flat sided simplicity of construction!" Which no other United States railroad would be bothered with such construction except a few Europeans who for some reason also felt it is also a more practical and workable design than the radial stay firebox.
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Possibly the T-1 trust has some insight on re using the Belpaire design in their reconstruction of their replacement T-1 engine?
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Not sure I understood your comment "I presume some of the known wack problems like the hubliner tightness plus skewed tire overheating will be addressed without "radical" intervention."
Well, the PRR called themselves the "Standard Railroad Of The World."
No-one else did.
There are numerous "new boiler" rebuilds out there that are running successfully, with the operative word being running of course. The next one will be the CNW R-2 4-6-0 1385 at the Mid-Continent Railway Museum
Picture here:
https://www.midcontinent.org/category/cnw-1385/
Along with a new tank on the tender, it will be good for many decades to come.
If a new boiler gets 1361 back on the rails under steam at 45 mph, I can surely support that.
Haunting whistle indeed! Here's 1361 on her shakedown "cruise" back in 1987.
https://www.youtube.com/watch?v=mTVjbeRBWWk
Here are some photos of 1361 under steam:
https://www.railpictures.net/photo/697734/
https://www.railpictures.net/photo/659859/
https://www.railpictures.net/photo/658308/
https://www.railpictures.net/photo/646853/
https://www.railpictures.net/photo/629949/
https://www.railpictures.net/photo/576715/
https://www.railpictures.net/photo/107195/
This is the PRR that brought us the L5 electrics, possibly the most incompetent locomotive design in the Western world, after having gotten detail reasonably right on the DD1s. Then trying to design 2-C-2 electrics for Pacific-hauled trains, 2-B-2s for Atlantic-hauled trains, and 1-D-1s for Mikado-hauled trains, and then on the same even-by-then-proving-lacking-at-speed principle expensively build and arrogantly number a 2-D-2 ... something they could not bother to build in steam equivalent ... to try competing with the NIH New Haven underframe and motor tech they couldn't originate, but sure could get restyled. In any kind of modern steam: they flubbed the detail design of the K5 just at the point the rest of the world went to super-power principles; rang just about every wrong chime possible with the Q1; built a fleet of passenger duplexes they couldn't be bothered to train their engineers to run; made up a bunch of magnificent 4-4-6-4s with utterly no place to run postwar; were either too dumb or too cavalier to get properly redlined prints of a borrowed 2-10-4 which then collided with its counterparts a few times on not-quite-expected clearances; did a steam turbine with staggering 130-mile range and then decreased its range in redesign; built another turbine that perhaps holds the world's record for most staybolts torn out without massive explosion ... and you come to me whining about magnificent engineering aplomb? (And I didn't even have to tell any Big Engine or rectifier electric or Centipede stories...)
And remember I'm one of the principal supporters of the promise of a T1 done a bit more correctly and a little less killed off Borgia-style to get out of inconvenient equipment trusts.
The proximate cause of 1361's (fairly abrupt) removal from service was a catastrophic driver-bearing failure. One person involved with the engine said (and this quite recently) that the cause was excessive hubliner friction due to an accidentally-misaligned tire; another notes that the liner in question supposedly ran hot from the day the engine came out of restoration. My suspicion is that it was actually 'both' in a kind of straw-that-broke-the-camel's-back way. The take-home point: Expect either problem NOT to recur after the engine is done this time.
Well I guess that puts the "fat in the fire" concerning the STANDARD RAILROAD OF THE WORLD! At least I now know that GENERAL MOTORS does not stand alone! Hopefully, FORD MOTOR AND UNION PACIFIC will never get there.
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Mind you, I'm not making fun of the whole PRR crew with the advantage of 20/20 hindsight. The picture painted by looking through the surviving material at the Hagley (a good case in point being the response to the 'secret' Baldwin steam-turbine project in the immediate postwar years that would produce those C&O M-1s) shows a side of the people in authority that makes them very human and points up the 'selection process' that brought them to their positions of authority and control in the PRR organization.
There are some fascinating roads not taken. One reason PRR did not jump on Super-Power earlier was that priority in new tech development in the critical period from 1925 to 1927 was on internal combustion of various sizes ... until the person driving that died suddenly, and his successor went back to 'standard' steam in a big way just in time for the Depression to slam the door on anything newer than cutting-edge power for 1923. If you look carefully you'll see PRR doing a great deal of imaginative thinking ... most of which went nowhere, some of which sucked breathtaking amounts of real money (the scam Baldwin pulled on the S1 development almost defying rational description).
Why someone did not actually build a mechanical steam turbine ... or high-speed mechanical passenger unit ... with a Bowes drive in it, I still can't quite figure. Certainly PRR did much more than its fair share in assessing presentation! I think we have to look more carefully at how PRR implicitly followed Sloan's and Dilworth's vision for truer motive-power detail-design 'standardization' on a scale (and with nominal profit margins!) far outside anything PRR could induce on its own.
Flintlock76 As we all know, there's no NYC Hudsons left at all.
Where reality fails, fiction fills in!
https://blerfblog.blogspot.com/2019/12/the-hidden-hudson.html
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Great story in that blogspot! Very clever indeed! If only...
Mind you, in the late steam era the Reading had some outstanding Pacifics, the G3 being the last, and coming out post-war, so they really wouldn't have needed a Hudson, but hey, that's a good story anyway!
Every steam locomotive that I've seen in England (and I have seen many) has a Belpaire firebox.
Nothing inherently wrong with the Belpair. And I like Pennsy power, including the K4. Possibly an aquired taste. As far as I know the K5s were successful, and the only reasons more were not built was electrification drastically reducing the need for new steam power, and, earlier, the Depression essentially shortening train conists.
I like the last version of the K4, with the solid pilot, looks more like a modern locomotive. (The crews liked the later versions also, with stokers largely replacing manual firing.)
Flintlock76 Great story in that blogspot! Very clever indeed! If only... Mind you, in the late steam era the Reading had some outstanding Pacifics, the G3 being the last, and coming out post-war, so they really wouldn't have needed a Hudson, but hey, that's a good story anyway!
Thanks. I had fun dreaming it up....
The G3s did show up on PRSL at the end. I just kinda assumed they would have stayed on home rails a bit longer since they were so "new".
54light15 Every steam locomotive that I've seen in England (and I have seen many) has a Belpaire firebox.
The GWR and the LMS liked the Belpaire fireboxes, but the LNER and to a lesser extent the Southern went the other way. The GWR and LMS regions sent quite a few steamers to Dai Woodham's scrapyard in Barry, from which many (most?) re-emerged to live again in preservation, which I presume is your experience. Virtually no LNER locos were so lucky, sold instead to more local scrappers who quickly cut them up.
CNR here in Canada had a few Belpaire boilered Mikados, but they were definitely the exception in Canada.
John
Overmod The firebox issue revolves around PRR in a sense 'gaming' the boiler safety regs on this and many other fireboxes in service. The plate thickness even without service wastage was too thin to give suitable factor of safety even at the old 4x without double-nutting some of the staybolts; the issue of more recent concern is that the new (post-part-230 and new-code) factor of safety is 5x. So the issue arises that the 'historic fabric' firebox is hopelessly incompetent even at the lowest restricted pressure that would produce meaningful performance.
I understand that post-steam era boiler safety codes have been strengthened to enhance the factor of safety of locomotives used in the excursion era and that the PRR standard Belpaire boiler used on K4 and L1 class locomotives were found to be marginal even to the rules in place when these engines were in revenue service. But I think it's a little laughable to think that the boilers used on these engines were insufficiently safe when properly maintained. That's sort of what is being implied. The PRR had 425 K4 Pacifics and 574 L1 Mikados in service using this very boiler design, many for over three decades. If ever there was a case of a well-sorted design giving safe, dependable service, this was it.
I recognize the need to have robust regulations to maintain safety, and I think the updated boiler codes requiring a higher factor of safety than used during the steam era are a good idea. But the K4/L1 boiler's service record speaks for itself. It's hard to conclude there is a safety issue with that boiler design when one takes into consideration its service record. The new boiler codes merely add margin to what has proven to be a very safe design.
When I said 'hopelessly incompetent' I was intending only the LEGAL sense, first in the Boiler Safety Law context and then the evolution of Part 230. There is certainly something to be said for PRR building 'light' to save weight or adjust distribution and they were certainly not in the business of gratuitously endangering passengers or employees with defective boilers.
It can be surprising to note the actual thickness of metal needed to contain pressure. If I recall correctly the tractor at Mentor had plate wasting to inside 1/16" before it let go. So a little fudging with double-nutting is not really putting heads in jaws. However, do not expect either a historic ICC inspector or his modern-day counterpart to allow the non-compliant version to run...
Don, I forwarded your J3a story to Jack May, who enjoyed it immensly. I am about to post something regarding the difference between the K4s, 1954, and K4s, 1941, on the Classic Trains Forum, ref. pages 58 and 60, Winter 2019 issue.
On the Duplexes and experimentals thread
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