PRR Duplexes and Experimental Engines ( S1, S2, T1, Q1, V1 etc.)

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Posted by Overmod on Friday, August 10, 2018 7:05 PM

Jones1945
As we know the higher the speed of a train consist, the lesser power the engine need to tow that consist, thus at higher speed, steam locomotive use lower cutoff.

No, that ain't so; in fact the power needed may go up dramatically at higher and higher incremental speed ranges, certainly at the point where streamlining becomes functional rather than a marketing device.  The point of shortening cutoff at higher speed is not related to 'decreasing horsepower' -- you have, I think, forgotten that cyclic rpm as a component of horsepower means that you are inducing greater horsepower at speed even though the torque per stroke is declining and perhaps becoming peakier with speed, and (as you could have mentioned) the effect of things like compression and back-pressure are increasingly 'impacting' the power from any given complete stroke.

Part of the actual effect you're discussing is that a good modern steam locomotive (and the S1 as an almost cartoon exaggeration provided some of the greatest exaggeration of all in this respect) carries a large vanity cushion of available cylinder horsepower in the overcritical water in its boiler, and can produce relatively more power per cubic inch of cylinder displacement than any engine which has to combust fuel completely inside its cylinders under the same conditions.  At the same time, a typical diesel-electric is suffering from the range of problems relating to its transmission -- most important, the effects of back EMF in DC traction motors, part of the reason any discussion of high-speed transition does not end with 'parallel' but then involves field 'shunt'.  (And the associated vastly exaggerated armature currents that become necessary, and comments about 'streetcar motors' on Raton Pass, and so forth...)  So the horsepower output of a diesel electric, where the engine is constant output at a given governor setting, can be described by a rectangular hyperbola but never exceed that bound, whereas a big steam locomotive can produce dramatically higher short-term output and, if designed for it, have the ability to use 'reserve' both to achieve faster acceleration and to run a train to higher speed.

Interestingly enough, with most of the designs I'm familiar with, including the Duke of Gloucester, the shortness of cutoff matters much less in reaching high speed.  Mallard is highly representative, with about 40% cutoff producing the record speed; I believe the calculations for the T1 so far indicate slightly greater efficiency through the poppet valves and streamlined steam tracting, but the equivalent is still around 36%.  One of the keys for high-speed running is to plan the events around the mass flow involved with that cutoff at the rotational speed corresponding to the 'top speed' you want to sustain.

Diesels, on the other hand, need more and more against the rising train resistance (you can get this to a reasonable first approximation from the Davis formula, if you don't have a dynamometer or strain gage to measure DB resistance directly).  There are figures in Brashear's book on Santa Fe power that indicate the actual drawbar pull of early ATSF diesels had fallen below 9000lb by 110mph or so (and declining more than monotonically by that point!) and this, more than just a numerical horsepower number, gives you an idea about just how such power will both accelerate and sustain a train of given characteristics.

To my knowledge, there are no objective tests sustaining a "7200dbhp" figure, and I suspect you would encounter impractical amounts of high-speed slip long before the locomotive would deliver that power through 'two sets of four' in real-world conditions.  (You can run the Davis formula for a train operated at the 'design conditions', 1000 trailing tons at 100mph with whatever adjustment for track, streamlining, etc, you care to make to get a kind of Bekenstein bound on what the required horsepower at 100mph would have to be; that's a useful exercise 'for the reader'...)

The prototype of T1 #6110 “tested on the Stationary Test Plant in Altoona, developed 6,550 hp (4,880 kW) in the cylinders at 85 mph (137 km/h)” (quote from wiki)

You're better off, probably far better off, to actually review the records of the rather extensive testing to see what horsepower was recorded under what conditions.  Joe Burgard had an extensive analysis and discussion of this on the T1 Trust internal forum and I believe he has posted some of those results in threads here (probably several years ago by now); I believe at least some of the test records are available on the Web (or from libraries and collections in Pennsylvania).  There is little doubt in my mind that 6400hp for a good T1, and perhaps for a C1a at its 'best' speed range, is achievable, provided you can accommodate the water rate, and water-treatment conditions, that correspond to that power.

Note that the Q2 was tested on the stationary plant, and given a figure in testing of just shy of 8000hp, although I don't know offhand if the S1 was tested at the time that figure was determined.  One note about the Q2 is that it was very sensitive to what I believe to be phase effect on the plant; there was so severe a difference between phase and antiphase torque that the locomotive actually surged on the rollers to the point of alarming the test crew.  (It is possible that a similar effect would have been observed on the S1 at its 'peak' output, but probably acting to limit achievable wheelrim torque as the adhesion between driver tyre and roller will be less than that between tyre and railhead.)

IIRC many powerful steam locomotives developed [their] maximum DBHP at much lower speed, take UP “Big Boy” 4-8-8-4 as an example; its firebox, boiler and total heating area were slightly bigger than S1, but It only developed 6,345 DBHP at 41.5mph.

Not a fair example, as the locomotives had large nominal GA and firebox/chamber volume to accommodate subbituminous firing -- much of which actually mimicked the characteristics of brown-coal dust firing as far as primary vs. secondary-air contribution and caloric value per ton of fuel were concerned.  Some of these characteristics should have been much better determined and calculated in the discussions of this class, as there is much more prompt heat release but limited actual heat content per ton (see the papers on the Victorian Railways experimentation with StuG pulverized firing for some relevant details plainly stated).

All these things make the figures of S1’s 7200 DBHP sound suspicious to me.

It doesn't really matter.  The take-home message, looking at the design as a whole, was that nothing like 7200dbhp could actually be reliably derived from the locomotive in service, and it would be unsurprising if, loading the locomotive as though that were an expectation, failures in service were frequently observed.

There were several spirited discussions involving the 'follow-on' design for the "T2" (code-named '5551') and one of these specifically involved using the S1's equal-length main rods in conjunction with Deem-style conjugation and cheek-plate traction control to eliminate the long frail piston rod on the forward engine.  It is interesting to consider exactly how a well-considered 4-4-4-4 can be made better than any 4-8-4 for sustained high speed; there is little doubt that for a given lightweight-rod technology the speed as well as relative durability against lateral failure is much better for the former, as is much of the cross-balance issues producing lateral 'hammer blow.'  Keep in mind that the surge component of reciprocating overbalance is solved by the Langer device (Westinghouse patent, 1947) which is driven by the same gearing that would be used to drive RC valve gear without the balance issues of external return cranks.

Overmod .....I think, inherently, the way the S1 put so much of its overall weight on the lead and trailing trucks, without any kind of adjustable equalizing or unloading mechanism to put more weight on drivers for, say, starting, had already crippled its ability to run at any practical FA.

There may be some documentation on this, but I've always just assumed that the designers figured out what tolerable axle load they could put on the four driver pairs, then just jiggered the equalizing and springing to produce that effect on the scale.  As with Glaze balancing on the J class, you want to divorce as much of the guiding force from the drivers as possible and produce relatively stiff lateral compliance (the exception being the lateral-motion device on the lead driver pair of the forward engine, which still does some of the 'steering' of the chassis, but much less than on a regular 4-8-4, that being accomplished by much stronger progressive lateral spring force on the lead-truck pivot arrangement and load imposed on the equalizing and roll-loading arrangements to give lateral restoring force.  Under such conditions on a locomotive as long and heavy as the S1 you then arrange the drivers to be 'bouncing' as little as possible at nominal FA for whatever degree of augment your overbalance provides; we know from Kiefer that if the 'critical speed' on stiff track is over 161mph, it will almost certainly be higher for higher drivers and lighter rods and valve drive, and anything short of actual bouncing off the railhead won't produce extreme hammering of the track (it's SHM up to that point) ... the question that 'should have been asked' at that point being what the antiphase lifting of the driver pairs at that point would be doing to practical adhesion at the limit...

Just curious, I understand the differences of trucks design between T1 and S1, was it possible to use softer suspension springs at both 6-wheel leading and trailing truck?

Be very sure you appreciate the design of those trucks on the T1, both in the implementation of the lead truck (which was carried over almost unchanged into the C1a design) and the placement and configuration of that somewhat-ridiculous-looking trailing truck with the axles seemingly too close together and not very well centered under the rear of the locomotive.

Those trucks on S1 had independent suspension consisting of coil and leaf springs, PRR could adjust them one by one independently according to their needs.

This is one of those timeless topics on the Yahoo group 'steam_tech' with proponents of full equalization duking it out with the (largely British) contingent who think proper permanent way makes any kind of lever equalization nugatory at best.  I am resolutely in the former category, and would expect any high-speed truck to feature equalization "inside" somewhere, even if the individual axleboxes have separate visible springs fore and aft; the situation is somewhat different from modern diesel trucks like the GE 'rollerblades' that have floating axleboxes located and laterally controlled by spring distortion, and it might be interesting to see whether the Fabreeka approach (composite shear spring) as seen in practical Centipede tenders (and in some interesting testing on N&W trucks) would represent a better approach.

On the other hand, the six-wheel trucks were unnecessary as early as 1947 in the Westinghouse follow-ups to the direct-drive mechanical turbine (the locomotive being drawn in one catalog explicitly as a 4-8-4) and they made any locomotive relatively longer than it 'had to be' (which became increasingly relevant as tenders capable of accommodating the necessary treated water for modern boiler system life even for 130-mile-long divisions ballooned in size).  It may be demonstrated that no practical circulation construction for fireboxes/chambers much larger than the T1's GA (92') could be made to run over a two-axle truck with proper steering and guiding geometry ... but the C1a certainly expected to run at over 6000hp, and the tender for it was calculated (at 64t) to produce Harmon-to-Chicago runs without refueling, something that would likely be good for at least 15min schedule reductions on Water Level Route trains (it would have been interesting, in an extremely good way, to see what C1as would have done on the CASO).  But of course this is with the obligate use of frequent track pans, and the effects on proper water-treatment dosing that go with that (particularly including oxygenation of the feedwater in the tender cistern)

Keep in mind that the C1a was explicitly meant to have almost an identical "Niagara" boiler (with the added length to line up on the slightly longer chassis) but its number sequence indicated Kiefer fully expected 6400hp from the duplex vs. 6000 from the comparable 4-8-4.  This may be analogous to the expectation of over 8000hp from the V1 turbine with a nearly-identical Q2 style boiler.

By the way, if more weight was put on the drivers, would it excess the axle load regulation?

Not unless you are Lima and fudging numbers, perhaps for management's advantage, on the only railroad built to tolerate truly extravagant axle loading at the time.  (It remains to be considered how strong the VGN trackage was for their versions).  On PRR the civil division probably always had enough 'clout' to keep the motive-power department strictly honest on its axle loads, both static and dynamic, in the years such an issue would be of concern.

And meanwhile, there was that huge investment in T1s, weighing down the books just at the time PRR needed 'better' power but impossible to peddle elsewhere...

Something to quietly remember is that even after all the design issues were solved in theory (by 1948) PRR couldn't find anyone who would buy them ... at what the equipment trust would allow them to be sold for. 

It might be interesting to see if there is any surviving correspondence about PRR offering to 'subsidize' some of the necessary purchases.  I can see some of that being tried, and the 'hatchet job' starting only when that approach had failed...

I once thought that building some HSR which linked most of the tier one cities in North East in 40s was the only way to compete with Airline or Greyhound.

It was actually much simpler than that, and I think NYC and PRR were both well aware of where to put the marginal improvements needed to make the ride better for the sleepers and the trip time a couple of hours quicker.  Remember that then, as really now, the practical 'trip time' has to be no faster than what elapses between a couple of reasonable hours after the close of business in one city to reasonably-assurable early-morning arrival before business in the other -- this being probably no better than 12 to 13 hours elapsed time, even with unfavorable time change going eastward.  There is no need for huge investments in New York and Chicago Air Line-style grade- and curve-limited construction or true HSR speeds that are fully sleeper-compatible for any of this traffic, or more southern destinations like St. Louis. 

What it does presume, of course, is (1) that the Middle Division is fully electrified, as per the 1943 engine plan, and (2) that the tunnel under Horse Shoe, and the associated line straightening, is carried through.  That turned out to be something PRR found 'more expensive' for value received than dieselizing, and while we can argue with it for romantic reasons it is depressingly hard to fully justify it at the time.

PRR or NYCRR had the best tool like T1 and Niagara but the coverage of their racetrack were not large enough.

With the problem being that much of the work 'necessary' to provide more route-miles of full high speed being just that much better when (1) electrified themselves, or (2) run with higher-speed diesels at lower effective long-term cost.  Remember that NYC was, in 1947 at least, seriously considering long-range electrification of at least part of the route, but was perfectly satisfied just a few years later, with EMD Dieseliners and implementation of CTC.  It might be quickly said that the whole case for electrification disappeared with the Great Steel Fleet.

There was little point in fixing the issue in the Pittsburgh station plant that kept the S1 from running further east.  There would be little point in running that locomotive over Horse Shoe in the first place; a complete abuse of most of the 'optimizations' of its architecture.  Interestingly, "railfans" conflated the hard restriction for the S1 with the temporary restriction (I think fixed not later than 1947) for the T1s, and to this day you will find people who confidently state the T1 couldn't operate routinely east of the entrance to Pittsburgh station without intolerable derailing/slipping/insert ignorant canard of choice.

 

But if even Milwaukee Road Hiawatha also had the same decline, I think it was not only about speed but a trend which was irreversible.

I am going to step out on a bit of a plank here, as I am almost as paranoid about F7s on Milwaukee as T1s, but in the opposite direction. 

Remember that one of the great quandaries of steam design is the utter disconnect between the lie-down-and-beg dog performance of the C&NW E-4s on actual AAR testing (couldn't get even to 100mph with the test trains) and the almost identical F7s, which supposedly reached the speeds attributed to the A-class Atlantics (120mph or better) with ease.  The Christian-Scientist-with-appendicitis issue is that when you look around you never see the F7s running faster than the low 100s in service, but you do see some fairly spectacular evidence of running-gear failure that for the longest time was covered up in the fan-press coverage of the locomotives.  And you see the F7s being taken out of service very early in the game and scrapped suspiciously fast with little attempt to preserve one, even though the replacement dieselization was haphazard at best, as bad or even worse than what happened on PRR.

Now, let me hasten to say that I sure hope I am dramatically wrong.  And that we can find someone (or the necessary group of someones) to set up a Hiawatha Trust and build replica A and F7 locomotives that can substantiate how dramatically wrong I am.  But I think this is of a piece with the ATSF 3460 class, which had little trouble reaching 100mph but needed a falling grade with a tailwind to get much above 104mph.  There are much better overall solutions for 110+mph speed, which the A class was clearly capable of and so were any of the ATSF 4-8-4s from 3765 onward.  Be interesting to see what a Niagara-size 4-8-4 built to MILW standards would have been able to do...

I don’t know why PRR given up to raise the speed of their freight services after WWII. from Q1 to Q2, they were designed for express freight service, work best at speed.

Remember that the Q1 was intended, at an earlier era of understanding, to be a practical capacity increment over the M1 just as the C&O 2-10-4s were an increment over a Berk.  As things turned out ... but, really, after 1945 ... the much better solution was lightweight rods and good valve gear and no duplexing overhead, if all you want is an M1-plus.

The Q2s were vastly more than that, and the 'smoking gun' as to what would become of them is really nowhere better seen than in the cancellation of the greenlighted-for-construction-during-WPB-times V1 prototype.  The nominal advantage was supposedly the sustained running at high speed, but a practical water rate no better than typical division length just eliminated any real advantage either of the speed or of the high horsepower.  On top of which were the much more finicky care and feeding of a high-alloy boiler pressed to higher-than-what-turned-out-to-be-practical pressure, and all the happy throng of maintenance and service problems, including the cockamamie antislip system as built.  One trembles, just as for Centipedes, to contemplate brakeshoe changes on a V1, probably a less-than-uncommon maintenance task if the engines were used anywhere near the speed or service they would be optimized for.

If PRR thought it was dangerous or impractical, why they designed and built them in the first place?

This is not fair to PRR.  When the T1 production was under consideration, the 'alternative' diesel was something like an E6, and there are perfectly good reasons why PRR didn't buy those instead of planning for T1s ... I believe the over $400K that would have been involved at the time, in gold dollars, to give equivalent horsepower at speed being one of the more compelling arguments.  Likewise, when the Q2s were developed and built, it was wartime (in the years when it was still very much thought it would take a million-man invasion with, perhaps, a million or more American casualties to take out the vicious Japanese) and, not only couldn't PRR get road diesels in needed quantities, in fact not at all, thanks to the WPB, they were still looking to a future that was not based on peacetime economization.

A somewhat better irony is that, if modern steam on PRR had remained in management favor (and not stored 'unserviceable' to where the boilers were ruined in less than a year) there might have been some openings for Q2s on TrucTrain service, where they would arguably be better-suited even than the Nickel Plate Berks were in their peculiarly steam-friendly service.  I think the outcome by then would not have been different (the issues with continuous blowdown under effective water treatment and with the snowballing nonavailability of all those proprietary little auxiliaries that were essential to the economics of big modern steam power being enough, even absent considerations of support and training, to wipe out any advantage of Q2s or even J1as for anything long-term or essential).  It might be remembered, though, that by the time TrucTrain service came to be an important potential service there were plenty of modern E units being freed up, and even then PRR didn't spend the money to put effective backward transition on them in freight service (at least as far as I know).

I heard from pervious post by our forum members that you have some evidences of PRR officials who wanted to make T1 a hopeless engine, do you mind telling us a little bit more detail about it? To be honest, I won’t be surprise if it was the truth!

I need to be careful, like any paranoid, to point out that I do not have any hard evidence that the conspiracy to kill off the equipment-trust expense was real.  There may be documents that substantiate things better somewhere at the Hagley, or in Lewistown.  All I do know is that there was a hell of a lot of storytelling going on about how bad the duplexes were, all in the direction of showing how utterly mistaken the whole idea was, much of it being from people who really, really ought to have known better or at least do better homework or fact checking.  To this day I keep having to correct people, in boring MEGO detail, almost chapter and verse about how to 'do' duplexes correctly, and what are the likely 'real' problems vs. the lies and wives' tales.  Who knows to what actual success?

Just like many flagship corporations, they are always surround by leeches; their business partners, their own employees, government officials, bankers etc., milking the host and keep it alive at the same time, so that they can milk it even more and longer.

Again, you need to remember the situation here is exactly the opposite.  PRR was on the hook to important New York bankers for a colossal sum of money, and it takes a heap of carefully-planned convincing to make those sharp-eyed characters write off an amount of that magnitude.  In particular, you will be unlikely to achieve this result if you have engineers affirming how simple some of the fixes will be (centrifugally-cast valve spools being one particularly memorable one) or you have anyone even remotely highly placed in the evolving motive-power structure who spills the beans or blows a whistle trying to polish the sow's ear as much as possible when the whole world was going to silk purses, as it were.

In perspective, it is almost impossible that either Q2s or T1s would survive in any service meaningful to them even as late as NYC was operating Niagaras.  That means no later than 1956, TrucTrains or no.  Those additional couple of years don't change much, if anything, about nostalgia or 'alternative-history' claims for longer working lives for those two classes of locomotive.

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Posted by Overmod on Friday, August 10, 2018 2:49 PM

Miningman
The fix was to set society on a new path to an entirely new society, where the marvels of massive industrial production and capitalism, through sanctioned blatant consumerism could save the day. GM was one of the major leaders in this role, but really it was everyone, from Admiral TV's to Maidenform bras to Levittowns.

I think this was perceived, and 'spun,' very differently back in the day, and with much different intent.

I doubt if many workers from the Depression era would be complaining about job availability based on an evolving 'consumer products' market.  This did, however, factor into the single biggest thing supporting Dieselization -- willingness to work hard hours in a dirty environment with only gradual advancement at tiny pay (and under lousy conditions) was not just dying out as a profession, it was disappearing completely.  This affecting not only the maintenance of the locomotives, but obtaining reliable fuel for them.

Meanwhile, the whole expansion of suburban development into relatively low-income tracts (as opposed to the Mr. Blandings Builds His Dream House in Connecticut model) and everything that implied in terms of roads, cars, and general unsuitability of light mass transit and unfinancial sense of heavy rail run only a few hours a day was perceived as opportunity and progress, and compared to a decade ago it most surely was.  The history of steam power in the late '40s needs to be overlaid with the history of All Those Streamlined Trains railroads sanguinely constructed, at huge expense, that almost never succeeded to the extent prewar experience indicated.

It could be argued that the Insolent Chariots model of "wealth creation" through accelerated depreciation and planned product obsolescence coupled with the social engineering of 'buying a new car every year' and climbing the social ladder from Chevrolet to Cadillac created far more than any mass-transit-intensive alternative possibly could have -- even with government support of what the large electric-generation companies would have had to take up.  What is not quite as clear is the tendency for cars to become sensible competition for those streamlined trains, which involves quite a bit of infrastructure as well as vehicle engineering; if you look at the experience of the New Haven with the Connecticut Turnpike as an edged example, you realize that the Interstate system was not the major impetus away from luxury trains that a simple analysis might indicate.

A bit of an illustration: in early 1969, my father dropped me off at Penn Station to ride one of the early Metroliners.  This put him on local streets with what was at the time no real direct connection to highways leading to the New Jersey Turnpike; the train departed NYP not very much later than that and ran above 100mph much of the way.  You can imagine my dismay when he met the train on the platform at Union Station, having driven out to Silver Spring and picked up some people on the way.  (And then there was the famous billboard, location carefully chosen in the depths of rust-belt industrial Philadelphia, the only brightly-lit colorful item for miles, cheerfully reminding 'You'd be there by now on the Air Shuttle'...)

The real defense, perhaps the only one outside well-defined lanes in well-defined corridors with wretched highways, was the idea of the Auto Train and services like it, like the stillborn CP idea to bridge tractors together with road trains.  I still admire a company doing this with private money, in the '70s, and there is another cautionary tale, too, in what happened to them.  But I think there was little organized effort to kill them off, just -- as in the fall of steam in the late '40s and early '50s, too many advantages synergistically applicable to competing ideas for the plan as a whole to succeed robustly or long-term.

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Posted by Jones1945 on Friday, August 10, 2018 8:34 AM

Miningman
Also I think people were traumatized by the war, wether they served or not. I believe just about the whole of society was going through a PTSD type of mental condition at some level. This was recognized by learned folks, maybe not as PTSD, but a general discomfort and disorder. People were not thinking quite straight. The fix was to set society on a new path to an entirely new society, where the marvels of massive industrial production and capitalism, through sanctioned blatant consumerism could save the day. GM was one of the major leaders in this role, but really it was everyone, from Admiral TV's to Maidenform bras to Levittowns.

Interesting perspective, Miningman. People were not only traumatized by the World War II itself, many things happened just after the war prolonged the anxiety of the whole society including officials in the government. Remember” Roswell UFO incident 1947”, “1952 Washington, D.C. UFO incident”, the establishment of NASA in 1958 etc. I don’t want to go too far since it will lead the discussion to something unrelated to the topic of the post or some forum member would call me out for trying to write a Science fiction here. I believe all these things happened after the war leaded the US government in late 40s adjusted their Policy priority on aerospace development and public transportation as well.  In short, PRR S1 #6100 looks like a rocket but it didn’t and never can take us to that creepy “natural satellite” in the space, The abandonment of Steam power development was inevitable, it is just a part of the plan of “ the highest levels, behind closed doors”......

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Posted by Jones1945 on Friday, August 10, 2018 6:25 AM

Overmod

Geometrically I think this wouldn't give the right 'thing', but having just confused a bunch of people with side-rod geometry over on RyPN I would revert to first principles.  First, the 'basis' of limited cutoff relates directly to the location of the ports in the bushings, which is determined when the cylinders and bushings are cast and machined............the TE is going to be whatever the steam getting to the cylinders at that moment, on that particular day, produces at the wheelrims for torque.  All these other figures are only approximations and possibly poor ones at that.  The number that matters is the actual drawbar pull, and you can plot that as PRR did against speed to derive a performance curve that can provide DBHP (likewise the number that matters for horsepower).



Thank you once again for the detailed reply and your patience, Overmod. I think I mixed up some technical concept in the first place, but the big picture is clearer to me now after your detail explanation! I believe the information you provided in this post will benefit everyone who found this post. ( I am still reading some post from 2006 on some forums)

Speaking of DBHP, it brings up another question about S1; the one and the only one 6-4-4-6 ever built in human history. The only source of S1’s DBHP is from Steamlocomotive.com, which is 7200hp (when hauling 1200 tons consist at 100mph), I can’t find another source of it. Maybe it is in the books which our forum members recommended in previous post but I haven’t bought or able to obtain all of them yet.

As we know the higher the speed of a train consist, the lesser power the engine need to tow that consist, thus at higher speed, steam locomotive use lower cutoff. The prototype of T1 #6110 “tested on the Stationary Test Plant in Altoona, developed 6,550 hp (4,880 kW) in the cylinders at 85 mph (137 km/h)” (quote from wiki), IIRC much powerful steam locomotive developed it maximum DBHP at much lower speed, take UP “Big Boy” 4-8-8-4 as an example; its firebox, boiler and total heating area were slightly bigger than S1, but It only developed 6,345 DBHP at 41.5mph.

Moreover, the test plant in Altoona was expanded for the new T1 prototype, which implies that S1 might never be tested on the test plant in Altoona, maybe there was another method to obtain the data of DBHP? All these things make the figures of S1’s 7200 DBHP sound suspicious to me. One year after S1 was put into service, The attack of Pearl Harbor happened, the whole nation needs some encouraging thing to improve morale, I wonder if this is one of the reasons why the 7200 DBHP figure was used?


Overmod
.....I think, inherently, the way the S1 put so much of its overall weight on the lead and trailing trucks, without any kind of adjustable equalizing or unloading mechanism to put more weight on drivers for, say, starting, had already crippled its ability to run at any practical FA.

Just curious, I understand the differences of trucks design between T1 and S1, was it possible to use softer suspension springs at both 6-wheel leading and trailing truck? Those trucks on S1 had independence suspension consist of coil and leaf springs, PRR could adjust them one by one independently according to their needs. By the way, if more weight was put on the drivers, would it excess the axle load regulation? Thank you very much!


Overmod
……Just as it would become agonizingly clear in no more than a couple more years that there was a very poor future for high-speed passenger service itself.  And meanwhile, there was that huge investment in T1s, weighing down the books just at the time PRR needed 'better' power but impossible to peddle elsewhere...
Meanwhile, the Q2s.  Very successful design ... for what they were, engines that could move critical wartime freight in 150-car trains about as fast as anyone would care to take them……  
 
I once thought that building some HSR which linked most of the tier one cities in North East in the 40s was the only way to compete with Airline or Greyhound. PRR or even NYCRR had the best tool like T1 and Nigeria but the coverage of their racetrack was not large enough. But if even Milwaukee Road Hiawatha also had the same decline, I think it was not only about speed but a trend which was irreversible.
 
 
I don’t know why PRR has given up to raise the speed of their freight services after WWII. from Q1 to Q2, they were designed to express freight service, work best at speed. if PRR thought it was dangerous or impractical, why they designed and built them in the first place? 26 Q2 plus the total number of F7 needed to replace them involved tons of money, I love PRR’s trains, but I despise their leadership and management in the late 40s.

Overmod
 
Which is why I suspect, and argue, that The Duplexes Had To Die.  And why there was, and in some respects still is, something of a conspiracy to make the locomotives and in fact the whole concept out to be a slippery total failure, a design disaster fully justifying early writeoff of a great deal of that $65 million so that the available credit could be released for things more useful in 1950s railroading.
 
I heard from the previous post by our forum members that you have some evidence of PRR officials who wanted to make T1 a hopeless engine, do you mind telling us a little bit more detail about it? To be honest, I won’t be surprised if it was the truth! Just like many flagship corporations, they are always surrounded by leeches; their business partners, their own employees, government officials, bankers etc., milking the host and keep it alive at the same time so that they can milk it even more and longer.
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Posted by Miningman on Friday, August 10, 2018 2:00 AM

How about an entirely different perspective and one that cannot be dismissed in any way. So here goes.

After WWII the government had legitimate fears of a recession, as what happened after WWI. Everyone around at the time still remembered the Great Depression like it was yesterday. It was a frightening prospect to face going right back into it. Terrifying actually when you consider all of that war industry grinding to a halt, sending millions out of work and simultaneously millions of people coming home. As mentioned this did happen after WWI and it was ugly. Riots, uprising, unrest, massive unemployment, people died. 

So at the highest levels, behind closed doors, it was decided to sell consumerism. Incredible consumerism on an unprecedented scale. After 2 decades of serious deprivation it was time to rekindle the fires with futuristic dreams. 

All the technical know how we can come up with today for the T1's or the S1, or the Niagaras's, and all the armchair retrospective what ifs and deep insights are meaningless because society was irreversibly directed into a push button future. This did not happen in Europe or Japan, they were starving and picking up the rubble. The peace had yet to be won. It was way off yet in the future. 

Steam, any steam, regardless, did not fit into any of it. The T1's horrible misfortune and rapid fall from grace was in its timing. 1945 to mid '46 was the only time period that a massive order of 50 of them would or could have been acceptable, as the full force a of new found direction and enthusiasm, now sanctioned and official policy, was just on the horizon, the next day if you will. Regardless of how functional or reliable they could be made, or how promising a future their 6 months of glory was and regardless of the dollars spent they absolutely had to go.  

Also I think people were traumatized by the war, wether they served or not. I believe just about the whole of society was going through a PTSD type of mental condition at some level. This was recognized by learned folks, maybe not as PTSD, but a general discomfort and disorder. People were not thinking quite straight. The fix was to set society on a new path to an entirely new society, where the marvels of massive industrial production and capitalism, through sanctioned blatant consumerism could save the day. GM was one of the major leaders in this role, but really it was everyone, from Admiral TV's to Maidenform bras to Levittowns.

I can understand the demise of steam, essentially a loss of a whole technology and their builders in North America, and of course we are nostalgic for what we recall.

The rapid fall of the passenger train was part of this policy, a part that I believe was not necessary at all and a serious 'one bridge too far' mistake but was caught up in the maelstrom of the times. 

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Posted by Overmod on Thursday, August 9, 2018 4:09 PM

Jones1945
English is not my first language; would you mind telling me what is the $35000 was about?

It's the equivalent of 30 pieces of silver; the amount (in 1949 money) received for the S1 as scrap.

Anyway, PRR was a quitter of their “duplex movement” when their president Martin Clement announced to remove all steam engines from through passenger trains west of the electrified territory in 1948.

Not quite - the removal only involved the first-class trains (like the Broadway) although it can be argued that restricting a 120mph engine to secondary and mail trains is something of a waste of the potential.

More to the point, it was agonizingly clear in 1948 just as it was not at all settled in 1946 that there was a very poor future for large steam locomotives in high-speed passenger service.  Just as it would become agonizingly clear in no more than a couple more years that there was a very poor future for high-speed passenger service itself.  And meanwhile, there was that huge investment in T1s, weighing down the books just at the time PRR needed 'better' power but impossible to peddle elsewhere...

Meanwhile, the Q2s.  Very successful design ... for what they were, engines that could move critical wartime freight in 150-car trains about as fast as anyone would care to take them. By the time you have to justify a four-cylinder design with dangerously-corrodible alloy-steel boiler and enormous water rate that reduces augment above 60mph on a railroad where no freight is supposed to move faster than 50mph, you should not expect to find that the design is worth All The Extra Work over, say, all those J1 versions which are perfectly happy in a 'sweet spot' around that speed.

In a long run, EMD's diesel might have saved a lot of money for PRR, but tons of money already spent on the duplex ... Not to mention The PRR bought some problematic early Diesel from Baldwin and Alco with tons of money, even more money was wasted.

Which is why I suspect, and argue, that The Duplexes Had To Die.  And why there was, and in some respects still is, something of a conspiracy to make the locomotives and in fact the whole concept out to be a slippery total failure, a design disaster fully justifying early writeoff of a great deal of that $65 million so that the available credit could be released for things more useful in 1950s railroading.

In hindsight, if PRR used their money to further improve the performance of their Duplex like applying the Franklin Type B Poppet Valves on both T1 and Q2 or other steam locomotive instead of buying this and that, we might have seen a much “romantic” ending. :P

Well, there was just exactly that approach: the development of the 'system' as well as the approach to substitute piston valves and normal valve gear on the T1s, essentially reducing the unfamiliar technology to the equivalent of a couple of fancy Atlantics (see the unbuilt E8 high-speed Atlantic design for a comparable) with much more familiar characteristics for typical PRR engineers.  In my opinion the mere fact that PRR proudly patented several aspects of the piston-valve conversion was an indication that they thought ... at that time ... it represented a good answer to making an exotic high-speed design a perfectly capable 100mph-peak/tested to 110mph locomotive.  And that the T1a was by just about any measure ... except when you have $65M down the hole and many hundreds of thousands of near-future tinkering needed just to get them reliably ordinary.  I suspect that Franklin itself would be expecting quite a bit of additional royalty money as well as cost-plus contracts to provide all the various B-2 parts to make the rotary-cam conversions, at which point I suspect that quite a few issues with rotary-cam gear longevity in general, some related to wear and stress of ball followers giving line contact (against increased spring return pressure to debounce the actual valves) bearing on expensive lateral-shifting variable cams, would have come up had for some quixotic reason PRR management decided to proceed with the full 1948 debugging and improvement program (which I firmly believe would have eliminated most of the substantive difficulties with using the T1s for reasonably high mileage in general service suited to their characteristics).

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Posted by Overmod on Thursday, August 9, 2018 3:46 PM

Jones1945
Is it possible to adjust or increase the energy output and TE of a steam engine which was using limited cutoff, by changing the angle or modify the expansion link on the Walschaerts valve gear?

Geometrically I think this wouldn't give the right 'thing', but having just confused a bunch of people with side-rod geometry over on RyPN I would revert to first principles.  First, the 'basis' of limited cutoff relates directly to the location of the ports in the bushings, which is determined when the cylinders and bushings are cast and machined.   A major point of long-lap long-travel valves is that the valve runs through a fairly extreme distance (some of the last de Caso efforts over 16"!) so that it will be moving at high speed (and hence open and close quickly to steam) at the moment the steam edge is reached with normal cutoff setting.  You will gain nothing by building the valve in such a way that it can be moved further to open it earlier or longer (which is what modifying the expansion link would have to do).  Much of the 'Holy Grail' of valve design (see for example the theory and practice of Willoteaux valves) is involved in arranging for much higher mass flow of steam ONLY in the brief range where it produces effective MEP for traction at high speed: that is not something that jiggering simple-harmonic-motion gear will produce reliably.  Likewise, a gear like Walschaerts has the same characteristics for closing exhaust that it has for opening to steam, whereas most of the important characteristics are very different ... hence the perceived importance in, say, the Franklin System or in British Caprotti for setting exhaust timing and duration very differently from admission. 

Now, D&RGW had a device for adjusting lead (on some 4-8-4s and 4-6-6-4s) that performed some of what you're wanting to do -- see here for some interesting reference material.  Note how Porta suggests this be 'optimized' with reference to pressure matching, then consider what the 'opposite side' regarding compression control would entail.

Assume I step into the cab of S1, the Reverser/Reversing lever was pushed to the forward max, does that mean its cutoff has been set to its maximum?

By definition, yes.  If you were to look outside you would see the reach rods all the way to the end of the link, moved by the linkage from the power reverse cylinders. 

... thus when the engine starts moving, it’s using maximum power and the TE would be 71900lbf instead of76,400 lbf since the machinery of the gears and everything related to TE has been adjusted to reach the 70% Limited cutoff setting?

Well no, not exactly; the TE is going to be whatever the steam getting to the cylinders at that moment, on that particular day, produces at the wheelrims for torque.  All these other figures are only approximations, and possibly poor ones at that.  The number that matters is the actual drawbar pull, and you can plot that as PRR did against speed to derive a performance curve that can provide DBHP (likewise the number that matters for horsepower).

I think, inherently, the way the S1 put so much of its overall weight on the lead and trailing trucks, without any kind of adjustable equalizing or unloading mechanism to put more weight on drivers for, say, starting, had already crippled its ability to run at any practical FA.  I think it is clear that none of the engineers who developed duplexes quite comprehended the degree to which one of the engines would lose traction if the suspension unloaded one of the wheels, with pathetically underdamped compliance, at high rotational speed and high delivered wheelrim torque, although it is pretty clear they planned for high levels with the original (ridiculously high) FA on the T1 and then the initial redesign of the equalization that took it higher still!

So you have a terribly long, terribly heavy locomotive with short stroke and reliably, efficiently high boiler pressure, that right out of the box has very low FA while retaining an underdamped suspension but does not even allow the valve gear on the two engines to be trimmed separately.  I do not need to write home to Mother to realize this dog is not going to hunt well except by combining nosing and rolling.

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Posted by timz on Thursday, August 9, 2018 12:38 PM

Jones1945
In S1 case, which figure is more appropriate to use as official figure of its TE?

What's "appropriate" mean? What's "official" mean?

PRR naturally figured they shouldn't claim 85% MEP for the S1. What's the "appropriate" MEP to assume, for an angine that cuts off when the crank has reached 114 degrees? PRR apparently just took a guess at 80%, which gives the TE they claimed. (Dunno if the S1 had auxiliary ports.)

Similarly, what's "appropriate" for an I1 with 50% cutoff? Might depend on whether engineers could count on the auxiliary ports to work.

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Posted by Jones1945 on Thursday, August 9, 2018 10:50 AM

Overmod
 These are two vastly different things.  The '85%' is a convention in the formula that corrects for pressure drop from nominal (safety-valve pop) boiler pressure to the actual pressure present at the cylinders to make power.  The limited cutoff is a characteristic of the valve gear that closes the inlet ports to steam "early" even when the valve-gear mechanism is set to full gear, thereby forcing expansive working all the time.

Yes, there were approaches to get around the issues of limited cutoff when starting, the most familiar being slot ports or 'Weiss' ports as Porta liked to call them.  Remember that even with limited cutoff and long-lead long-travel valves, the valve heads and rings still run the full stroke of the piston valve.  Providing some very thin slots communicating to throttled steam relatively early in the stroke gives some amount of admission corresponding to a steam edge earlier in the valve stroke -- but restricted by the relatively poor flow, wire-drawing effects, etc. of steam through the small aperture as rotational speed came up.

 It’s my pleasure discussing with you and learning so much from your professional sharing here, Overmod! I am not familiar with engineering knowledge, but I think I get it, though I am not sure I 100% understand the whole thing, thank you for your patience in advance if I ask some silly question! 

Is it possible to adjust or increase the energy output and TE of a steam engine which was using a limited cutoff, by changing the angle or modify the expansion link on the Walschaerts valve gear? assume I step into the cap of S1, the Reverser/Reversing lever was pushed to the forward max, does that mean its cutoff has been set to it maximum thus when the engine start moving, it’s using maximum power and the TE would be 71900lbf instead of76,400 lbf since the machinery of the gears and everything related to TE has been adjusted to reach the 70% Limited cutoff setting?
 
In S1 case, which figure is more appropriate to use as an official figure of its TE? If TE was 76400lbf, FA was 3.68 which was below average but still very close to Q2 (3.90) and higher than ATSF 2900s 4-8-4 (3.67), if TE was 71900lbf, FA would be increased to 3.91, much closer to 4 but still lower than T1 (4.33). Thank you for your patience!
 
Overmod
 
……The low FA of the Glaze-balanced J would require very careful handling at low speed, although several factors of the design would make the almost-inevitable slips easier to recover from than, say, in the S1 or T1 as built.
 
Agree! There is a video on YouTube of N&W Class J #611 hauling a heavy long consist for excursions, although the engineer handled it very carefully, minor wheel slip still occurred even though the train was moving very slowly. As we all know that Wheel slip during startup is not uncommon for a steam engine, from Class J to T1, they were controllable. But wheel slip at higher speed must be something needed to worry about. Fortunately, no serious accident happened which was caused by wheel slip during the service life of T1 and S1, Q2 didn't even have a chance to max out her speed after the war, but I am not sure how much money was spent for maintenance of rail and tire wears because of high-speed wheel slip. 

Anyway, for safety reason, I think the average operation speed of S1 was around 80 to 95mph when she needed to make up time, derailment of a 1000 tons consist like the Trail Blazer would be the biggest Public Relations disaster in PRR history. A source from German stated that it maximum speed was 120mph, I tend to believe this one, but I think it only occurred during special situation)
 
I always think that PRR should "Max out S1", even after it withdraw from service in mid-1946. Imagine PPR restored and placed her at Union Station like a piece of Art, let visitors get in the cab after paying a few bucks…… place two old dining car behind her and converted it to the fanciest restaurant in the city……. So many options, so many positive things could have been done to her instead of sending her to Scrap Cutting Torch!  


 

 

 

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Posted by Overmod on Thursday, August 9, 2018 6:46 AM

Jones1945
I have a question about PRR S1's FA (Factor of adhesion). According to Wiki: "Starting tractive effort calculated in the usual way (85% mean effective pressure) comes out 76,400 lbf (340 kN), but the engine used 70% limited cutoff (presumably to increase port openings at short cutoff) so the railroad claimed a correspondingly lower tractive effort.", Does that mean S1's TE never reached 76,400 lbf during normal operation? Was there any mechanical device to allow the crews increasing the cutoff to 85% for maximum TE?

These are two vastly different things.  The '85%' is a convention in the formula that corrects for pressure drop from nominal (safety-valve pop) boiler pressure to the actual pressure present at the cylinders to make power.  The limited cutoff is a characteristic of the valve gear that closes the inlet ports to steam "early" even when the valve-gear mechanism is set to full gear, thereby forcing expansive working all the time.

Yes, there were approaches to get around the issues of limited cutoff when starting, the most familiar being slot ports or 'Weiss' ports as Porta liked to call them.  Remember that even with limited cutoff and long-lead long-travel valves, the valve heads and rings still run the full stroke of the piston valve.  Providing some very thin slots communicating to throttled steam relatively early in the stroke gives some amount of admission corresponding to a steam edge earlier in the valve stroke -- but restricted by the relatively poor flow, wire-drawing effects, etc. of steam through the small aperture as rotational speed came up.

Compare to S1, N&W Class J had a much higher TE and lower FA but they were doing just fine, I don’t understand why PRR didn’t max out S1’s potential during the War.

Part of this involves N&W actually driving the locomotives correctly, something it would appear that too many PRR engineers had little interest in doing too much of the time.  There's always a problem with railroads wanting to get full rated power out of any locomotive as much of the time as possible, with one usual result (with steam locomotives) being to assign train consists that under many conditions will be difficult to start without care.  The low FA of the Glaze-balanced J would require very careful handling at low speed, although several factors of the design would make the almost-inevitable slips easier to recover from than, say, in the S1 or T1 as built.

The problem with the S1 towing very large consists is that this would exacerbate an already serious issue with one of the engines breaking loose and slipping either at low speed or high (two different sets of physical conditions).  This would be a formula for disaster without some 'hardware' method of trimming throttle admission to the two engines separately, with starting from many stations being a protracted agony in anything less than perfect conditions, and high-speed running being a constant and ultimately neurotic attention to incipient high-speed slips that might start over little more than a bad joint or harmonic.

Note that this is very different from getting the locomotive to pull that number of cars, or (in my opinion, reasonably) using a terminal switcher to assist in starting ridiculously long heavy consists, perhaps after having to break long consists just to get them into intermediate stations within platform length. instead of putting a booster with all its weight and efficiency issues on the S1 itself.  There is little doubt that the S1 could operate a train of tremendous length at some 'balancing speed', albeit not very happily.  But outside the performance envelope of 84" Atlantics with short stroke and high pressure under a common boiler...

Imagine if S1 could tow a named train (eg.14 cars) plus its section (eg.9-10 cars) at the same time, that would saved at least 2 K4s and 4 crews! [/quote]

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Posted by Jones1945 on Tuesday, August 7, 2018 10:29 PM
Miningman
Except the S1 was limited as to where it could run so when you get to Crestline you have this monster train, so now what do you do?... and need the crews and K4's there anyways. Pay me now or pay me later.
 
Good question. Crestline was the last eastbound station of PRR Northwestern Region before entering the Lake Region, IIRC PRR changes crews and locomotives at Crestline for both direction trains. If S1 could tow a regular named train plus its section to Crestline at once, the first thing is five hours of fuel consumed by two K4s from Chicago to Crestline would be saved, the second thing is 20 working hours (per day, approx. 400 hours per month) for four train crews saved (from two K4s). The fuel consumed by the S1 would offset the amount of money saved but I believe it still saved money for the Northwestern Region by using one S1 instead of 3 K4s.
The consist (one regular train + one section) brought by S1 at Crestline could be towed by one K4s and one T1, or three K4s sent by PRR Lake Region, depends on what this section needed. 
But people might ask if S1 could maintain an acceptable speed when hauling 25 cars or 1600 tons consist on a level track or not, I know it could, I will share with you guys later. Stick out tongue Note that T1 6,110 managed to pull 910-ton passenger trains at 100 mph, S1 had a much larger firebox, higher TE and DBHP.
 
 
Miningman
Between the Centipedes, the Bp20 passenger Sharks, the regular Sharks, the FM opposed piston offerings, the PA1's and other assorted disasters a whole ton of money went down the drain with a lot of headaches along the way. People keep stating " war weary worn out steam locomotives", but heck, Altoona rebuilt them good as new anytime, quickly, efficiently and skillfully. I think perhaps keep the steam and use it up, buy Diesel swithchers ok, let things sort themselves out and then go all in same as N&W did. Armchair stuff but that was rather easy to see.
 
Very true. Dieselization opened the chapter of PRR’s Dark Ages. In hindsight, PRR shouldn’t waste so much money on these handicapped early diesel engines. T1 and Q2, might be more expensive to maintain, but If someone able to provide a list showing how much money PRR wasted on fixing their early diesel, this and that, I bet the difference would be narrowed. While the ridership declined rapidly for years, 52 T1 and all the K4s, M1, J1 left should be enough to support the passenger service, what is the point to buy an expensive E8 and Budd Sleeper to haul a 4-car consist of Cincinnati limited or Spirit of St. Louis?
 
T1’s problem has already been fixed around 1947, they were ready to serve the people for 20-30 years, running at 100mph+, but the heads of PRR dumped them like trash! That’s why I love the 1938 version of the Trail Blazer which the whole consist of it was rebuilt from heavyweight p70 and Pullman cars but looks like a brand new car and loved by the patrons, environmentally friendly and practical!
 


(Ready to serve in the whole PRR System for 30 years or more)

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Posted by Miningman on Tuesday, August 7, 2018 1:06 PM

Except the S1 was limited as to where it could run so when you get to Crestline you have this monster train, so now what do you do?... and need the crews and K4's there anyways. Pay me now or pay me later.

As for the Centipedes, well they had 2 moments of glory...10 minutes after they rolled off the line and outside for the official photo and when they were glamourized in the painting.  

The depiction is reminiscent of a Roman Centurian or Patton slicing forward to Berlin. 

Between the Centipedes, the Bp20 passenger Sharks, the regular Sharks, the FM opposed piston offerings, the PA1's and other assorted disasters a whole ton of money went down the drain with a lot of headaches along the way. People keep stating " war weary worn out steam locomotives", but heck, Altoona rebuilt them good as new anytime, quickly, efficiently and skillfully. I think perhaps keep the steam and use it up, buy Diesel swithchers ok, let things sort themselves out and then go all in same as N&W did. Armchair stuff but that was rather easy to see.

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Posted by Jones1945 on Tuesday, August 7, 2018 11:28 AM

Hi All,

I have a question about PRR S1's FA (Factor of adhesion). According to Wiki: "Starting tractive effort calculated in the usual way (85% mean effective pressure) comes out 76,400 lbf (340 kN), but the engine used 70% limited cutoff (presumably to increase port openings at short cutoff) so the railroad claimed a correspondingly lower tractive effort.", Does that mean S1's TE never reached 76,400 lbf during normal operation? Was there any mechanical device to allow the crews to increase the cutoff to 85% for maximum TE? 

Compare to S1, N&W Class J had a much higher TE and lower FA but they were doing just fine, I don’t understand why PRR didn’t max out S1’s potential during the War. Imagine if S1 could tow a named train (eg.14 cars) plus its section (eg.9-10 cars) at the same time, that would be saved at least 2 K4s and 4 crews! 


Best regards,
Jones 

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Posted by Jones1945 on Tuesday, August 7, 2018 10:17 AM

It was a publicity pic of Martin Clemens’s ambitious dieselization plan for PRR’s Blue-ribbon fleet in 1948, the pic was heavily touched up.  Smile, Wink & Grin There is a E7 version too. 

IIRC, PRR's Baldwin "Centipede" can't even hit 100mph, top speed was 95mph. If they weren't that problematic, they actually looks loveable and interesting compare to the sea of EMD E7/8/9.......

(Baldwin Centipede, another example of "bigger =/= better " Coffee  )

 

Tags: Baldwin , Centipede
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Posted by Miningman on Monday, August 6, 2018 11:28 PM

It even illuminates the track it is on. 

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Posted by Jones1945 on Monday, August 6, 2018 11:18 PM

Overmod
....Now, if you look at PRR slang carefully enough, you'll see that 'snapper' was not just a regional term for helper service -- PRR had both 'helpers' and 'snappers' and they were not just distinguished by their location in a consist (although that is functionally important).  

Smile, Wink & Grin

The largest, heaviest and most expensive "helper" the PRR ever purchased. It was supposed to perform as good as GG1, the preferred engine of the Blue-Ribbon Fleet. Its size fitted PRR’s taste, big enough to wow its rivals, but turn out they were one of the biggest flops in America Railroad History. (source: Railroad Museum of Pennsylvania, note the passenger cars were still carrying the FOM scheme)

 

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Posted by Overmod on Monday, August 6, 2018 2:58 PM

daveklepper
Yes,routinely K4s were double-headed, especially Harrisburg-Pittsburg(h). (Often through to Crestline.) Never saw triple-heading though.

The double-heading was to create the effect of a single large road engine for very heavy Pullman consists (on the order of the 1000-ton train in the S1 spec), the rationale being the very large number of available locomotives (even more with the progression of the electrification).  In fact it would be possible to doublehead a couple of E6 locomotives and save some costs ... as mirrored in the early planning and use of the O-class electrics or a bit later in the T1 design ... but the great 'standardization' was made in the Twenties, sized to perceived requirements then, and however much a mistake it was to do that, there were far more K4s available for 'fungible' use building passenger consists essentially greater than anything possible with Algerian-Garratt style articulateds.  (And as noted, the crews would like All Those Extra Hours Every Hundred Miles On Every Train, too).  Then the size of your available train becomes constrained by things like platform length or walk to the diner, not horsepower, except in one critical respect.

That respect being getting over the fixed maximum restriction on PRR, the grade over Gallitzin including Horse Shoe.  This is where even the 'vanity cushion' of a twelve-coupled locomotive doesn't provide quite enough power to maintain road speed for the few miles of steep grade, and the third K4 would come into play.

Now, if you look at PRR slang carefully enough, you'll see that 'snapper' was not just a regional term for helper service -- PRR had both 'helpers' and 'snappers' and they were not just distinguished by their location in a consist (although that is functionally important).  You need to distinguish what the extra TE and horsepower is meant to do.  If you add locomotive power to enable a heavy train to make it 'over the hill', you have a helper.  If you add locomotive power to enable a heavy train to make time 'over the hill' comparable to, or at least faster than, the train can make on either side, you have a snapper.  And the selected class of snapper locomotive can't be, say, like the 2-10-2s used to drag diesel streamliners up the likes of Cajon; they have to be smooth-riding at the speeds expected.

So if snapping were desired, as on one of the 'first-class' trains, you might expect triple-heading, but only over certain divisions.  Otherwise expect the fact of the double-heading to be able to maintain reasonable (albeit lower) speed, or the ability to traverse Horse Shoe without external helper, for less extreme or less demanding trains.

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Posted by Jones1945 on Monday, August 6, 2018 10:30 AM

daveklepper

They should have been envious of the Central's "Water-Level" route,  It was that, more than superior motive power, that avoided double-heading on the Central.

Yes,routinely K4s were double-headed, especially Harrsburg-Pittslbugh.  (Often through to Crestline.)  Never saw triple-heading though.  Have any evidence?

I read some articles mentioned about Triple-heading K4s, probably happened during World War II at the Horseshoe curves, but I never have seen any photographic or video evidence so far. Triple-heading after the war must be as rare as a double-headed T1 (jk).

Btw, many think that PRR T1 was not welcomed by the crews because it replaced double-headed K4s; an operating arrangement which ensured their living hood. 

 

Smile, Wink & GrinIn case you missed some "K4s action":



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Posted by daveklepper on Monday, August 6, 2018 9:44 AM

They should have been envious of the Central's "Water-Level" route,  It was that, more than superior motive power, that avoided double-heading on the Central.

Yes,routinely K4s were double-headed, especially Harrsburg-Pittslbugh.  (Often through to Crestline.)  Never saw triple-heading though.  Have any evidence?

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Posted by Jones1945 on Sunday, August 5, 2018 10:22 AM
3rd rail
The Pennsy guys were a bit envious of the NYC Hudsons just to their north... It took two, sometimes three, K-4's to get a passenger train across the Alleghenies, while the "Central" whisked along with a single J-3.. At 90 mph.. 
 Now, John talked about running a T-1 from Crestline OH, To FT. Wayne IN hitting over 100 mph, but I can only imagine...   Look at that line today.  Weeds  and rotten ties. Ah, what a shame....... 
Todd
 
Interesting point of view from the crew of PRR, Todd. I agree with you that K4s was probably the best steam engine PRR ever had, although many crew love M1 even more.  

The Tractive Effort of PRR K4s, (a Pacific 4-6-2) were even higher than NYC J-3 (a Hudson 4-6-4) without a booster, I have seen quite a lot of videos, some available on YouTube, showing a single head Streamlined K4s running at 80+ mph with 8-10 cars behind. K4s didn’t even need a booster to start a heavy train, S1 and T1 also didn’t need it, since they can make up time at 100mph+ whenever and whatever they want. Time

Wheel slip problem of S1 and T1s has been discussed for 70 years after more and more documents like operating records and testing report revealed in recent years, it's almost a consensus that their wheel slip problem was exaggerated and wasn’t uncontrollable.
 
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Posted by 3rd rail on Sunday, August 5, 2018 7:50 AM

WELL, While they were pretty to look at, I heard it from the "Horses Mouth" (John Crosby) who was an engineer on the Ft.Wayne line at the time, The S-1 was a total disaster. Slippery, and a real B!tch on curves. The T-1's were not any better.The T-1 would slip like hell starting a train. It was standard operating procedure to assign a pusher to get a T-1 led train out of Columbus Station.   Best thing before the E-7's were the K-4's. Sure, dirty to work on, but sure-footed and could make the time. The Pennsy guys were a bit envious of the NYC Hudsons just to their north... It took two, sometimes three, K-4's to get a passenger train across the Alleghenies, while the "Central" whisked along with a single J-3.. At 90 mph.. 

 Now, John talked about running a T-1 from Crestline OH, To FT. Wayne IN hitting over 100 mph, but I can only imagine...   Look at that line today.  Weeds  and rotten ties. Ah, what a shame....... 

Todd 

 

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Posted by 3rd rail on Sunday, August 5, 2018 7:47 AM

WELL, While they were pretty to look at, I heard it fron the "Horses Mouth" (John Crosby) who was an engineer on the Ft.Wayne line at the time, The S-1 was a total disaster. Slippery, and a real female dog on curves. The T-1's were not any better.The T-1 would slip like hell starting a train.   Best thing before the E-7's were the K-4's. Sure, dirty to work on, but sure-footed and could make the time. The Pennsy guys were a bit envious of the NYC Hudsons just to their north... It took two, sometimes three, K-4's to get a passenger train across the Alleghenies, while the "Central" whisked along with a single J-3.. At 90 mph.. 

 

Todd 

 

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Posted by Jones1945 on Sunday, August 5, 2018 2:20 AM
My order of Loco Profile, 24 is arriving, I wish I can find some new detail in this 24-page booklet... In the past few years I put my focus on S1, T1 and Q2, seldom give too much attention to S1, anyway I think it is not possible to find another video footage of S1 in service (probably get thrown away like trash so many years ago) I can't even find the info of total mileage or average mileage per month of S1. But I found some interesting stuff of the Trail Blazer, I will share it on a new post, please stay tuned! Smile

_________________________________________________________________

IIRC both unique 3-axle trailing and the leading truck had independent suspension, consists of coil and leaf springs. The same type of trucks was used on S2 which make both engines had an impressive and unique look, they ensured good ride quality too.

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Posted by Jones1945 on Friday, August 3, 2018 2:26 PM
S1 1941
(Ron Ziel Collection, click to enlarge)

Imagine the air current created at that front shrouding which covered the coupler, when the engine speeding at over 100 mph. The front coupler cover was lifted up during her entire (except the first few months) service life from full-skirted period to de-skirted period, probably not only for better accessibility but also to dredge air stream. Another possibility was to provide better cooling for both Worthington 7-SA water pump under the streamline shrouding.
 
Photographic evidence showing that the front coupler cover on K4s #3768 seldom lifted up, probably because it was officially tested in a wind tunnel many times and it was partially de-skirted not long after she was put in service. However, I never heard or seen any info or pic about S1 or even T1 subjected to wind tunnel test. T1's front end has an improved design which was a Radiator Grille look-alike feature and three (supposed to be four) portholes to dredge air stream and ensure better cooling for the Worthington water pump. I especially like the prototype’s front end, but the heads of PRR did not.
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Posted by Jones1945 on Wednesday, August 1, 2018 4:00 AM

M636C

......Allen's own description is similar but less colourful. He did mention that two cast iron rail chairs in the curves had fractured...

LMS Vice President Sir Ernest Lemon said, at the press lunch:

"Of course, gentlemen, you will realise that we shan't need to do this kind of thing on every trip of the "Coronation Scot"; we were coming in a little faster than we shall have to do in the ordinary course..."


It always amazes me that the weight of PRR S1 without the tender was 304 short tons, PRR T1 was 251 short tons while LMS The Coronation Class was only 121 short tons!


A 9 cars consist of LMS, The Coronation Scot was 317 tons (including Kitchen cars) with a maximum capacity of 166 passengers.

Nine P70KR coaches in the consists of PRR, the Trail Blazer was 657.45 short tons with maximum capacity of 504 passengers, assuming the twin diner car and the head end, P70GSR coach and POC70R coach-observation had the same weight as the P70KR, the total weight and maximum capacity of the Trail Blazer (Pre-war version) consists was 1022 short tons and at least 588 passengers!

Average tonnage/passenger ratio of the above-named trains was 1.91(LMS) and 1.74(PRR) respectively. I used to have a false impression that passenger coaches in the State were built unnecessary heavy compared to UK's, but now I changed my mind.

Anyway, not all of the named train of PRR were all coaches train like the Trail Blazer, full Pullman sleeper train like the General and the Broadway Limited had much lower capacity, not to mention the pathetic ridership of the latter during the pre-war period......

LMS and PRR streanliner
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Posted by Jones1945 on Wednesday, August 1, 2018 2:30 AM

M636C

To revert to the original request, here are a couple of references:

Loco Profile 24 "Pennsylvania Duplexii" by Brian Reed Profile Publications Windsor UK, 1972.  Brian Reed was a locomotive design engineer with the North British Llocomotive Company.

"Rekord Lokomotiven" by Wilhelm Reuter, Motorbuch Verlag Stuttgart 1978 pp 303 to 315, chapter title "The Big Engine".

Peter

Thank you very much, Peter. Those are some publishment form 70s, I wonder if it is still possible for me to find them. I really want to read them, If our forum members own these publishment and willing to share with me, please kindly pm me! Thank you very much!! 

(Edit: I found a copy on the web of Loco Profile 24, but I am not sure if full name of  "Rekord Lokomotiven" by Wilhelm Reuter = "Rekord Lokomotiven - Die schnellesten der Schiene 1848-1950", I can found plenty of them on amazon but I can't read German...... Beer

Book

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Posted by Jones1945 on Wednesday, August 1, 2018 2:09 AM

 

Overmod
Meanwhile, the original Baldwin design provided for the T1 'thought' that all the drivers in both engines should be equalized together, which required some cleverness to get past the cylinder block for the rear engine.  Their solution was the long pivoted beam on the prototypes.
Thank you very much, Overmod. I remember S1 also had the same long pivoted beam between two set of drivers, and she was designed by Baldwin, Alco and Lima Locomotive Works under a joint contract, so I assume that using a long pivoted beam (which actually looks like a pair of huge reversed leaf springs) was a consensus between them, even though it turned out to be a unnecessary structure of the duplex design. Unfortunately we have no detailed documents or records about the progress of the making of S1 and all detailed record of the ideas shared between BLW, Alco, Lima as well as PRR, if not, it would be an interesting read!

(A "concept car" under construction in 1938 Stick out tongue Note the long pivoted beam under the rear cylinder)
S1 underconstruction

Overmod
One big advantage that came into postwar truck design was the use of  'silentbloc' rubber bushings at contact points and joints.  The French in particular made heavy use of this (and I think it was instrumental in achieving some of the contemporary high speeds reported for the equipment as early as the Fifties).  
 
Interesting! Speaking of the use of rubber on suspension, I remember it was adopted not only to train but also tram(streetcar) truck in the UK around late 40 to 50s, some of the tram truck design use rubber to replace the original leaf spring on the primary suspension, it reduced noise and ensured a smoother ride at low speed. If you want to know how the ride quality is, you could go to Hong Kong, their tram still using the original tram truck from the mid-40s.
(pre-war tram truck with its primary supension modified from using leaf spring to rubber)

Pre war tram truck
 
Overmod
What's the source for the streamlined-duplex 'cut' you provided?  That looks like something a British enthusiast would provide for a C1a using an auxiliary and perhaps corridor tender instead of track pans; we made very little use of that kind of deep angle cab even with vestibule, and the NYC cabs that had vestibules (the Niagara and A2a Berk important examples) had them up near deck height.  Is there a story associated with the picture, or more explanation of its origins?
 
It is a collection I found at the online archive of the Museum of Pennsylvania (they allow direct sharing of their online collections), the description is very simple. “1946, Proposed Streamliner for New York Central, Baldwin negatives” They do have two more drawing of it (show in pic below) with the name and signature of the designer or artist. I guess it was Baldwin's proposal of their direct-drive steam turbine engine (PRR S2 6200) for New York Central in 1946 to replace their Dreyfuss Super Hudson, the design of it reminds me of Otto Kuhler ‘s style. Unfortunately, the direct-drive steam turbine designs probably needed much more time to make it work to fulfill the State’s operating environment and requirement. On the other hand, streamlining steam locomotive is no longer a fancy thing after the war, NYC didn’t streamline their Niagara which would be adding unnecessary weight and wasting manpower for their fleet. Even PRR removed the streamlined shaurding of their 5 K4s like what NYC did to their Dreyfuss Hudsons and modified the front end of T1, completely changed its stylish looks.

 

Baldwin turbine proposal

 

 
 

BLW turbine proposal

 

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Posted by M636C on Wednesday, August 1, 2018 1:05 AM

I have more information regarding the 1937 test run of the Coronation Scot and its description mentioned by Overmod.

There are three separate descriptions of the entry to Crewe in Cecil J Allen's "British Pacific Locomotives" from Ian Allen in 1962. My first edition has the price "65 shillings" pencilled in the back. The 1937 run is covered on pages 137 to 139.

R.A.Riddles, later credited with the design of the BR Standard locomotives, was riding the locomotive.

Part of his description reads:

"Spectators from Crewe coming into view along the lineside; and the train still hurtling at 114 miles an hour. On went the brakes, off the regulator but on we sailed, flames streaming from the tortured brake blocks....   We were still doing 60 to 70 miles an hour when we spotted the platform signal. The crockery in the dining car crashed. Down we came to 52 mph through the curve, with the engine riding like the great lady she is. There wasn't a thing we could do but hold on and let her take it. And take it she did; past a sea of pallid faces on the platform we ground to a dead stand, safe and sound and still on the rails."

Allen's own description is similar but less colourful. He did mention that two cast iron rail chairs in the curves had fractured...

LMS Vice President Sir Ernest Lemon said, at the press lunch:

"Of course, gentlemen, you will realise that we shan't need to do this kind of thing on every trip of the "Coronation Scot"; we were coming in a little faster than we shall have to do in the ordinary course..."

Peter

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Posted by M636C on Tuesday, July 31, 2018 8:58 AM

Miningman

Well thank you for that erikem. Wow that's some kind of twisted up thinking on the government's part.

 
 
An example of twisted government thinking...
 
In 1986, the Australian Government introduced a "Fringe Benefits Tax". So if a company provided a car to an executive, his tax was increased by the nominal extra income that would have been paiid for him to buy and run the car.
 
Mc Donnell Douglas employed senior engineers in Australia at that time to assist in the local assembly of F/A 18  fighter aircraft for the Royal Australian Air Force. These people were paid their USA salaries, but Australian taxes were higher than those in the USA. So McDonnell Douglas paid the difference between the USA and Australian taxes. This paying of tax of course was a fringe benefit, so the Australian Government increased the tax paid by the engineers to compensate. This was paid by McDonnell Douglas. But it was an allowable cost of operation, so Mc Donnell Douglas were able to charge the total extra tax, plus 20%, to the Royal Australian Air Force, who ended up paying 141% of the tax differential for the engineers concerned.
 
I understand that Canada is buying the best of the remaining Australian F/A-18s to replace older Canadian aircraft of the same type. So if you see one, remember them as an example of government taxation gone crazy...
 
Peter
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Posted by M636C on Tuesday, July 31, 2018 8:12 AM

To revert to the original request, here are a couple of references:

Loco Profile 24 "Pennsylvania Duplexii" by Brian Reed Profile Publications Windsor UK, 1972.  Brian Reed was a locomotive design engineer with the North British Llocomotive Company.

"Rekord Lokomotiven" by Wilhelm Reuter, Motorbuch Verlag Stuttgart 1978 pp 303 to 315, chapter title "The Big Engine".

Peter

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