Jones1945
I wonder how much money would have saved if PRR chose the N&W Class J instead of the duplexes. It can be calculated since the total cost of all of the duplex engines was recorded. The Js could have been the successor of both K4s and M1s, the best dual-service steam engine ever made ... Too perfect for *me!
But you are forgetting the most important lesson imparted by the high-speed testing: the class J just didn't fit enough of the PRR. Boiler was too big, for example, to run anywhere near Chicago.
Likewise you couldn't start with a Q2 boiler less one course; that was at clearance limit with only 69" ... not even 70" ... drivers.
So a putative PRR 4-8-4 would likely be more like a Niagara's running gear with a slightly downsized big Belpaire boiler that would 'just fit'. We can't use the T1 trailing truck as it's only sized for the 92' grate and structure; if you want we can modify the Q1 casting design. While it doesn't help that Baldwin, not Alco, is the 'design partner' it does have to be said that the experience with Timken rods and bearings ... and with the #4 driver pair extended crankpins cracking on the PRR-controlled N&W ... would have produced the equivalent of NYC's 6000-hp driveline right through to the hollow piston rods, probably with centrifugally-cast pistons using the 1948 T1 valve improvement techniques.
Take the cab design off the 2-10-4 for a start; if you adjust it, do so based on crew needs rather than outside aesthetics. (But keep those semilune windows!)
You have the same issues for the smokebox and front as with the Niagara, avoiding the Frankenstein "outer door" arrangement but of course preserving the 'beauty treatment' generator and headlight swap... perhaps with the two-light vertical Pyle treatment as applied to one of the T1s (to me it looks pretty good). I leave it up to you whether it gets smoke deflectors, as I personally think a Niagara looks a bit like a mobile package boiler plant without them, and this is a comparable shape.
The drivers are the fun part. Remember that 72" is M1 country and a Fleet of Modernism 4-8-4 had better have more potential; remember also that 75" on a Niagara was throwing away money and even with Central's uber-restricted loading gage they couldn't get 79" (the NYC equivalent of 80") high wheels on it fast enough. The 77" of the Q1 would (based on documents like the review of the N&W J) be about the minimum Cover et al. would have tried; the good news here is that repurposed T1 driver centers wouldn't have worked because of the designed-in short stroke, so you have a clean slate picking high-wheel cast centers or even Web-Spoke if you swallowed ... I think Baldwin had a finger in that pie ... the Fla-Vor-Aid of that approach on the non-main wheels. There is a sweet spot at 76" (see the H class and the aborted Lima 4-8-6s) and I'd be sorely tempted to exploit it with lightweight gear ... BUT it would leave you just that little notch down on the NYC for perceived high speed, with little or no true incremental gain over the Niagara in any aspect of running gear (since Alco already optimized it a bit too far)
That [a double-turbine Q] would have been a fascinating major rebuild. Though I strongly believe that it wouldn't be an economic and flexible engine which could challenge the diesel F units, it would have been a very cute white-elephant. A Q2 size welded boiler, a chassis long enough for 4-10-4 or 4-10-6, V1-style turbines, alloy steel rods, 70+ inches drivers with the best balancing, roller bearings here and there, anti-slip control, an attractive semi streamlining.
As a side note: you need neither the high drivers nor the 'best balancing' on one of these turbines, as the drive is almost entirely balanced and there is of course no overbalance surge. There are a couple of ways, including a modification of the Langer balancer, to get around the quartered augment of the side rods used; as you probably know, the S2 originally had coupling rods only on the outer pairs, but very quickly acquired a full set, so we know more about the gear arrangement than history lets on, so we design from the start for full rod beams per side plus thin Timken bearings, run as close inboard as we can make them. That's really good enough for any practical PRR working speed, which was over 90mph for the 68" drivers on the S2, especially since much of the mass advantage from the duplex principle carries over to conjugating rods in a lateral direct-drive turbine layout.
You likely wouldn't use V1 style turbines (unless the V1 design was jiggered by Westinghouse to be usable in the transverse configuration, which at the least would require some interesting exhaust-plenum design). From what we know, those were axial-flow and fairly long, with lots of room at the LP end for good exhausting. What you would want to use instead would be something like a paired-turbine arrangement (symmetrical around the main pinion in the center) -- HP admission inboard, with relatively short and inflexible HP branch manifold that easily clears the spring rigging, and large outside plena and exhaust trunking. Since you have what are in essence four blade nests, they can individually be very small; of course they are in two sizes but most of the blading itself will be common.
Reverse in this design is NOT via a separate geared turbine, it would be via an interposed idler in the main gearbox and bath. Since this would not move other than 100% from forward to reverse, it is unlikely to require either 'sprung' construction or heavy shock-tolerant mounting; it will be as high up in the gear train as possible to reduce tooth and stress forces (which is fine because we care little about how fast the idler will have to spin). Important for a dual service engine: you have the same torque, responsive to the same throttle adjustment, in reverse as you do in forward; if you want to design the engine for bidirectionality (with, for example, FM-TV from the end of the Castor/Aphrodite project for vision off the tender) you certainly could. The main implication is for the trailing truck: it will need to be stable in guiding in both directions, which a normal Delta trailing truck really isn't. I leave this as a solution for the alert reader.
I am still obsessed with the 6-wheel truck design.
Don't be. Unless you have to -- and I suspect with the more 'efficient' firebox and chamber construction you will have to.
Just as a point: the six-wheel truck costs. In the first place, for construction and fabrication with additional mass and casting complexity. In the second place, with 150% additional tread and brake-rigging wear. You lose length, have increased swing, need better steering and weight-transfer accommodation at the rear, and all for what? the ability to blow through water faster and have to make more stops. The only real advantage is the weight-bearing capability ... and weight minimization is always a good idea on modern power, especially toward the rear; you can use every pound for better auxiliaries or better circulation.
The point here is that a good modern boiler will have some version of Snyder combustion-air preheaters, which are like coils of brake-air 'radiator' pipe in weight, and a full Cunningham circulator, which involves saturated-water manifolding nearly the length of the water legs with multiple ports and vanes into the waterspace. Consider this all (on a PRR 4-8-4 design) completely aft of the rear drivers for weight-distribution purposes.
If the 4-wheel trailing truck of the Q1 could be replaced by the 6-wheel truck, it would have had more space for a larger firebox or provided more room for a completely new firebox design without sacrifice the room of the cab.
Something I guarantee you will NOT need or want is a "larger firebox", at least larger in terms of grate area. That needs to be about 100 to 104' ... but... you have the thermodynamic gains from the air preheat and then the enhanced radiant-section circulation, each accounting in tests for about a 10% increase in boiler steam-generation efficiency and neither affecting much of the potential gain from the other. Add to this the practicality of operating with sliding-pressure firing while maintaining full superheat to the turbines and you wind up with little need to go to enormous, heavy, water-filled structure or increase the actual radiant uptake surface dramatically to try to take advantage of the higher grate limit from a larger box. Fuel costs; if the additional fuel is used to boil 'more' water, the water costs; delivery of both to an engine in service is the chief rock that sank big advanced turbine steam on PRR in the first place.
But that means my fantasy white elephant would have been as gigantic as the S1 (Cool!).
Cool, yes. Necessary, no. You will note that none of the Lima six-wheel-trailer proposals had need of equally long structure at the smokebox end; in fact, the more advanced ones were only 2-8-6s (in part to gain back the length and reduced siding capacity imposed by the six-wheel rear truck). Since the firebox improvements are mostly spring-borne by the trailer arrangements and only secondarily equalized with the drivers, there are no implications other than some inertial-accommodation issues with having relatively little weight forward of the third driver pair compared to the rear, even at high speed.
Now PRR for reasons of its own will insist on a pin-guided leading truck. In my opinion what you'd get on a converted Q1 (which of course no longer has its cylinders to require low truck sideframes or outboard clearance) would be an adapted T1 outside-frame engine truck. If you wanted to have some fun here, I suspect you could easily hang one of the air compressors per side neatly in the space where the front engine cylinders had been, giving you all the accessibility needed and involving only slight adjustment to the brake piping. Then if you wanted to see if an ACFI heater arrangement works better than, say, Worthington you have room for it on the pilot beam.
However, I think they were not powerful nor fast enough in my fantasy world!
Even in a fantasy world, you have to remember the implications of basic physics and the assumption (in part driven by your stockholders) to get the greatest revenue (long-term, too) from a given capital investment. That means picking the least cost per reliable horsepower, and efficient operation over the range of loads and speeds that your railroad's profile and anticipated trainload characteristics impose.
The good news is that a PRR 4-8-4 or 4-8-6, turbine or otherwise, is unlikely to be more than a M&E 'dual service' engine; it specifically can be designed to spend a high percentage of its service life at or close to design speed with an appropriate load behind it -- the same criterion that made the Niagaras so famous and so able to run up high reliable mileage. Now, if we utilize some of Voyce Glaze's balancing conventions in a relatively high-wheel 4-8-4 we begin to have an engine PRR had little practical need for ... but was beginning to look at definite applications for. By the mid-Fifties this would have been right in the sweet spot for passenger-trucked TrucTrain consists ... run 'em as fast as the trailers will take. This in the same timeframe the Nickel Plate could make Berks pay with conventional interchange car trains. Makes you think, doesn't it?
With the help of our forumer Reed, I have the chance to read the 7-page article about the S1 in Milepost's back issue of 1992. It seems that the wheel slip problem, probably mostly occurred at high speed, wasn't solved. There were so many wheels and drivers needed to be replaced during her short service life.
Now this is important: did he say "drivers" or "driver tires"? And note that the enormous inertia of the locomotive, and the long distance from the truck pivot to the leading driver flanges, didn't make it easy for slip forces to be accommodated when (not if) they developed.
Are there answers? Yes, and many of the ones developed for the T1 are applicable on an S1. Even if we treat the 84" drivers in Golsdorf fashion and make no expectations of speed above the 110mph of the speed recorder, we need nothing more than proportional steam throttling off the Q2 analog-computer mechanism and lateral-acting rim brakes to solve the issue definitively. Just that there's no point in optimizing a 140' engine that weighs as much as a Big Boy to pull just one money-losing train.
I can see the author also noted that the S1 was *probably built exclusively for the World Fair, (the whole construction progress was unnaturally kept as a secret) but he couldn't find any solid evidence to back up this point.
The best evidence, to me, is that all the major locomotive builders conspired in the construction process. That means the engine was intended as a kind of Four Aces on steroids, a proof of the duplex 'concept' that was over the top in the same way many show cars with over-1000-horsepower quad-turbo engines are. It just happened that PRR wanted such an engine, and nobody else did. So they got the demo built to their particular wishes.
The idea of the duplex, a by-product of the competition between the New York Central and PRR ...
That is almost certainly not what it came out of. You will note that little B&O started building theirs not long after the idea was first floated, and NYC based most of theirs on PRR's second-generation design ... only to abort the whole idea before any metal was even cut or cast to make one.
Think of the duplex as the last gasp of '20s-style design, aimed at increasing practical horsepower and capacity through multiple cylinders while reducing old-school augment force on the track, and keeping all the cylinders and presumably their valve gear nicely outboard and familiar to maintenance forces. For 1933 it was a marvelous innovation; the point was that better ways to achieve high horsepower out of a 4-8-4 were only just being practically tested out -- with one glaring failure still almost a half-decade in the future.
The biggest thing PRR did with duplexes, in my opinion, was how to get four rear-facing cylinders accommodated with minimal impact on the rigid wheelbase. In a cast engine bed. The solution on the Q2, and it was a very conscious and experienced solution, was so good that its rigid wheelbase, for almost 8000hp at high speed, is actually less than an ATSF 5011-class 2-10-4 of markedly lower capacity. But, of course, unless you have an actual need (and commensurate bottom-line return on investment) for that kind of power, you're better off providing yourself with...
Pennsy low key constructed 4-8-4s based ... on their own M1s or K5...
Would have been nice to ream out important gage restrictions on suitable main lines to make larger engines possible. In particular had the stack revolution started at the end of WWII instead of waiting until the '70s, the additional clearance could have made a high-wheel class J a practical thing. Of course it would be impossibly top-heavy and head for the ditch every chance it could take, but that's another story...
It is interesting to consider what an improved Mountain could have offered PRR -- or more precisely what you'd get by putting a modern welded boiler together with Snyders and Cunningham on an M1a with a lower back-pressure front end. Remember the extra axle for carrying? Now you have a locomotive with appropriate cylinder capacity needing only the lightweight running gear to thrive ... and how many of them had PRR (over)bought by the Depression era?
And disc mains on 72" with the lightweight gear is all the improvement needed for balancing up well past 110mph...
Just no fun even thinking about streamlining one, let alone a fleet of them. Could be done, of course, but it's a waste of the weight, much like the Blue Goose shroud slated for ATSF 3765.
I really don't understand the transaction between C&O and Baldwin for the M-1 turbine electric...
It's really simple: Baldwin essentially lied through their teeth to get C&O to buy in to their project for a 6000hp single-unit turbine. Probably pointing over at the idea of N&W getting modified V1s, which is still one of those inexplicable road-not-taken stories of the mid-1940s.
Now, I'd thought (from reading the story on the Chessie in Trains) that one of the ideas behind that train was that it would be a rolling palace, something like 32 cars long assembled outside its origin station and disassembled and multiple-switched into adjacent tracks on arrival. A train that size going over C&O's grades needs a steam-turbine electric of that size to avoid double-heading or worse, even if we ignore all the slipping and other limitations of 2-cylinder simple steam locomotives doing that job.
It turns out that the plans were scaled back (and nearly everyone could get C&O ordered cars for a good price up to a couple of years later!) and of course nobody really needed a supertrain to Cincinnati (just ask B&O and N&W, who actually geared up for the potential competition in this period but to my knowledge didn't make anything much out of it) so it wound up being the capacity to take a train quicker over the mountains that could then be handled by, say, a 490-class streamlined Hudson on the flatter portions. And I really don't doubt that Baldwin told them the same lie they told N&W over the 'final solution' TE-1 design: that it was capable of high horsepower at 65mph or better.
Which of course it wasn't -- neither of them was. The turbine is relatively fixed-horsepower as designed, if it has to exhaust to atmosphere; even if it weren't, the output is pegged by generator capability. And by traction-motor limitations. Even in the absence of conductive and abrasive coal dust and liberal amounts of moisture and high sulfur in some of the coal... and so on.
A full-welded boiler, already becoming a trade possibility as the M-1s were being assembled, might have helped the design. But little in the driveline was going to 'thrive', and practical alternatives would have involved technology that really didn't mature until this century.
I'd like to have seen a destreamlined version of the M-1 run, though. That would be cool.
... for C&O's management led by Robert Ralph Young, it was probably one of the most reckless decisions ever made by the leader of a class I railroad in the western hemisphere.
I don't know if the Leader class then a-buildin' in Blighty technically counts as being in the Western Hemisphere (it would of course be very close even if not) but that makes an M-1 look like a gold-edged bond by comparison. And this was FAR from the wackiest thing the little weasel inflicted on C&O, or NYC for that matter -- by the way, you have him more or less directly to blame for why there are no preserved Hudsons or Niagaras. Just so you and Vince know.
I won't be surprised if all three of them were actually gifted to (or 70% off) C&O but I am just assuming and do not want any people getting offended.
You know, I never even thought about that angle.
My guess is Baldwin got full price both for 'development' and construction, as C&O was a cash-rich 'sucker' with only incidental exposure to more than conservative motive-power development up to that era. More interesting is that even an 'improved' J-3 type Greenbrier wouldn't have been capable of the turbine's anticipated performance; it's difficult to imagine any eight-coupled doing the work or any ten- or twelve-coupled making the time.
What I find reprehensible is how quickly Baldwin left C&O twisting in the breeze after all the showstopping problems turned up. But by then the diesel revolution and the free-piston extravaganza were in full swing there, and the finances going swiftly to hell.
When we read about the history of many class I railroads which survived the decline, they seldom or never introduce any experimental steam engine during the transitional era...
Oh, there were many; they were just stillborn and then their records were lost or disposed of. You'd have seen quite a bit more interesting steam in the late '40s and perhaps into the early '50s had GM not bought EMC and Winton in the early Thirties and then turned those talented people loose on commercializing large road power. I for one would have liked to see exactly what LV planned to do with a Q2-style duplex in a world where Alco and Baldwin weren't spurred to diesel production and Lima wasn't castrated in a merger-of-convenience.