The original Loewy Triplex that I recall had the drivers under the 'central' boiler, with trucks at either end. There was no loss of TE as fuel and water levels changed. I remember the presentation being nonarticulated (and only six-coupled!) but that might have been just for 'show' as in so many of these locomotive-scheme patent drawings.
You will note that the V1 comparison curve is plotted only to a comparison speed well below "100mph" (although a properly-designed mechanical turbine can, of course, reach much higher speeds) -- in fact, I thought it interesting that the S2 comparison line goes all the way up to 85mph, higher than other locomotives traced, and is trending 'better' than the V1 (with original drive) at that point. (The original of this graph is in the Hagley files, and is a beautiful thing in multiple colors).
Your best bet with the Bowes drive, since I don't have the patent list handy, is to start with the Bowes collection finding aid at the Philadelphia seaport museum. Note down the various patent numbers and then use Google Patents to download the PDFs (don't go by the online text; it is often poorly rendered and viewing the drawings is essential to understanding both the principles and the detail design of the various kinds of drive).
From the handwritten presentation in the Hagley files, I had originally thought of the drive as a kind of electromagnetic slip coupling, a bit like a magnetorheological clutch but without fluid between its armature and field. But it is more complex than that, as you will see; think of a motor with two opposing armatures, one rotated by an external shaft, the other driving the output, both with magnetic-phase control. A modern version using multiple salience and intelligent phase control becomes both more cost-effective and far more robust.
Note that the V1 was not supposed to be 6900hp but 8000hp (this being directly related to the steam-generation potential of the welded version of the Q2 boiler), little if any turbine power being 'wasted' in the direct drive. The original version was probably direct-connected much like the S2 at 'right angles', but it would likely have been practical to install at least a Maybach clutch to allow the turbine to be warmed and 'dewatered' before attempting a hard start into load. With a Bowes drive, of course, this is much simplified.
The postwar version of the V1 began to be touted as "9000hp" in PRR literature, but this is likely at least partly PR 'vaporware' as the changes to a Q2 boiler to achieve the necessary mass flow would be difficult and, of course, the water rate colossally useless, almost defeating the purpose of most high-speed working. That's not to say such horsepower wasn't needed or couldn't be used, only that PRR was beginning to have experience with high pressure and alloy steel in their normal service, and it wasn't proving very pretty especially with typical track-pan water quality...
Overmod ......I thought Loewy's "Triplex" idea went considerably further back than 1941 (I don't have my notes available, but I seem to recall 1934) and was somewhat different in detail: it involved separating the locomotive into three 'modules' containing water, fuel, and boiler (hence the 'triplex' designation). Why PRR persisted in calling the design that became the V1 the 'triplex' as long as they did is something of a mystery to me, as it's clear in some of the correspondence preserved at the Hagley that it's not what Loewy had developed or intended. (As an amusing counterpoint, I have seen a Lehigh Valley diagram for a proposed duplex that features an enigmatic vehicle that is probably an integral separate water tender 'module.')......
......I thought Loewy's "Triplex" idea went considerably further back than 1941 (I don't have my notes available, but I seem to recall 1934) and was somewhat different in detail: it involved separating the locomotive into three 'modules' containing water, fuel, and boiler (hence the 'triplex' designation). Why PRR persisted in calling the design that became the V1 the 'triplex' as long as they did is something of a mystery to me, as it's clear in some of the correspondence preserved at the Hagley that it's not what Loewy had developed or intended. (As an amusing counterpoint, I have seen a Lehigh Valley diagram for a proposed duplex that features an enigmatic vehicle that is probably an integral separate water tender 'module.')......
Thank you very much, Overmod. It seems that you and me are the only two forum member who knows or interested or willing to talk about this topic at the moment! I remember I found other simple drawing of Loewy’s “Triplex” before 1944 but I can’t find them anymore, it was in the Google Patents IIRC.
By the way, I wish I can find a detailed drawing of Bowes drive so that I can’t at least understand how a direct-drive turbine can work on PRR’s V1 (two modules) design.
I do admire the craftmanship of S2’s firebox. Working under such dangerous operating environment, it still managed to not explode but cracked on here and there…… By the way, now I understand that S2 was supposed to be a passenger engine while V1 was for freight services. Since 6900hp was not enough to handle heavy freight train, but ironically V1’s design top speed was 100mph.
The original Loewy ”Triplex” was a three “modules” design, it would looks like a Garratts (eg. 4-8-2+2-8-4) without articulation. Without articulation, TE of both Fuel and water modules would decrease during operation if there are drivers under these modules.
Jones 3D Modeling Club https://www.youtube.com/Jones3DModelingClub
I thought Loewy's "Triplex" idea went considerably further back than 1941 (I don't have my notes available, but I seem to recall 1934) and was somewhat different in detail: it involved separating the locomotive into three 'modules' containing water, fuel, and boiler (hence the 'triplex' designation). Why PRR persisted in calling the design that became the V1 the 'triplex' as long as they did is something of a mystery to me, as it's clear in some of the correspondence preserved at the Hagley that it's not what Loewy had developed or intended. (As an amusing counterpoint, I have seen a Lehigh Valley diagram for a proposed duplex that features an enigmatic vehicle that is probably an integral separate water tender 'module.')
Cover et al. made much of the fact that Baldwin's design for the C&O M-1 was done in great secrecy and relatively great haste but largely to get around any prospective Steins patents rather than try to steal priority -- you may notice that many of the basic design features are very different. If I recall correctly Baldwin was also thinking they would have a leg up on having a steam turbine product to promote and sell 'ahead' of anything PRR or BCR could develop ... this being the practical follow-on to large passenger locomotives required to pull long trains of axle-generator-served modern air-conditioned cars. (There are highly revealing graphs of trailing resistance in Kiefer's report showing the effect on acceleration rate as the axle generators are cut in progressively). Note that Chris Baer's sources specifically include the files at the Hagley that I reviewed concerning the V1.
Note the considerable differences between the GE 'turboelectric' (which was a follow-on to the first-generation experiment sold to the UP in the late Thirties) and anything PRR is doing with turbines at this point, either with the S2 or the V1 which are direct-drive through gears. It is important to keep the various lines of development separate, especially as when you extend this development to its logical conclusion at N&W you will see one of the earlier "improvements" being a switch to electric drive, in part to utilize the 'wasted' carrying axles for additional traction.
There is also poor distinction in the records regarding use of steam turbine locomotives for high speed passenger work (the V1 as greenlighted in 1944 being intended as a freight locomotive). Loewy's design patents clearly show a passenger shell suited for this chassis, and the use of the Bowes drive should have permitted better starting and much faster running than the original version.
A word on the S2 front end: It was fairly common knowledge that a steam turbine in locomotive service requires a very large exhaust plenum volume (and effective cross-section) in order to simulate the conditions of marine condensing (where the effective pressure at the turbine outlet can be considerably below atmospheric or gauge pressure due to the phase change). This is clearly seen in the plenum for the '30s GE high-pressure turbine, and in the front end for the S2 which used four separate nozzles and stacks in an arrangement similar to that proposed for the UP FEF-4s. A problem with the S2 was that, at starting, there was considerable 'slip' of steam both around the tips and through the blading with the turbine at low speed (this was not reflected in a loss of starting TE, as some PRR correspondence as late as 1946 was at pains to demonstrate) and this quite cheerily induced glorious vacuum relatively quickly after full-power starting had begun. This was a disaster waiting to happen as soon as one engineer had forgotten about this difference and horsed the throttle open (or slipped the engine at starting) as the draft induced high combustion and gas temperatures and steam consumption soared inducing what were probably DNB conditions in parts of the water legs. Result was popped staybolts, and lots of them, with consequences not many would enjoy contemplating. In my opinion some of this trouble could be solved by using only part of the available nozzle capacity at low speeds (or regulating the rate at which draft could be physically induced during acceleration) and there are front-end arrangements, including those using aerodynamics to augment gas eduction, that supplement large plenums in achieving low exhaust back pressure even at high steam mass flow at the high speed a turbine passenger locomotive would expect to work much of its time.
The evolution of Raymond Loewy's "Triplex" :
In this thread, I am going to create a compilation of information about the Raymond Loewy "Triplex" and PRR V1 direct-drive turbine locomotive. I will gather all information from The PRR Chronology in the first phase, please feel free to sharing all your thought with us!
This thread will keep updating when new information is avaliable.
Apr. 10, 1943 | Raymond Loewy’s office applies for three design patents covering the streamlined shell of the proposed “Triplex” steam turbine locomotive. (VPO)
Jan. 4, 1944 | Mechanical Engineer Carleton K. Steins receives patents Nos. 2,338,212 and 2,338,214 covering a turbine or reciprocating locomotive with a tender first, followed by the cab, and then the boiler with the firebox forward, the proposed V1. (VPO)
Feb. 8, 1944 | Chief of Motive Power H. W. Jones writes to Carleton K. Steins asking him to discuss the steam turbine V1 “Triplex” locomotive with the Baldwin Locomotive Works. (VPO)
Feb. 9, 1944 | With the patents granted, Carleton K. Steins writes to Chief Engineer Ralph P. Johnson of the Baldwin Locomotive Works arranging to discuss the “Triplex” steam turbine locomotive when they next come up to discuss the Class Q2. (VPO)
Apr. 12, 1944 | Pres. Clement meets with heads of other coal-hauling railroads to promote the development of a coal-burning turbine locomotive.
Apr. 12, 1944 | Mechanical Engineer's office issues specification drawing for proposed Class V1 4-8-4-8 steam turbine "Triplex"; twin turbines developing 9,000 HP with top speed of 100 MPH; 48" drivers; total weight 882,000 lbs.; starting drawbar pull 115,000 lbs.. (CMP)
June 22, 1944 | VP in Charge of Operations John F. Deasy requests Pres. Clement to approve development of an experimental Class V1 2-D+2-D streamlined steam turbine locomotive, for which $400,000 is to be charged to capital account and $350,000 to operating expenses; it is to use the same boiler as the Q2 but which can develop 115,000 lbs. of starting tractive effort from two 4,500 shaft HP turbines; the coal bunker is to be equipped with auxiliary water tanks, so that water can be pumped forward as the coal is depleted to maintain weight on the front driving unit; overall length is to be 137'-5" and total weight 882,000 lbs.;
the V1 is to have clearances similar to the J1; it will require 125-foot turntables, of which there is presently only one at Harrisburg, so that a new turntable will be required at East Altoona; track troughs at Jacks and Latrobe would have to be lengthened from 1,800 to 2,600 feet; Deasy proposes using it on the Middle Division and in helper service between Altoona and Gallitzin, althought he forsees its use between Enola and East St. Louis/Chicago using the Port Perry Branch to get through Pittsburgh; development work begins without formal authorization from Board. (VPO)
Sep. 13, 1944 | PRR Board authorizes the expenditure of $375,000 for a 4,000 HP EMD E7 A-A set; track changes at “Q” Tower at Sunnyside Yard; approves a contract between the railroads and the General Electric Company for a coal-burning steam turbine electric locomotive of 5,435 HP. (MB)
Oct. 18, 1944 | Motive Power Dept. prepares a performance curve showing the proposed Class V1 turbine locomotive outperforming all PRR conventional steam locomotives and even the Chesapeake & Ohio Railway’s 2-6-6-6 “Alleghany” Type at all speeds over 25 MPH. (VPO)
(S2 #6200)Nov. 28, 1944 Experimental Class S2 6-8-6 steam turbine locomotive No. 6200 placed on display for press at Philadelphia; developed by Baldwin with turbine components by Westinghouse; proposed T1-type Loewy streamlining has been rejected; develops 6,900 HP at turbine shaft. (Hirsmaki says in service 10/1/44!! 11/28 is date of press event!! NYT); simplified smokebox design leads to staybolts breaking and steam leaks, although turbine performs well. (RyAge, CMP)
Nov. 28, 1944 | Pres. Martin W. Clement asks when the company will be able to make up its mind on the Class V1 turbine locomotive and whether it will be used for freight or passenger service. (VPO)
Jan. 29, 1945 | VP in Charge of Operations John F. Deasy proposes that the Baldwin Locomotive Works and Westinghouse Electric & Manufacturing Company collaborate with the PRR on developing a prototype of the Class V1 turbine locomotive; Chief Electrical Engineer John V. B. Duer writes to the Baldwin Locomotive Works concerning the patents, particularly possible patent infringement from the similar steam turbine locomotives that Baldwin is building for the Chesapeake & Ohio Railway. (VPO)
Feb. 21, 1945 | H. W. Jones, John V. B. Duer, Carleton K. Steins and J. S. Stair of the PRR meet in Philadelphia with representatives of Baldwin Locomotive Works and Westinghouse Electric & Manufacturing Company in Philadelphia and agree that they will develop and build a prototype Class V1 coal-burning direct-drive turbine locomotive on the same terms as they have built the Class S2 No. 6200; Westinghouse will design the turbines, gearing and drives, Baldwin the locomotive, and the PRR only the driving and guiding trucks; this has the effect of raising the costs of the locomotive from $750,000 if built at Altoona, to $975,000. (VPO)
Feb. 25, 1945 | G. M. Humphrey, Pres. of the M.A. Hanna Company writes to Pres. M. W. Clement complaining about the announcement of the Class V1; the PRR has chosen a side view to emphasize the difference in arrangement from a conventional locomotive; Humphrey would have preferred an angle shot that emphasized the streamlining and “modernity” still possible in a coal-burning locomotive. (VPO)
Mar. 20, 1945 | PRR announces completion of design of Class V1 "Triplex" 9,000 HP 2-D+2- D steam turbine locomotive to be built jointly with Baldwin and Westinghouse; to be 137.5 long; falling revenues after end of war preclude construction; also announces pending construction of Class Q2 duplexes. (PR)
Mar. 20, 1945 | Raymond Loewy responds to the V1 “Triplex” locomotive publicity complaining that he originated the “Triplex” concept in 1941 and “suggesting” that future publicity state that it “was conceived by the Pennsylvania Railroad’s Consulting Designer, Raymond Loewy and developed by the railroad’s engineering staff ...”; he also complains about the poor quality of the rendering supplied to the press. (VPO)
Mar. 26, 1945 | VP in Charge of Operations John F. Deasy responds to Raymond Loewy’s criticisms by noting the Loewy’s original “Triplex” design was for a three-unit reciprocating locomotive, whereas the PRR’s engineers have replaced it with a two-unit turbine design; he promises that Loewy will be given credit for styling the V1 when it reaches that point. (VPO)
Mar. 28, 1945 | Chesapeake & Ohio Railway asks War Production Board to build three steamturbine-electric locomotives similar to the projected PRR V1. (RyAge)
Apr. 28, 1945 | PRR Pres. Martin W. Clement questions VP in Charge of Operations John F. Deasy where the Class V1 turbine locomotive can be used if successful.(VPO)
June 22, 1945 VP in Charge of Operations John F. Deasy replies that the Class V1 turbine locomotive should be used between Harrisburg and Altoona, as it will have enough coal to operate 160-170 miles at 50 MPH. (VPO)
Sep. 25, 1945 | VP in Charge of Operations John F. Deasy submits a new AFE for $975,000 for the construction of one Class V1 steam turbine locomotive; the Accounting Dept. questions whether the increase in cost of $225,000 is because the locomotive will be built by outside builders, Baldwin and Westinghouse, instead of at Altoona; if so, the additional charge cannot be made to operating expenses; this means that $500,000 must be charged to Road & Equipment. (VPO)
June 13, 1946 | Chief of Motive Power Howell T. Cover request the use in the proposed Class V1 turbine locomotive of an electric drive and reversing mechanism invented by Dr. Thomas D. Bowes, naval architect and used in ship propulsion; it will raise the cost of the complete locomotive by $10,000 to $985,000; Cover recommends building and testing one truck complete before proceeding with the whole locomotive, and speed is necessary to secure the use of the patent if it proves successful. (VPO)
June 19, 1946 | VP in Charge of Operation John F. Deasy formally submits to Pres. M. W. Clement a proposal to first build a truck with the Bowes drive and complete the design of the Class V1 turbine locomotive for $578,000, followed by construction of a complete locomotive for a total of $985,000; he urges speed to prevent the Chesapeake & Ohio Railway from claiming patent priority. (VPO)
Aug. 20, 1946 | Meeting of PRR, Baldwin Locomotive Works and Westinghouse Electric Corporation personnel held in Philadelphia on the proposed Class V1 turbine locomotive; both the Bowes drive and DC transmission are rejected as they would make the locomotive 10-20 feet longer; Carleton K. Steins calls for the coal capacity to be increased from 32.5 tons to 42 tons. (CMP)
Sep. 9, 1946 | Chief of Motive Power Howell T. Cover comments on the proposed contract with Baldwin Locomotive Works for building the Class V1 turbine locomotive, noting that the Bowes drive has been dropped from consideration; he also notes that it is probably that the American Locomotive Company (ALCO) will build an all-welded boiler for the Class Q2, and if so, the same type of boiler, and not a Baldwin riveted boiler, should be used on the V1. (CMP)
Sep. 11, 1946 | PRR Board approves contracting with the Baldwin Locomotive Works and Westinghouse Electric Corporation for the construction of trucks, gearing and drives for the proposed Class V1 turbine locomotive. (VPO, MB)
Oct. 2, 1946 | Chief of Motive Power Howell T. Cover notes some objections to the proposed contract with Baldwin Locomotive Works to build the Class V1 turbine locomotive; Baldwin is demanding to build the boiler, because it knows that the PRR would have an all-welded boiler built by its rival the American Locomotive Company (ALCO); Cover wants the most modern boiler. (CMP)
Nov. 29, 1946 | VP John F. Deasy submits papers to Pres. Clement asking authority to spend $1.15 million to develop one Class V1 modified Triplex 4-8-4-8 coal-burning steam turbine locomotive. (VPO)
Feb. 21, 1947 | General Electric Company issues final report on coal-burning turbo-electric locomotive; was to have been 6,700 HP with estimated cost of $1.15 million each; compares unfavorably with four-unit 6,000 HP diesel at cost of $540,000 each; cost per horsepower $172 for turbine vs. $90 for diesel; concludes that the turbine cannot be competitive, and the project is scrapped. (SMPE)
May 8, 1947 | In a memo to Chief of Motive Power Howell T. Cover, VP James M. Symes kills further development of the V1 Triplex, saying it would be a waste of money. (VPO)
May 14, 1947 | Chief of Motive Power H.T. Cover replies to VP James M. Symes noting that the V1 Triplex would not be a satisfactory freight locomotive as its principal advantage would be in the higher speed range, which the PRR is in no position to attain at present; it would require 7-10 years for development, whereas diesels are presently available; further expenditures would be a waste of money. (VPO)
May 28, 1947 | John V.B. Duer of Mechanical Officers Committee informs other eight railroads participating with PRR in General Electric Company’s steam turbine project that the committee has received copies of all the patents, drawings and test reports, that there will be no further work, and the project is closed. (Rdg)
1948 | PRR cancels further steam locomotive development, including V-1 turbine locomotive, and orders full dieselization
(Bonus) The final nail in the coffin:
Aug. 25 1948 PRR announces expansion of postwar equipment program to $216.7 million; includes 566 diesels, 395 new lightweight passenger cars, 273 rebuilt coaches, parlor, diner and lounge cars, and 4,400 new freight cars; passenger cars are to include 212 sleeping and lounge cars, 118 overnight coaches, 40 diners, including 16 twin-units, and 25 observation and lounge cars without sleeping accommodations; Senator and Congressional to be reequipped with compartment cars. (NYT, RyAge, Guide)
From Wiki: Six of these locomotives were chosen by their designer, Paul W. Kiefer, for the famous 1946 Steam Versus Diesel road trials, where the 6,000 hp (4,500 kW) Niagaras were put up against some 4,000 hp (3,000 kW) diesels (E7's). The locomotives were run along the 928.1 miles (1,493.6 km) from New York (Harmon) to Chicago, via Albany, Syracuse, Rochester, Buffalo, Cleveland, Toledo and Elkhart, and return. The results were close: https://en.wikipedia.org/wiki/New_York_Central_Niagara
I'll admit to skimming over the many replies, but I did not see one mention of the maintainance costs for Steam/VS/ Diesel. Most Modern steam locos would have to visit the roundhouse after every run of at the most of 200 miles. Not to mention the regular boiler washouts, rod lubrication, ash pan clean outs, coaling, watering, pretty much non-stop attention. Then, the upkeep of the lineside facilities for these machines. Now, don't get me wrong.. I think steam was really neat, I love to see them run. However, I see why the RR's dumped them. Simple economics.
Todd
Here is a virtually unknown streamlined Pacific that operated on the Ontario Northland Railway
700 after modifications including streamlining and larger tender. Built with Young valve gear changed to Baker. 200 lbs. 69" drivers. 37% t.e. (with booster 47%) CLC #1692 1921 North Bay 1940's
While I have no specific facts to back this up, I suspect that the "6-4-4-6" arrangement of the S-1 was more for show, than go.. After all, that took a lot of available weight off the driving axles. Add that to the long rigid frame, and it was not a very practical engine. Doomed before it was ever built.
No computers, no phone, no radio. Operating this behemoth was not for your average bear. As strange as this comparison will seem to many it reminds me a lot of the face of an advancing drift underground. Just air, drill oil and water, operating a bouncing jackleg with strength and smarts. High skills at many levels and brawn. No computers, no phone, no radio either. Finishing work at the end of the day the Engineer, Fireman and a two man Mining crew would have a similar appearance. Not for your average bear either.
The Espresso maker is just above the 3 same size circular gauges on the Firemans side.
Overmod http://digital.hagley.org/PRR_11454 Knew if I dug into some of the records, I'd find it. This is the S1 backhead view.
http://digital.hagley.org/PRR_11454
Knew if I dug into some of the records, I'd find it. This is the S1 backhead view.
Such delicate interior! S1 is like a 1925 Rolls-Royce Phantom 1 in my heart.
I found the espresso maker....seats don't look so great.
Estimating steam locomotive horsepowerAuthor: AdamPhillips (2013)
Overmod Note that Elsey's design, as written, is the wrong answer to not just a couple, but several questions nobody asked. It's not particularly hard to understand why it was not applied to the Q1 to 'save' or assist it.
Note that Elsey's design, as written, is the wrong answer to not just a couple, but several questions nobody asked. It's not particularly hard to understand why it was not applied to the Q1 to 'save' or assist it.
I suspect it would be difficult to find someone other than a French mecanicien (as on de Glehn- du Bousquet engines) who would voluntarily choose a system requiring manipulation of four separate controls, without conjugation or indicators of any kind, to synchronize or 'trim' power between two separate cylinder groups. What is needed is a differential arrangement for each control, preferably one which can 'store' the offset needed for slip control, actuate it when needed, and then go back to normal sync or to "best" balance of power between units easily.
If you are familiar with the Eames locomotive, the wacky nature of the throttle arrangement in this patent, as drawn, will be appallingly clear. At high mass flow the steam is NOT going to go neatly between the piping branches; it is also amusing to consider what the flow of combustion gas in the upper flues does to get around the considerable obstruction of the second throttle and interconnections. Elsey appears not to know anything about Wagner throttles or the design of modern multiple front-end (poppet) throttles; there is no room for two of these on a T1 at any point in the available space for steam tracting, and even if there were, it would be better to use air actuators on both and control them from a single grapevine with a fast-acting differential control of some kind appended. We have already discussed practical methods of detecting and indicating the pair of wheels slipping on a duplex -- a pair of simple wheelslip lights representing one of the better ways -- and it is not difficult to design a small motor-activated 'riding cutoff' arrangement (probably applied only to the 'slipperier' engine in practice) that would act in servo to extinguish the lights autonomically.
I do agree with Porta that a better way to eliminate the slip on a duplex is to use four Wagner throttles (Porta couldn't spell very well and called them "Waggoner") which use fluidic amplification for very quick, very close control of fine throttle opening across the full range of actuation. These go immediately upstream of the sets of ports and would be fed by branch manifolds similar to those used on Franklin poppet valves; they allow trim of one engine when the (single) main throttle is fully open and the engine is being driven on cutoff, and don't involve the weight and complexity of a complete separate power reverse arrangement.
The Wagner throttle arrangement is also a more correct way to implement, physically, the differential control as used on the Q2s, as it permits continuous control of the amount of steam admission rather than 'bang-bang' controlling the flow on and off with butterfly valves that require gland seals exposed to nearly full superheat. To my knowledge there was no problem with the actual analog-computer setup used, which remains a highly interesting application of technology to steam power.
Well, that was the problem.
Miningman Baloney! The development of the Diesel engine was true enough but it was 2 and half times costlier to purchase up front. Very expensive. Sizable fleets of Centipedes, Passenger Sharks Bp20's, FM opposed piston entries, Alco PA1's, RF-16 Sharks, even FA1's were a total waste of money and were junk in short order and that after sizeable maintenance headaches, costs, breakdowns and delays. Roundhouse backstops could rebuild, fix and repair steam locomotives quickly and efficiently. Pennsy and NYC would have done better to do exactly what you state the N&W did...hold out until bullitproof proven Diesel locomotives became available, even longer. They succumbed to pressure from a societal direction that was eager for a new world of massive consumerism and easy credit was waved in front of their faces especially by EMD. It was image, style over substance. It did nothing to save them at all, not a thing.
Baloney! The development of the Diesel engine was true enough but it was 2 and half times costlier to purchase up front. Very expensive. Sizable fleets of Centipedes, Passenger Sharks Bp20's, FM opposed piston entries, Alco PA1's, RF-16 Sharks, even FA1's were a total waste of money and were junk in short order and that after sizeable maintenance headaches, costs, breakdowns and delays.
Roundhouse backstops could rebuild, fix and repair steam locomotives quickly and efficiently. Pennsy and NYC would have done better to do exactly what you state the N&W did...hold out until bullitproof proven Diesel locomotives became available, even longer.
They succumbed to pressure from a societal direction that was eager for a new world of massive consumerism and easy credit was waved in front of their faces especially by EMD. It was image, style over substance. It did nothing to save them at all, not a thing.
When you have a motive power fleet that diverse, how can you effectively shop the units for regular maintainance cycles without causing "Havoc" in the "Then-New" Diesel shops? Most of the employees were used to working on steam. Now they have to learn about all these various new critters? Disaster! Well, after about 10-15 years, PRR, along with the rest of them figured out that sticking with one manufacturer (usually EMD ), would simplify life.
Of course you can't forget the Immense savings from eliminating all the coaling/watering facilities, the reduced shop force, etc, etc, etc..
Now, don't get the idea that I hate steam locomotives. I don't. I Love to see the restored ones in operation. But, I will say, if it weren't for the Diesel Locomotive, we would most likely NOT have any railroads left. The modern Semi-Truck would have long ago, stolen ALL the traffic.
Overmod That's not the Centipedes; what you're looking at is the far more significant Essl modular locomotive (which used 408-engined gensets. each with its own little piece of carbody for the radiators, that could relatively easily be swapped out if they failed a la RDC engines, or fired up as needed for instantaneous HP vs. fuel efficiency). That was the first practical 6000hp single-unit diesel locomotive design, the only real problem being that each 750hp unit was arranged to drive on the single adjacent driver axle, giving both control and slipping issues in that era.
M636C"Mar. 2, 1948 VP James M. Symes rejects Charles D. Young’s suggestion for a highpressure water-tube boiler for the S2 turbine locomotive, as the only way to increase turbine efficiency is to use a forced draft, and no fan can stand up to the damage from fly ash and other abrasives. (VPO)"
We should pause here for a moment. There are two kinds of draft in boiler design, forced draft and induced draft, which have specific technical meaning. Very often in railroad practice you see the former term mistakenly used for the latter implementation, as with what Symes is doing here. Induced draft is upstream of the boiler, and the primary air is pulled through the fire, the radiant section, and the convective passes before being exhausted (either through a draft fan or via nozzle ejection as in a traditional front end). Forced draft involves a sealed firebox, and fan arrangements acting as compressors to provide a positive overpressure (and hence greater mass of available oxygen) in the combustion space. Of course, every little hole or seam in the firebox spews gas and soot all the time, which is why forced draft has been a dubious proposition since the early years of steam-locomotive design when it was first tried.
Now you may notice that the B&W high-pressure watertube boiler proposals that culminated in the locomotive design used in the N&W TE-1) will work nicely with induced draft. But not with the draft induced from the S2-style mechanical turbine, with its relatively high slip at low speed, perhaps not even from the V1's two turbines and Bowes drives.
Symes is likely thinking of some of the experimentation with fan drafting, notably MacFarland's. Fans with enough performance to duplicate the effect of conventional front ends that would 'package' in the room available would either have to turn quickly or be very large, in either case exacerbating the impingement wear of exhaust ash and soot on the blading. (It is illustrative to note the ways the South Africans dealt with this through changes in construction and location, a few years later)
An example of railroad use of forced draft is the Velox boiler (described by Duffy in a rather good Newcomen Society paper) which used a gas-turbine compressor to produce (iirc) about 30psi pressure in the combustion air. You can dramatically reduce the size and weight of plant needed for producing a large mass flow of high-pressure steam. But one has to argue that using an expensive, fragile, high-maintenance turbine as a prerequisite for a relatively low-efficiency Rankine cycle plant is a dubious proposition economically -- and I think the Swiss experience thoroughly bore this out.
The US Navy used forced draft in the Destroyer Escorts from DE 1037 Bronstein onward, up through the Knox class until these became known as Frigates and the next class, the FFG-7 went to gas turbine propulsion. My understanding is that these [Navy boilers] were pressurised boilers, with high pressure air being pumped into the combustion space by blowers well downstream of the combustion.
I believe you mean 'upstream' in this context, e.g. pressurized ahead of the air preheaters, with something like Racer pressure burners themselves fed primary compressed primary air.
Of course, these were all oil fired, but coal firing of a pressurised boiler, possibly using pulverised coal injected into the blower stream should be practical.
I'm not sure that's the word I would use for any mobile pulverized-coal plant as by definition you're pressurizing the entire feed apparatus to get it to work reliably, and any failure is likely to result sooner or later in nice coal-dust explosions (which can propagate at about 0.93c, an effect likely to be implicated in the sinkings of the Lusitania and Britannic) and fires where you do not ever want them. Feeding PC with compressed primary air in the burner is one thing; positive overpressure in the firebox something decidedly different.
Now, I have had quite a bit of fun designing locomotives that use a combination of forced and induced draft; the arrangements at the primary end involving a cellular windbox and active dampers to allow fitting a proper combustion-air preheat arrangement and some 'trim' over the fired areas on a grate, but no more than a couple of psi peak overpressure. Even that is probably overkill for most practical road locomotive applications...
Jones1945Looking at the patent drawing of the Baldwin Centipedes, I really can’t understand how they could approve such “vanguard” design;
That's not the Centipedes; what you're looking at is the far more significant Essl modular locomotive (which used 408-engined gensets. each with its own little piece of carbody for the radiators, that could relatively easily be swapped out if they failed a la RDC engines, or fired up as needed for instantaneous HP vs. fuel efficiency). That was the first practical 6000hp single-unit diesel locomotive design, the only real problem being that each 750hp unit was arranged to drive on the single adjacent driver axle, giving both control and slipping issues in that era.
There have been a couple of articles in Trains with good information on this; the principal problem was that it was even more expensive than the equivalent hp's worth of building-block EMDs ... and that proved more important than the length reduction (this design offering considerably more than a 4-unit FT hp in only about 58' length; see Kiefer's 1947 report for the packaging advantages).
PRR's Centipedes were built with those DeLaVergne tugboat derived engines, taking four of them in two units to match Essl's prospective output. This was considered (by Baldwin and PRR) to be a better capital and maintenance prospect, the engines peaking at only 625rpm with everything overbuilt. (If you argue, consider how R.J. Russell, who ran BP-20s on the Bay Head trains, got normal high acceleration -- he said the ammeter would go into the red and peg, and only come floating down after a minute or so, stop after stop. And PRR only retired those units when it consolidated the number of types of locomotive power after 1963...
M636C ……My understanding is that these were pressurised boilers, with high pressure air being pumped into the combustion space by blowers well downstream of the combustion. Of course, these were all oil fired, but coal firing of a pressurised boiler, possibly using pulverised coal injected into the blower stream should be practical. At least there were no turbine blades to erode, just the water tubes......
Backshop Since nothing happens in a vacuum, what else is happening in the railroad world at this time... Other railroads have dieselized and laid off thousands of employees and closed multiple heavy maintenance facilities. They have also stopped their dependence on the whims of the most powerful labor union of the time (UMW). Even if the PRR gets the duplexes sorted out, so what? Most are for passenger trains, which although they are prestigious, don't make any money. What are you going to do to replace those thousands of H,K,I,M,and L classes worn out from the war. The only reason the Pennsy wasn't swamped by the war was all the steamers not needed by the new electrification. Now, they are antiques.
Since nothing happens in a vacuum, what else is happening in the railroad world at this time... Other railroads have dieselized and laid off thousands of employees and closed multiple heavy maintenance facilities. They have also stopped their dependence on the whims of the most powerful labor union of the time (UMW). Even if the PRR gets the duplexes sorted out, so what? Most are for passenger trains, which although they are prestigious, don't make any money. What are you going to do to replace those thousands of H,K,I,M,and L classes worn out from the war. The only reason the Pennsy wasn't swamped by the war was all the steamers not needed by the new electrification. Now, they are antiques.
rcdryeA key to the diesel transition was the MU building block principal. Once labor agreements allowed MU operation it became possible to build a 6000 HP diesel that could still operate if one of the units went off line. If your 9000 HP turbine drops out, you're in real trouble. PRR's side trip with the Baldwin Centipedes shows how deeply the "Big Engine" mentatlity was embedded in both builders and carriers. Santa Fe's largely unnoticed, but nonetheless groundbreaking decision to order all of its FT units with couplers instead of drawbars hastened the end of steam as much as anything.
“Feb 24, 1948 Charles D. Young writes to James M. Symes calling attention to an article on turbine locomotives in the Feb. 14 issue of Railway Age and suggests inviting Westinghouse Electric Corporation and Babcock & Wilcox to collaborate on a design for a high-pressure water-tube boiler for the Class S2 6-8-6 chassis. (VPO)”"Mar. 2, 1948 VP James M. Symes rejects Charles D. Young’s suggestion for a highpressure water-tube boiler for the S2 turbine locomotive, as the only way to increase turbine efficiency is to use a forced draft, and no fan can stand up to the damage from fly ash and other abrasives. (VPO)"
The US Navy used forced draft in the Destroyer Escorts from DE 1037 Bronstein onward, up through the Knox class until these became known as Frigates and the next class, the FFG-7 went to gas turbine propulsion.
My understanding is that these were pressurised boilers, with high pressure air being pumped into the combustion space by blowers well downstream of the combustion. Of course, these were all oil fired, but coal firing of a pressurised boiler, possibly using pulverised coal injected into the blower stream should be practical. At least there were no turbine blades to erode, just the water tubes...
These installations were very compact for their power, 600psi and 22000 shp in the Bronstein and 1200psi and 35000 shp in the Knox.
Of course the 40000 shp in the FFG-7 from two GE LM2500s was even more compact and not that much less fuel efficient, since you could run on one turbine and extract waste heat for dometic purposes. You could also run on one boiler in the steam ships, of course, but they had only one steam turbine which was a single point of failure.
These ships are about ten to fifteen years later than the rail steam turbines being discussed, but the US Navy is rarely at the forefront of technology (nuclear power excepted).
Peter
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