Fwd: [steam_tech] DPM convincing?

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--- On Tue, 3/18/08, wholelephant at yahoo.com <wholelephant at yahoo.com> wrote:


> From: wholelephant at yahoo.com <wholelephant at yahoo.com>

> Subject: Fwd: [steam_tech] DPM convincing?

> To: 

> Date: Tuesday, March 18, 2008, 3:27 PM

> william wendt <wholelephant at yahoo.com> wrote:  To:

> steam_tech at yahoogroups.com

> From: william wendt <wholelephant at yahoo.com>

> Date: Thu, 21 Feb 2008 09:38:40 -0800 (PST)

> Subject: [steam_tech] DPM convincing?

> 

>         Was DPM's March 1961 editorial, Impressive But

> Not Convincing, on the H F Brown paper the last shot of the

> old steam-diesel debate?

> 

> Or is it a sleeping dog that has lain far too long?

> 

> After listing several of Brown's contentions and

> leaving specific rebuttal to "more qualified pencil

> pushers" DPM rested his case largely on this one

> paragraph:

> 

> "We regard Mr. Brown's paper as impressive but not

> convincing. For example, the merits of 'modern steam

> power' are better illustrated in specific applications

> than in over-all comparisons. It is true that Missabe Road

> 2-8-8-4's moved ore trains of almost 18,000 tons gross

> off the range and that N&W 2-6-6-4's managed

> 14,500-ton coal drags in flatland running. The equivalent,

> say, of perhaps three six motor, 1750 h.p. diesels. Driver

> axle loadings in this example range from slightly less than

> 50,000 pounds for the diesel to 70,600 pounds for the

> 2-8-8-4 and on up to 107,525 pounds for the 2-6-6-4.

> Clearances favor the diesel, too, as does the fact that the

> articulateds are indivisible. Put it this way: How many

> roads possess N&W's physical plant? Again, even

> N&W found it necessary to manufacture two basic types

> of steam locomotives (simple 2-6-6-4 and compound 2-8-8-2)

> to operate in mountain and flat terrain on the merchandise

> trains that are now handled by multiples of a single type

> of diesel, a unit of which is also at home, say, on the

> Abingdon Branch, where foremerly a 4-8-0 was the largest

> type of power assignable."

> 

> DPM's pencil pushing is pretty much straight arrow on

> the DMIR application, judging by his own Steam's Finest

> Hour, p57, listing 565,000 WOD for the 2-8-8-4, and the

> November 1959 TRAINS on DMIR. Figure six motor units of the

> time commonly had 50,000 lb axle loads.

> 

> Re the N&W application, however, he is strictly pencil

> pushy. His own SFH, p67, lists 432,200 WOD for the Class A,

> which, divided by six, is actually less that the 2-8-8-4

> figure. 

> 

> Figure also the "single type" of diesel on the

> N&W was four motor units from two builders. Further,

> that four motor mainline freight units ran from 120 to 130

> tons, or 60,000 to 65,000 lb. axle loadings, whatever the

> specific N&W figures were. 

> 

> Three SD9s would have replaced the A? Again, his own SFH,

> pp61, 66, says it averaged over 30 mph start to top with

> those 14,500 ton trains and did twice that with 125 cars of

> merchandise.

> 

> By EMD figures relayed by LeMassena, January 1974, the 3600

> hp SD45 could haul a 5000 ton train on level tangent track

> at 35 mph, two at 51 mph, three at 62 mph, and four at 70

> mph. 

> 

> By these figures, it would have taken three SD45s to make

> those 14,500 ton hauls, twice the hp of the DMIR units. 

> 

> But figure the 125 cars of merchandise averaged 60 tons

> each, for a train weight of 7500 tons. That is almost half

> again what three SD45s were hauling at that speed, or four

> and a half units.

> 

> There is a lack of record what the Class A could haul at 60

> mph. As I wrote in my mini-review of Ed King's not quite

> complete account of the A, 

> 

> "On test the A hauled 7500 tons at 64 mph, King

> reports without elaboration. Figuring that three SD45s can

> haul a 5000 ton train at 62 mph per EMD figures, this

> performance is the equivalent of 4 1/2 SD45s. 

> 

> "This figure has since been questioned as a misprint

> by Le Massena, Mainline Modeler, July 1993...."

> 

> "On freight runs they cruised at 60 mph, often with

> consists filled out to 8000 tons. On one run they covered

> 92 miles in two hours. The conditions could be a bit more

> wonderfully completely described, however." 

> 

> Impressive, and maybe even convincing, by DPM's own

> words then, is that the diesel is not quite the all-around

> motive power he thought. Actually, he did notice in the Oct

> 1956 issue that steam seemed to last longer on high speed

> flatland operations than on mountain pikes. And a footnote

> in the Lima diesel article, Nov 1963, referring to

> Brown's paper, said Lima could hardly be blamed for

> taking the diesel's fast freight performance as less

> than impressive. 

> 

> Rather than deprecate N&W's superb realization of

> the different requirements for slow and high speed power,

> DPM might have better questioned why PRR did not order 25

> Y-6bs for the mountains and 100 As for the flatlands,

> instead of the redoubtable but not quite equal C&O T-1.

> What if it had not ordered the 25 Q-2's, a possibly

> superb 80 mph machine with proper attention to detail, but

> Class As instead? The Q-2 had no significant advantage over

> the J-1 under 50 mph, but significant disadvantages. Staufer

> and Pennypacker, Pennsy Power bemoans the order of 100 K4s

> instead of M1s, a better explanation of why not so much

> steam, but its implementation, failed.

> 

> The N&W was the notable exception, of course, its

> 2-8-8-2 coming within a whisker of the four unit souped up

> 7000 hp F7 on 1% grades, performance and cost-wise, and at

> a much lower capital cost. Actually, as far as that goes,

> that same F7 came within a whisker of the A's

> performance on those 14,500 ton coal trains, leaving me to

> wonder where all that extra hp of the three SD45s goes.

> Actually, I have been wondering for about 35 years, since

> moving a block from the C&NW mainline, observing three

> unit SD40s on both 12,000 ton unit trains and fast

> piggybackers, and reading SFH on the A's exploits. 

> 

> And that Nov 1959 article on the DMIR noted the three unit

> diesel could start a heavier train, but the Yellowstone

> could pull a train it could start faster than the diesels.

> That same issue has DPM's own observation on a PRR T-1

> cab ride, that the great racer literaly SURGED when the

> throttle was opened at 70 mph, his emphasis. Contrast that

> with the May 1986 article on the Super C, the diesels

> crapping out at speed. 

> 

> The closer analysis should be impressive and convincing

> both. That is, if it is properly expressed in accounting

> terms, not merely performance figures. 

>   Does anyone know, then, 

> 

>   1) how big a train the A could haul at 60 mph? What

> happened to N&W fast freights after dieselization? 

>    

> Figure this is the more critical figure today than the

> decade of dieselization, when the diesel's advantages

> on slow, heavy trains and fast light trains were more

> decisive. The speed limit today comes from the expense of

> fuel on fast freights. It is well documented in the pages of

> TRAINS if little realized that diesels are very, very

> expensive on fast, heavy trains, 5 hp/ton being about the

> economic limit. July 1970, January 1974, May 1986, April

> 1990. The Niagara was both more powerful at 60 mph than a

> 6000 hp E7 and cost less to operate, per March 1984

> article. Too bad one was never tried on a Flexi-Van.

> 

>   2) How fast could a 2400 hp SD24 or 2500 hp SD35 haul

> 5,000 tons on level tangent track?



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