economic case for high speed steam

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From:	"wholelephant" Add to Address Book Add Mobile Alert
Date:	Tue, 15 Aug 2006 16:02:47 -0000
Subject:	[steam_tech] economic case for high speed steam

EXTENDING THE ARGUMENT
Mark Twain spoke of a cat that once jumped on a hot stove and
never again jumped on a stove again. Experience is the best
teacher, but it can be the worst teacher too, if not properly
analyzed. There is nothing so dangerous as a half-truth. If you
have to think outside the box all the time, your box is too small.
Let's see how these little profoundities apply in the railroad
industry, one example, anyway.
High-speed steam was indeed misused in low-speed service,
per Ed King's article (September 2004), perhaps the definitive
piece on the point. The N&W Y-6b would have been far more
economical in the 20 mph service performed by numerous high
wheel, high horsepower locomotives. There it might have held
off the diesel, at least a bit longer. Like, nevertheless, Bill
Withuhn's otherwise superb June 1974 article on steam
scrapped too soon, it only points a finger at poor drag freight
performance. In this same vein, the stillborn ACE project of the
1980s was a GP40 substitute aimed at the diesel's strong hold,
drag freight. King's superficial overview of diesels was, again,
aimed only at drag freight effectiveness. It did not deal with their
fundamental problems, and, minor points excepted, broke no
new ground. The article is a lot of shoulda coulda woulda without
extending the argument:
Super-Power came along four decades ahead of its real market
for speed.
The railroads dieselized on fast, light trains and slow, heavy
trains, on which the diesel's advantages were most apparent.
This engrossing experience left the industry and observers
ill-equipped to cope with the fast, heavy trains that came a
decade or so afterwards. Electrification was briefly touted; at
least the catenary's abundant power would not have left traction
motors starved at speed by constant horsepower mobile
generation.
Modern steam's advantages were lost in a lot of "everybody
knows."
Let's boil this down to one practical, but still current, question:
What if the New York Central Niagaras had lasted long enough
to be used on Flexi-Van trains, instead of being relegated to drag
freights and scrapped less than five years before?
On the one hand, the Niagaras were deliberately designed with
more power than necessary. At 60 mph the "standard" Niagara
was considerably more powerful than a three unit 6000 hp E7, if
indeed less powerful at 30 mph. Not only that, it was actually
less expensive to operate. It could also keep pace with the
diesel's long locomotive runs and utilization. Niagaras were built
with poppet valves, a longer combustion chamber, and higher
steam pressure, although not on the same locomotive. The little
tried Geisl exhaust was also available. (TRAINS, March 1984)
On the other hand the average freight train speed in the
dieselization decade, 1945-1955, was 17 mph. (TRAINS, June
1974) At such speeds the constant horsepower diesel-electric is
in its own element. All that power is available as long as the
wheels do not slip or the traction motors burn up. Freight diesels
geared for 65 mph could develop their full horsepower at 10 or
12 mph. Rather few modern steamers were designed to operate
efficiently under 40 mph, the Y6b being a notable exception. The
diesel is indeed a terrific drag freight locomotive, coming when
the railroads were still a drag freight operation, two decades of
Super-Power notwithstanding.
Although the early streamliners gave the diesel an image of
speed, the constant horsepower diesel has a severe problem
on fast, heavy trains. That abundant tractive effort at low speed
falls rapidly in the middle range and tapers off to a dribble in the
upper ranges. Remember the xy=k or y=k/x curves in first year
algebra? That is what you get when speed x tractive effort equals
a constant horsepower.
It was well known in early dieselization that comparable
steamers were more powerful above 25 mph or so, but this was
well forgotten when it would have made a difference. With the
blossoming of fast intermodal traffic in the early 1960's the newly
dieselized railroads had a problem. Flexi-Vans soaked up power
in "elephantine" proportions. So said an October 1962 TRAINS
photo section caption of five GP20s, a GP9, and an F7, 13,250
hp., on a Flexi-Van. The point was not totally obscure. Jerry
Pinkepank's article on electrification recorded it for posterity, July
1970 TRAINS:
"Probably the biggest factor causing renewed interest in
electrification is the delayed reaction now taking place on the
railroads regarding the costs of the freight-train speed-up of the
1960's. When the railroads shifted off 1-horsepower- per-ton
locomotive ratios and began buying super-diesels for hypoed
freight schedules, they entered a new era in costs. Piling on the
units- even after `unit reduction' resulting from use of 3000
h.p.-plus locomotives- also piles on the expenses for fuel and
locomotive and maintenance costs..."
Robert Le Massena amplified the point in TRAINS, January
1974, noting EMD's venture into electrification as its recognition
of the problem:
"... In terms of diesel-electric propulsion, the price of speed is
too great. On level, tangent track in fair weather, a single 3600
h.p. SD45 unit can just maintain 35 mph with 5000 tons. Two
SD45's are needed for 51 mph, and three units are required at
62 mph. Four times as many units must be used at twice the 35
mph pace..."
Second generation diesels had a horsepower race that ran its
course by the early 1970s. By 1976 it was not enough to save
Santa Fe's Super C intermodal, on a 40 hr. Chicago-LA
passenger schedule, from needing twice the diesel horsepower
at 70 mph as at 50. The diesels "crapped out" at speed on test
runs. (TRAINS, May 1986)
In TRAINS, April 1990, Gary Dolzall explained the dire squeeze
between high speed cost and truck competitive pricing. Santa Fe
had concluded that Super C's 6hp/ton and 79 mph running were
uneconomic well before the Kuwait crisis surcharges:
"Another way to guage what's hot in Santa Fe's stable is the
horsepower-to- ton ratio that the System Operation Center (SOC)
in Chicago assigns trains. Nos. 199 and 991 generally get about
5 horsepower per ton; trains like 188, 189, 198, 891 and the
transcon Q-trains get about 4. In comparison, a priority freight or
lesser intermodal train will be assigned about 2.5 or 3 hp/ton;
Santa Fe's doublestackers get a little over 2, and a typical unit
coal train in flatland territory gets perhaps 1.2.
"Indeed, the real key for AT&SF is to be consistently truck
competitive- not only in speed, but in pricing... there is no simple
answer to what the market pays. But as a ballpark figure, you can
guess the 'street rate' (i.e., no discount) rate for a 45 foot trailer
moving from Corwith to the West Coast at something over
$1,300; a container on a stack train will probably be $200 less.
Those kinds of rates... largely preclude the fuel bills which would
correspond to Super C's 79 mph running and locomotive
assignments over 6 horsepower per ton. Nonetheless, Santa Fe
intermodals do still roll along at 70 mph. Certainly, part of the
reason AT&SF's operating ratio is high is that intermodal traffic is
both service-intensive and ultra price-competitive, and that
combination, no matter how well- oiled the machinery, inevitably
closes the gap between operating revenues and operating
costs."
The route's fastest freight timing lately is over 51 hours, today's
limit, not of physical, but of economic reality. (TRAINS, November
2000)
The railroads still have a problem. In 1989 Thomas Finkbiner,
Norfolk Southern VP-intermodal, said all the new doublestacks,
skeleton cars, Roadrailers, etc., were essentially scrap metal
unless they could average 55 mph instead of 25 (a decade and
a half later, barely 20). (Modern Railroads, November 1989)
The new AC locomotives are terrific at 10 mph, at half again the
capital cost. That might be fine for captive bulk traffic, but they
have no significant advantage for speed competitive, marginal
intermodal traffic.
Mobile generation still requires four to six times the generating
capacity used at any given time, based upon the WW II Pennsy
study that the central power plant load was generally 16% of the
total electric fleet horsepower and never more than 22%.
(Barriger's foreword, Middleton, When the Steam Roads
Electrified) That is a lot of excess, unusable capacity, AC or DC.
See Insull's nineteenth century argument, that centralized power
accomodates peak loads occuring at different times and allows
a smaller total capacity. For all the dizzy changes elsewhere,
Pinkepank's 1970 article could be updated in the proverbial
twenty-five words or less, notably that any fixed railroad
investment is difficult now.
Could the Niagara have revised locomotive economics four and
a half decades ago? And, in turn, the intermodal industry? It was
too powerful for the NYC passenger trains of the late 1940s, but
the Flexi-Vans a decade later would have been just the outlet for
its excess energy.
Would we still be using Niagaras today? Perhaps so, as
stagnant as motive pwer thinking can be at times. Even the
Niagara, however, did not exploit such technology as four
cylinder divided drive, high speed compounding, and double
Belpaire fireboxes, which would have increased performance at
both high speed and low. (TRAINS, June 1974)
Or a turbine. Contemporary with the Niagara was the
Pennsylvania' s direct drive S2 steam turbine. It was marvelously
efficient at speed, but was scrapped because of a leaky boiler.
(Pennypacker, Pennsy Power) As I diagnose the problem over a
half-century later, it drained the boiler at low speeds, at which a
deflection displacement turbine is little more than a hole in the
boiler, causing a drastic pressure drop, boiler contractions, and
leaks. Such a simple expedient as a reverse gear for the small
reverse turbine, however, would have let it start the train and let
the larger one cut in at proper speed. It exhausted steam at
barely atmospheric pressure, ready to condense and be reused,
also indicating a high thermal efficiency. A King Kong booster
might get a new turbine up to 20 or 30 mph, or perhaps a split
drive torque converter would allow the turbine proper rpm at low
speed. Coal fired steam turbines generate most of our electricity
today but no one wants to dieselize them.
How about a Garratt, perhaps, with as unconstrained a boiler
and unobstructed a firebox as is possible on standard guage
rails? With twice the grate area of a 6,000 hp articulated, it would
have twice the horsepower. If we can double the boiler pressure,
a big "if," to be sure, we would double the power again.
Average 55 mph? How about 100? Higher speeds generally
would be one approach to the new rail undercapacity problem,
the old overcapacity problem having been solved about a decade
ago. There is a lot more to fast, reliable rail service than
over-the-road speed, and more to that than motive power, to be
sure, but this is the real market for new Super-Power, now eight
decades later.
P.S. How about industrial hemp as a possible external
combustion biomass fuel and possible crop for the badlands?
Figure the rough, open, contiuous fires of external combustion
are far less finicky about fuel than the closed, precisely
machined, often intermittent fires of internal combustion, thus
much more easily satisfied with some less expensive and
environmentally damaging product from tar sands or oil shale?
How about sulphur-eating bacteria, per PBS nature special on
formation of caverns out west?
P.P.S. In some 48,000 postings there does not seem to be any
discussion of H.F. Brown, "Economic Results of Diesel Electric
Motive Power on the Railways of the United States of America,"
Institution of Mechanical Engineers, London, editorialized upon
in TRAINS, March 1961. I have a copy of the published
proceedings with a lively discussion afterwards (as opposed to
the occasional advance copy). Brown, with railroad experience
going back to the New Haven electrification of 1905, argued the
railroads made money on diesel switchers but lost money on
diesel road locomotives.
William F. Wendt, Jr