-=> Quoting Alec Cameron to Reggie Arford <=-
 AC> HI Reggie
 AC> On (02 Jul 97) Reggie Arford wrote to Gregory Procter...
 AC> But, some of your comments to him were aimed at my message so I will
 AC> add to the discussion:
 RA> You are misapplying the term "comparable horsepower".
 AC> I think I used that noxious term because it was in Gregory's message.
 AC>
 AC> Remember,
 RA> steam locos do not have "a" rated horsepower as a Diesel does;
 RA> they cannot.
Of course steam locos can have their horse-power measured at the drawbar, 
ust
as a Diesel or electric can! Certainly the rated horsepower of a US built 
Diesel
is that of the prime mover (the Diesel motor itself) but it is the power at 
the
rails that gets the work done, whatever the motive power. The problem was, 
nd
generally still is, that there were (almost) no dynometers big enough to 
measure
the outputs of the majority of steamers. Dynometer cars were common enough 
ut
they could not measure constant outputs due to inconsistant track conditions.
A big difference with steam locos is that their short term output was much
greater than their continuous output, while a Diesel might have a 10-20% 
hort
term increase.
As any motor turns faster, its power increases (up
 RA> to a point).    ^^^
 AC> Quite wrong! Most electric motors [both AC and DC] reduce in power
 ...........
 AC> output as the speed increases. For loco installations, external
 AC> second "one hour" rating. *Very* roughly, maximum drive power is
 AC> available at half maximum speed. For AC induction motors [the most
 AC> common of all industrial motors] maximum drive power is at near 85% max
 AC> speed.
 I'll largely go along with that. Some railways also apply a higher 10 minute
 rating as well.
 RA> Why? A Beyer-Garatt (sp?) type engine, perhaps burning
 RA> pulverized coal or a coal/water slurry, would work quite nicely.
 RA> Note that on a steam loco, the axles are usually MUCH closer
 RA> together, so a 4-coupled steamer may have a similar rigid
 RA> wheelbase to a C-type (3 axle) traction truck.
 AC> These two versions of "rigid" wheelbase can hardly be compared because
 AC> the springing of the individual axles on the C- type track assures more
 AC> constant force on the wheels, than is possible with the steamer.
Why compare technologies that are 100 odd years apart?
The differences in springing you mention are due to individually sprung axles
on the steamer, compared to equallised suspension and two stage springing on
your Co'Co'. Plenty of steam locos had equalisation in conjunction with their
springing. eg the "American" type from the 1840's on, right up to the last of
the French and German types around 1950s. (I must admit to not knowing how 
he
USRA types were sprung)
Over
 AC> rough track [is there any other kind?? ]  the rigid steam drivers
 AC> will often have two or more wheels barely in contact with the rails, as
 AC> the loco shimmies and bumps.
I have a video of the German ICE from the cab, a coin on edge on the consol
doesn't move at 400Km/hr.
The C- truck is far from rigid, one axle
 AC> may rise while its partner falls, thus maintaining hefty contact with
 AC> the [slippery?] rail. A bit like independent front suspension on an
 AC> auto, versus beam axle.
The same thing can, and has been done with steam locos.
 RA> there were several types of articulated steam loco used on the
 RA> "trench" railroads. Some 0-6-0 locos had a ZERO rigid wheelbase!
 RA> These mechanisms could be adapted to modern use. A more powerful
 RA> steam locomotive could replace several MUed Diesel units.
 AC> Well, this is theory and dreamtime. The steam loco was killed by
 AC> rising standards of living, higher wages, necessity for high
 AC> productivity. The proper place for a steam loco today is in a museum.
Yes, well that's where we started, considering if it was practical to bring 
back
the steam locomotive, either in its old form, or with a 1997 design.
I suggested that by using present day technology and design, a steamer could 
be
practical under the right conditions.
We, (and I include the USA, Europe, the UK and NZ etc.) have an overall drop 
in
living standards, lower average wages, ever increasing unemployment and an
ideological cry for higher productivity from less and less workers over the 
last
few years. As total production falls year by year, either we accept the
increasing problems and social costs of more and more unproductive people
dragging down the rest, or we come up with a new ideology to allow them to 
work
at differently productive tasks. There are several other alternatives, but
Adolf, Idi and co. aren't generally popular at present!
The old designs are still in use in India and China, probably still being 
built!
No, I don't think that steamers will come back, but I do think that
theoretically they could make sense in a few places. Here in NZ we have large
supplies of coal which are dug up and dragged to the port by Diesels. The 
oal
is then burned in Japan to produce electricity. Imported Diesels burn 
mported
oil using the lowest possible number of employees, while a high proportion of
locals sit unemployed.
Sorry to get so close to politics, but they are a part of life. The WC now 
wn
our railroad, and the entire WC organisation probably has a bigger budget 
han
NZ's, so perhaps Railroads = Politics?
Greg.P.
Christchurch,
New Zealand.
  
... Catch the Blue Wave!
--- FMail 1.02
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