Subject:
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Re: Dimensions of a SD40 and GP35
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Newsgroups:
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lugnet.trains
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Date:
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Thu, 2 Dec 1999 14:41:27 GMT
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Reply-To:
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lpieniazek@novera.com!AvoidSpam!
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Viewed:
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786 times
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Christopher Masi wrote:
>
> My thinking was this:
<snipped some good analysis>
> why would a rail road
> company do put a GP and an SD model together?
The people who order power are usually thinking strategically, that is,
what is the mix of loads, the track weight capability, the grades, etc,
and how is it going to change over the 20+ year service life of a loco?
So they order SDs (or other C truck locos) for high horsepower low track
loading situations and GPs (or other B truck locos) for lower horsepower
higher track loading situations.
The people who dispatch power (the Power Desk) are thinking tactically:
I need this many HP, what do I have on the ready track right now, and
what other needs are there going to be before I get more engines out of
service from incoming trains?
Therefore you see wild stuff in the same lashup. When a road is in
desparate straights (harvest season on the grangers, UP for the last two
years, basically) anything goes.
If they needed the six wheel SD
> why would they be buying a four wheel GP. Anyway, I decided to model a second
> engine. The second engine had to be a four wheel per truck engine, and smaller
> than the SD 40. The other pictures in the book I have (there are many other
> pictures, but I was looking for the classic America freight diesel) are the GP
> 38-2 and a GP 9. So, I figured that the GP 38 was the way to go. So, I asked
> for the dimensions of the wrong engine, but Larry uncovered the informtation
> that I was really looking for; that is, as long as the GP and SD series of a
> particular model share the same platform.
No, don't draw that general of a generalization. Go to a good public
library and get a copy of the cyclopedia out, it has lots of drawings.
The platform sharing we were talking about was only within the SD line.
Also, the dash-2s were a special case of numbering breaking down. GM
liked the model numbers they had and were trying to show that they were
just improving things but in actuality, in a lot of cases it was major,
frame up redesign, with wild differences. There should be no implication
that a GP38 and a GP38-2 for example share anything dimensionally.
> When I put pictures up, which should be
> reasonably soon, I'll detail the trucks.
Can't wait. I never build dummy locos, I should start, that's the only
way to achieve proper truck spacing...
> P.S. What does the P stand for in the SD"P" 40. Is the steam for passenger
> trains (ahh that could be why the P is there)?
Yes. P is for Passenger. GM model designations are screwy, but that's
usually what P means... The SDP40 has a steam generator. Older passenger
cars are steam powered, they use steam turbines to generate electricity,
and steam ejectors to generate air conditioning, and steam heat for
heating. Newer passenger cars have HEP (Head End Power) or electric
versions of all those things.
So newer locos, now that the heritage fleet is pretty much gone, don't
have steam generators any more, they have auxiliary generators, or some
other arrangement for tapping into the main generator (and reducing the
HP that gets to the rails) to supply the train with electricity.
One of the main reasons (other than Raymond Loewy) that Es are longer
than Fs (these are the older diesels, so called covered wagons or cowls,
although technically they weren't cowls because the body provided
structural strength, which are faired all the way back) is to house
steam generators.
--
Larry Pieniazek larryp@novera.com http://my.voyager.net/lar
- - - Web Application Integration! http://www.novera.com
fund Lugnet(tm): http://www.ebates.com/ ref: lar, 1/2 $$ to lugnet.
NOTE: Soon to be lpieniazek@tsisoft.com :-)
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Message has 1 Reply:
 | | Re: Dimensions of a SD40 and GP35
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| Thanks Larry, Looks like I'll have to head to the library. Before I try to build the power unit. Your "ersatz Alco" is that Big Red, the engine featured on your web page? Chris <snip everything Larry and I typed previously> (25 years ago, 2-Dec-99, to lugnet.trains)
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Message is in Reply To:
| | Re: Dimensions of a SD40 and GP35
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| My thinking was this: I did not want to give up on the SD 40-2 because of the six wheel per truck issue, but I knew I would need a four wheel per truck to provide power for my train if I made the SD 40-2 a dummy engine which I did to make the six (...) (25 years ago, 2-Dec-99, to lugnet.trains)
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