Obvios answer I've missed?

[Charlie Free]

Hello all,

OK, please be nice on answers to this question, it is probably obvious, but I've missed it somewhere. Other than buying a book on a specific steam model like the Penn Switcher, or Shay or whatever, is there a good source of already scaled plans for a generic Atlantic 442 somewhere? Do you acquire a copy of original builders blueprints and scale it down yourself? Where exactly is the holy grail of plans for 1 1/2" locomotives. Over the years I have accumulated a number of books covering all the basics of construction and techniques, but the actual source of dimensions is no where to be found. I know certain things can be scaled down proportionally, but many cannot, like axle sizes, bolt patterns, structural supports, but where is the safety correction factor for critical parts. Thanks for any help.

Charlie Free in NC

[GWRdriver]

Charlie,
For better or worse, the way it has been done is that some capable and knowledgable person, either for their own enjoyment, for the good of mankind, or for profit, has taken it upon him or herself to create a model locomotive design and those are what we have available today. For a 7.5"ga Atlantic specifically, I know of only two designs where ready-to-build drawings are avalable . . . the Martin Lewis Little Engines Atlantic, which was originally based upon a Harriman SP prototype and actually a shortened SP Pacific, and the Saturated Steam/Brien Gittins Pennsy E-6 Atlantic (1.6" scale) serialized in Modetec magazine. There are a couple of British Atlantics but I wouldn't supposed you are interested in those.

Using the basic details of the Little Engines design one could rework this into another "species" of loco other than an SP although it would be difficult to say convert it to a true USRA design without a lot of reworking. Revising the E-6 design, which is highly detailed and specialized, and Pennsy which was unlike anything else, into something else would involve so much work as to be impractical IMHO. One might also take one of the various 7.5"ga renditions of the Souhtern Rwy PS-4 Pacific, a USRA prototype, and shorten it to an Atlantic, but then so far as I know the USRA produce no Atlantics.

There are very good Atlantic design in 3/4" and 1" scales and a clever person could, with adjustments for scaling, enlarge these to come up with a 7.5"ga version. However some areas would not scale up proportionately and one would need to have some knowledge and understanding of the design differences that only one step up (or down) in scale would present.

In all this talk of books and magazines I have forgotten to mention that I have found (IMHE) that no one book, or magazine, or volumes of magazines, contains all you will need to know. It takes a village of resources, so to speak, to provide a broad education in live steam.

As far as developing a design from prototype drawings, for personal or club use as opposed to say creating an exhibition model which is intended to compete for dishwear (a championship cup), several things generally apply. First virtualy nothing of the construction detail of the prototype is retained because We in live steam have our own language, our own lexicon, of design details and practice which are proven to work. Sure they appear and behave somewhat like the prototype, like the boiler for instance, but very few if any construction details can be lifted directly from the prototype and be successful and reliable.

It's difficult to describe briefly, but rather than deduce or reduce a design from the prototype, what we generally do is begin a constructive process, where the "envelope" or outline of the model is established based upon the dimensions of the prototype. How closely one stays to the original dimensions and proportions is up to the designer or builder. Once we have established the "envelope" we set aside the prototype drawings and using the language and technology of model live steam we add structures, components, and details one at a time until we have a complete locomotive design which looks like the prototype on the outside but is a substantially different animal on the inside.

There are occasional exceptions to these guidelines, valve gear design for instance, what is good for full size works just as well for us, in fact we have no other alternative than to apply full size practice to valve gears, however what is sure to be different is the details of construction and component parts.

I hope this is a start in answering your questions but this is a vast subject and difficult to gloss over in a few paragraphs.


[This message has been edited by GWRdriver (edited 08-04-2006).]

[fred v]

http://steamcad.railfan.net/
no Atlantic but some stuff to look at.
http://www.catskillarchive.com/rrextra/Page0002.Html
lots of articles on how the full size was built.
fred v

[Bill Shields]

You can do what Jim did for his B&M Atlantic...purchse a set of erection drawings, which are 1/8 scale to begin with and build from there.

I did that with my NYC Hudson tender...

Drawngs are still available from many of the respective historical societies.

Alternatively, if you are very creative and don't care about exact replication of a prototype, you can work from photographs and kit-bash something together.

[This message has been edited by Bill Shields (edited 08-04-2006).]

[phty95014]

Harry, lots of good sage advice there.

Fred, much thanks for the links. I've
bookmarked them for future reference.

Bill, where does one get erection drawings?

Enquiring minds want to know....

Pat Y.

[Bill Shields]

Erection cards / drawings are still available from many of the respective railroad historical societies around the country.

http://www.nycshs.org/
http://library.uml.edu/clh/bmarch.html

Another good (commecial) source is

http://www.livesteamlocomotives.com

They have many plans available listed on their site.

Also, lest I forget

http://steamcad.railfan.net/lima.htm



[This message has been edited by Bill Shields (edited 08-07-2006).]

[GWRdriver]

Pat,
Depending upon the depth of detail one wants to achieve in a model an "erection" drawing will have the most detail and information, far more than you will probably need, but these can sometimes be difficult and expensive to get, if they exist at all. There are a couple of perfectly acceptable alternatives. Over the years Model Railroader Magazine (as one example) and to a lesser extent Railroad Model Craftsman, published 1000's of sets of superb drawings of American locomotives, the best of which were done for Model Railroader by "Gike" . . . Harold Geisel, who was a retired architect.

Narrow Gauge Gazette likewise over the years has published 1000's of sets of detailed drawings of narrow gauge locomotives. Most of these are crisp, superbly-drawn images with sufficient dimensional and detail information to build fine models, which was of course their purpose.

"Builders cards" are different from erection drawings in that they were around file-card size and had only the barest minimum of dimension and detail, rarely enough to do a good job of developing a design, but they did establish basic dimensions such as wheelbase, wheel diameter, boiler diameters, and overall dimensions. Tractive effort and wheel loading were also usually included but those figures don't do us much good.


[This message has been edited by GWRdriver (edited 08-07-2006).]