Prototype Fidelity Versus Practical Reality

The current issue of O Scale Resource magazine contains an article which will be the first of a series on scratch building locomotives in O Scale. Glenn Guerra is starting the builds as will be making two 4-4-0 locomotives.  The series begins with a discussion "where to start." It's an interesting discussion to me as I am in about the same place he is. This paragraph from the article was especially germane,

"I say this a lot and, I will  repeat it here, draw your model in the scale you will build it. This is especially important in the computer age where many of us do computer drawings. It is tempting to draw what is on the railroad drawing and just scale your drawing. So let 's look at what happens when you do this. Suppose there is 1/4" clearance between some of the valve gear parts and you draw it up that way.  When you scale your drawing to O Scale, you now have around .005" clearance. How good are your machining skills? Can you actually make that stuff? Suppose your prototype has a dimension of 4-3 /4" somewhere on it. If you divide 4.75 by 48 (our scale) you get .0989". Great, where are you going to get material that thick? On my models, the frames ,are 4" thick. That's .083" in O Scale. You can't get sheet brass in that thickness , but you can get .080" thickness, so that is what I used. The other problem is all the parts of your model are related. Now that I changed the frame thickness , how does that effect other parts of the model? I decided the outside dimension of the frame, from side to side, was what I felt was i1nportant, so I made that to the drawing. That decision now affects dimensions of the cylinders, firing deck, pilot beam and valve hangers . As you draw the model, you will be thinking of how things are going to fit together and how you will make then1. l would reconmend that you get the mechanism and boiler designed to fit before you start building. The rest of the parts are not critical to your model running."

 I think he is right on the target with this statement. This is fact of life when building any model. Rarely can we build a model with every dimension true to scale. This applies to structures, rolling stock and even track. The key in a locomotive is that all parts have to interact and function, and not just look nice. 

In the case of a locomotive with equalized suspension, the scale factor is even more out of whack. We (well, most of us) can't build perfectly scaled down versions of 1860's 4-4-0 locomotives with true scale suspensions, as shown in the image at the left. If you want a equalized suspension on your model, there will be components on the model that just don't exists on the prototype, not to mention that our locomotives use electrical motors instead of steam.  Other prototype parts will be too small to make. It's a fine line to walk, but that's part of the challenge, isn't it.


Source: USMRR Aquia Line and other Model Railroad Adventures

Updated: October 16, 2020 — 11:48 am

Year in Review 1861 American Railroad Journal

 I was reading some past issues of the America Railroad Journal during the time period of the civil war on the Linda Hall library online archive. The excerpt below is the American Railroad Journal's  summary of the effects of the first year of the war on railroads and American business is general written at the start of 1862.  I found it very interesting. It mentions the grain rush that northern railroads were experiencing as well as new track building. It is surprisingly optimistic in those dark times. Note some of the text was missing from the original scanned document, so some sentences may have missing words. 

American Railroad Journal.

 New York, Saturday, January 4  1869. 

Railway and Financial Review for 1861. 


The year just closed has been, by far, the most eventful in our history. A disruption of the country has taken place, and whatever may be the future, still continues. Nearly one-half in area, and one-third in population has practically disappear-ed from the circles of business as well as of personal intercourse. Almost complete, non-inter-course exists, and with it a vast change in the mate-rial condition of the country. 

In one point of view, consequently, we cannot display with our usual complacency, the vast material progress of the country during the year that  was just closed. The customary exhibit shows an increase in the mileage of our railroads to have been only 631 miles, against the usual average of over 2,000 miles for several years past. The small extent opened was in the early part of the year. In the Southern States, we presume that there is not a person employed upon new works. In the Northern, but little is doing, the great contest absorbing the whole attention as well as the means of the country. The cessation of the work of construction is of very little consequence, for present, as there is hardly a section of the try that is not now well accommodated by new lines. 

The change in the political condition of country there has been a corresponding one in commerce. Before the outbreak of the rebellion last cotton crop had very fully gone to market, and its value been realized. The threatened political troubles had, in the meantime greatly diminished commercial transactions, so that the importations into the country for the calendar year have been only about one-half the amount of 1860, or say $180,000,000, against $360,000,000. The fortunate circumstance of a large demand for breadstuffs and provisions, occasioned by droughts in Europe, lead to shipments of these on an unprecedented scale, bringing the balance of trade so largely in our favor as to cause an importation in gold to the amount of nearly $60,000,000, within the year, against an export of an equal sum for 1860. For the first time, the exports of domestic produce from the port of New York have largely exceeded the imports of merchandise. Notwithstanding that cotton has disappeared from our exports, these still continue largely in excess of our imports, excluding specie, a really wonderful phenomenon, considering that the value of cotton exported, for several years past has averaged nearly $200,000,000. This fact is striking testimony in favor of the resources of the country, and the capacity of our people of instantly adapting themselves to an altered state of affairs. The causes referred to have averted a great commercial revulsion, for although the Banks have recently suspended specie payment, the step was not caused by any lack of specie, or capital in the country, but to a disturbance in internal exchanges, for the want of a proper system of taxation, to return to the centres of trade the loans made in these on account of the war. 

The year has, on the whole, been a very favorable one for the railroads of the Northern States. Their earnings the present season greatly exceeded those for 1860. Their traffics have immensely increased, to supply the foreign demand for breadstuff's. Their operations have not in a single instance been interfered with on account of the war, which has been carried on exclusively on Southern soil. Whatever may be the result, there is no probability that any Northern State will become the scene of hostilities. It is, consequently, a somewhat remarkable fact, that in a period of civil war, the value of railway properrty should have improved, while that of all other kinds has greatly deteriorated. We see no investment so little liable to be injured by it, as in railroads. The closing of the Southern portion has had a tendency to increase the traffic of great lines reaching inland, which for the wi(??) will show a great increase over 1860. 

While the general retrospect for the past y(??) is not encouraging, and while we do not chose to indulge in speculations as to the future, it is small consolation to point to the great interest which our JOURNAL is devoted, as the one which  remains unaffected, unfavorably, by the war, and whose prospect for the future is most encouraging. The internal commerce of the country has been and remains most active, and the works over which this is carried on, most prosperous. Every year is likely to add to the traffic, showing that investments in them promise for the future to make up in a considerable degree for the losses and annoyances of the past, and to prove a stay and support when everything else is sinking from under us, or yielding greatly diminished returns. 

Source: USMRR Aquia Line and other Model Railroad Adventures

Updated: October 16, 2020 — 2:01 am