Building the Little Railroad
The North American Live Steamer, Volume 1 Number 11
by Frank H. Moore, Jr.
- (The author has participated in the building of the Paoli, Leopard and Sugartown Railroad of the Pennsylvania Live Steamers from the start of construction, and this article is based on that experience. Nevertheless, the opinions expressed are the author's own, and are not an official pronouncement of the Pennsylvania Live Steamers.)
1. Land
For the small railroad, the nature of the track of land available dictates, to a large extent, the layout of the track. The site available for the Paoli, Lopard and Sugartown borders upon a secondary highway which carries little traffic. From this, the land slopes upward for about 200 feet to a low ridge, then drops off on the other side of the ridge. The alternatives considered were a loop near the road, and a loop farther back from the road. The first made possible a level loop, the side near the road being about two feet above the ground, with the engine terminals on this side. It was fondly imagined that such members of the public as were interested would stand outside the fence and watch firing up. (How naive!) ON the other hand, a level loop could be built around the ridge, with the track above the ground on both side, or a loop could be built on the opposite side of the ridge from the road. The last, however, would have entailed more excavation, and more difficult excavation due to the presence of many glacial boulders, ranging in size up to that of a very large desk. In favor of the back location, all would have been hidden from the road, and perhaps much of the public would not have known of the existence of the railroad.
The plan adopted was the first. On a Sunday afternoon, when engines are operating cars have been parked for the length of the adjacent field, while their drivers paraded over the railroad as though they owned it. Occasionally, some idiot drives past at too great a speed, creating a traffic hazard. The owner of the property, one of our own members, to reduce this danger, has made a part of the adjacent field available for parking by the public.
There is also the possibility that a fence rail may break under the weight of people perched thereon. To alleviate this, we have planted roses along the fence, as barbed wire is verboten along the road.
Another factor which was not properly considered when the line was located is the matter of cutting grass. Before the construction of the railroad, the grass grew long, as in a hayfield, and the cuts and fillers were originally seeded with sweepings from the hayloft. AS time went on, however, it became necessary to mow the grass like a lawn. The vast majority of the tract is taken care of by the forces of our good landlord, but the part abutting upon the track and engine terminals, which cannot be reached by the power mower, must be taken care of by the club. Therefore, the ground around the engine terminal has been covered by broken stone and salted and oiled to prevent the growth of grass. The track has also been oiled for the same reason.
It would be very interesting to have a report of the experiences of other clubs in handling the public, care of the grass, and other matters. The consensus of opinion of the members of the Pennsylvania Live Steamers is that the place for a railroad is back from the road, away from the public, and preferably in a shady place.
2. The Nature of the Layout
A little railroad must be planned for the purpose intended. Personally, I regard the purpose of any railroad, from H00 to 4 foot 8-1/2 inch or even 7 foot 1/4 inch, as to afford a place to operate locomotives. A club railroad should have capacity for the maximum number of locomotives, in proportion to the expenditure of effort for its construction. This dictates a loop, since any layout requiring the throwing of switches, or the reversing of the locomotives, will reduce the possible frequency of trains, and number of locomotives which can be operated simultaneously.
Further, I think that one of the most interesting functions of a railroad is the testing of locomotives. This can be most satisfactorily done on a loop. It is worthless to read that Joe Doe's engine pulled five people up the grade of the Madagascar Live Steamers line; how do you compare it with yours? Does everybody have to build a grade of this percentage? Yes, I know that you can multiply the weight by the percent grade to get the grade resistance, but it still is not as good, especially in dealing with locomotives of vastly different sizes, as a level test. Further, on any line other than a loop you cannot have a continuous test. In Germany, the big locomotives are tested by placing a dead locomotive behind the dynamometer car to compress air, and in England a similar effect is obtained with an electric loading car, but who wants to do this with our little fellows?
A level line also permits the operation of smaller locomotives and the pulling of more load by the big ones. The initial loop of the Paoli, Leopard and Sugartown is, therefore, level, and is the ideal arragement.
3. Arragmentment of Gauges
When the Paoli, Leopard and Sugartown was first planned, there were locomotives available for immediate operation in 2-1/2 inch and 3-1/2 inch gauges. Before construction began, several members indicated an interest in 4-3/4 inch gauge, and it was decided to incorporate these three gauges. To get the possibility of operating the most locomotives for a given expenditure of effort, and as quickly as possible, all of these gauges were placed in a single track. We were using second hand ties from a 7-1/2 inch gauge railroad, so it was decided to lay the three gauges side by side, not one within the other, as this gave a better scale appearance in proportion to the ties. This had two great disadvantages. First, the two inside rails of the four are common to two gauges, and the inside of the three gauges cannot be gauged without disturbing one of the other gauges. Secondly, these two rails are traversed by flanges on both sides, which means that frogs must be special. ON the other hand, an advantage is that on no gauge do the rods or injector overflows come over the rail of another gauge to drip oil or water on it.
On the Paoli, Leopard and Sugartown, there are two engine terminals. One, inside the loop, serves only the 2-1/2 inch and 3-17/32 inch gauges; the other, outside the lop, serves only the 4-3/4 inch gauge. AS the 4-3/4 inch track is on the outside of the loop on the main, its sidings leave the main loop by conventional frogs and split switches. The sidings to the 2-1/2 inch and 3-17/32 inch engine terminal leave the main by stub switches and special frogs.
The arrangement of gauges, on a multiple gauge railroad, should have only one common rail, and all gauges should be set off from it. If two engine terminals are provided, one on each side of the main, the gauges on the main should be placed on both sides of the common rail, in such a way that each gauge is restricted to that side of the common rail on which is its own engine terminal. This makes it unnecessary for the common rail to be crossed by any other rail, and all frogs will be conventional.
4. Engineering
For a railroad of the size of the Paoli, Loepard and Sugartown, the easiest way to lay out a tangent is to stretch a string between two stakes, and the easiest way to lay out a curve is to swing an arch of a circle, using a steel tape or wire as a compass. When this is done, the tension on the tape or wire must be kept as constant as possible, to avoid stretching, and the tape must be kept horizontal, to avoid shortening the radius.
Where a building or other obstruction prevents swinging an arc with a compass, the methods used in layout of the big railroads are handy. I recommend a study of "Field and Office Tables", and the accompanying text "Railroad Curves and Earthwork" by C. Frank Allen. Briefly, on the big railroads, the sharpness of a curve is measured by the degree. The degree of a curve is defined as the angle at the center subtended by a chord 100 feet long. (See Figure 1) This practice is arranged to make things as easy as possible. All you have to do is to set up the transit at the point of curvature (PC), and lay off successive angles of 1/2D, D 1-1/2D, 2D, 2-1/2D, etc. At the same time, the chainmen cut these angles with the successive 100 fort chords. These curves are too large for the Paoli, Loepard and Sugartown, so we scaled one down, and used the same procedure with ten foot chords, on the hill track where the club house intervened.
A curve must be superelevated, and, if an arc of a circle meets the tangent, the outside rail should theoretically suddenly jump up a distance of as much as six or eight inches, on the big railroads. To avoid this, the foreman, O'Sullivan, may pull in the track toward the center, at the point of curvature, as in Figure 2. The curve then begins at B instead of at PC, and a gradual transition from tangent to curve is obtained. Sometimes this freehand, or O'Sullivan' spiral, is smoothed by having a locomotive run over it a few times before the ballast is placed between or at the ends of the ties. It will be seen, however, that if this kind of transition is used, there will be a point C, along the curve, where curve will be sharper than would be the case if no transition were used.
A better way to obtain a transition is to pull the whole curve in the direction of the center, as in Figure 3. Here again, big railroad practice is adapted to make things easy for the layout in the field. The AAR spiral approximates the cubic spiral. (x equals ks3) and may be laid out by means of a transit set up at the beginning of the spiral and a pair of chainmen, who lay off ten points on the spiral by equal chords. Since the engineers of the Paoli, Lopard and Sugartown did not always have a transit handy, the spirals were laid out by offsets from tangent, using the easy tables in Allen's book, and scaling down to suit our purposes. These curves are not used universally by the big railroads, so do not be surprised if somebody tells you that the XYZ does use them. They are used by all. The four transitions of the PL&S were laid out in the manner described, but as this was about eight years ago, I do not know how closely they approximate them now.
Another curve which is very handy is the parabola, (y equals kx2). If you cannot swing an arc of a circle, this is the easiest curve of all to calculate and lay out, without tables. It can be used for alignments, but is handiest for vertical curves, where to grades meet at the top of a hill or the bottom of a sag.
I have been told that the HO railroad in the Wilmington, Delaware, Pennsylvania station laid out transition curves by unwinding a string from around a wastebasket. This gives an involute curve. Personally, I cannot see where it would be particularly useful for railroads such as ours. It is the curve used for almost all gear teeth, and, if anybody wants to investigate it, see "Spur Gears", by Earle Bucking ham, Chapter III. This gives a good discussion of the curve, including a table of the involute function, which is defined as the tangent of an angle minus the angle itself (expressed in radians).
5. General Construction
The Pennsylvania Live Steamers originally considered various types of construction of the railroad. Personally, I belonged to the faction which favored building an elevated structure, as I believed that riding would be easier if the legs could hang down, as in riding a horse. I am very happy to report, however, that it was decided to build the line on the ground, using the same methods of track construction which are used by the nearest neighboring outdoor railroads, the Pennsylvania, Reading, and Philadelphia and Western. This avoided buying lumber for a structure at a time when wood was scarce and expensive, avoided complications at turnouts, gives a very fine roadbed which can easily be surfaced and leveled, and gives a fine scale appearance. As to riding on the ground, I am so convinced of the ease of riding a 2-1/2 inch gauge flat car that I am planning to build a rider car for my son's 2-1/8 inch (STandard) gauge railroad. For anybody building a live steam railroad I unhesitatingly recommend the construction which the big railroads have found most successful.
6. Grading