Arthur Mellen Wellington's Railway Location

A. M. Wellington was a railway civil engineer, perhaps the most celebrated of his time. His fame rested on a book called "The Economic Theory of the Location of Railways," which was published by John Wiley and Sons in 1887. By 1906, the sixth edition had appeared, and "Wellington" was required reading. The book was subtitled "an analysis of the conditions controlling the laying out of railways to effect the most judicious use of capital," which states its fundamental theme. The large volume contains very much else of interest in the pursuit of this end. Whether read as history, for the facts contained, or for its still cogent engineering analysis, the book is indeed a very good read.

Wellington is regarded as the father of the subject of engineering economy, which is the analysis of the economic consequences of engineering decisions. The importance of this study is evidenced by its inclusion in the Fundamentals of Engineering examination on the path to the certification of an engineer. It rests mainly on the reduction of the consequences to monetary amounts and the comparison of amounts at different times on the basis of compound interest.

Wellington located the American-financed line from Vera Cruz to Mexico City via Jalapa. This line climbed onto the Mexican plateau with a maximum grade of 2 per cent, compared to the 4 per cent of the earlier Mexicano railway to the south via Orizaba, in roughly the same distance. A description of this location is given in an Appendix. Also mentioned are the High Line of the DSP&P from Denver to Leadville, and the UPD&G from Georgetown to Silver Plume, where one can still ride today, among many other illustrated examples.

A fascinating curiosity is Wellington's enthusiasm for switchbacks in overcoming difficult problems. He suggests that the Silver Plume line could better have been built a little to the north, where the interstate now is, using switchbacks, but mentions the tourist attraction of the loop and bridge. We are fortunate that the loop was built, since otherwise both the line and Silver Plume would have been wiped out by the highway, instead of just Silver Plume. Wellington proposed a series of switchbacks with the tail tracks raised so that cars would come to a stop and automatically reverse, oscillating back and forth through spring switches from top to bottom without the need for any other motive power than gravity. He had a solution for the problem of brake failure, so the scheme was eminently practical, though never used.

Wellington defined Engineering as the science "of doing for a dollar what any fool can do with two, in a fashion." Whether he invented them or not, he established the use of percent grade instead of feet per mile, degree of curvature instead of radius, and the cubic parabola as a transition spiral, all of which became standard American practice. He made measurements of train resistance, beginning when he was referee at the Burlington brake trials in 1886, which were some of the first reliable measurements made in the United States on this important subject. He analyzes curve resistance in detail, in which he was a pioneer. There is a large section on the locomotive and its work. In spite of containing much real engineering of this kind, the book is nonmathematical by design. Wellington says that the mathematics is widely available in other works. The book is, therefore, of use to the nonengineer, to the manager as well, and Wellington distinguishes the material appropriate to the different classes of readers.

He thoroughly appreciated the outstanding importance of rail stiffness, and made it very clear why the use of light rail was a false economy. He pointed out that one was not buying steel, but "stiffness, strength, and durability," and that when rail was priced on the basis of stiffness, the superiority of heavy rail was evident. This principle is as valid today as it was when Wellington demonstrated it. He shows that narrow gauge had no economic advantages, in fact much the reverse, and that standard gauge was practical with the same grades and curvature. The fact was becoming apparent at the time, he notes.

The book is dedicated: "To the great men of a former generation, who orginated the American railway system, this attempt to improve on their practice is admiringly inscribed, in token of respect for their far-sighted sagacity and still unequaled skill." Among these men, he mentions Latrobe (Baltimore and Ohio), Jervis (Mohawk and Hudson, and many more, including the Rock Island), Thomson (Pennsylvania Railroad), and Whistler (Western RR of Mass, and many more). Any student of railway engineering history who is acquainted with the accomplishments of these men will second the praise. After these men, the art of railway location practiced in the midwest did indeed fall to a low standard, of which Wellington provides many examples.

Wellington also said that it was not just the question of how to do something, but of whether to do it at all. He made it clear that the cost of any improvement must be measured against the possible returns, and the important thing was to compare alternatives, not simply to consider a single problem in isolation. These principles have become the basis of engineering economics, it will be noted.

Most route engineering books consider curves and grades as major topics, in fact the central topics of their presentation. Wellington, to bring out a very important point, calls them "Minor Details of Alignment" to shock the traditional engineer. He then points out that he calls them minor because there are the greater questions of route and ruling gradient to be decided before they are considered, and no excellence in the details can ever overcome poor choices in the greater matters. In modern terms, this is recognized as one of the benefits of "top-down" design. The false economies of long tangents, or of expense to limit rise and fall, or of building light bridges, are analyzed and clearly demonstrated.

The engineering student, practicing engineer, engineering historian, or railway enthusiast will all find much of interest and value in Wellington, and will come to know what a real engineer is like, and how he thinks. The age of this book does not detract from its importance: it is a classic.

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Composed by J. B. Calvert
Created 22 May 1999
Last revised 29 January 2005