Advanced Steam Loco Development

Advanced Steam Locomotive Development – Three Technical Papers

Porta L.D., Advanced Steam Locomotive Development – Three Technical Papers, published by Camden Miniature Steam, 2006, ISBN978-0-9547131-5-7. A4-size, 100 pages.

The book is rare if not unique in publishing papers by the great Argentinean steam locomotive engineer Livio Dante Porta (1922 – 2003) who took over the mantle of steam development from Chapelon in the mid-1950s, but whose work has remained largely unpublished and unknown.

The book is divided into four chapters:

  1. Livio Dante Porta: A brief biography;
  2. Steam Locomotive Developments in Argentina, Porta’s famous “Manchester Paper” as presented to the Institution of Mechanical Engineers in Manchester in 1969;
  3. Fundamentals of the Porta Compound System for Steam Locomotives: first circulated privately in 2000.
  4. Some Steam Leakage Tests on Locomotive NORA of the Ferrocarril Austral Fuegino (FCAF), Oct 1999.

The most important amongst these papers, taking up 36 of the book’s 100 pages, is his “Fundamentals of the Porta Compound System for Steam Locomotives“.  In fact, this paper might have been more accurately named “Fundamentals of Steam Locomotive Cylinders and their applicaton to the Porta System of Compounding” since it covers a far wider range of topics than compounding. Indeed, the first half of the paper covers general aspects such as steam leakage, wall effects (condensation), triangular losses and heat insulation, all of which are of the greatest importance in their application to simple expansion locomotives. This paper is not an easy read, made harder by typographical errors, but it is well worthy of study and should be essential reading for all students of “modern steam”.

The fourth paper on steam leakage tests on the FCAF is only three pages long (excluding appendices), but provides useful information on the measurement of this important and oft-neglected phenomenon.  The subject of steam leakage itself (as referring to leakage past valve and piston rings that can easily exceed 10% of steam consumption) is described in more detail in the preceding “compounding” paper.

The book is highly recommended to anyone with an interest in the theories and technology upon which “modern steam” is founded.



Several pages of this website include text and diagrams copied from Porta’s “compounding” paper, including the pages covering condensation/wall effects, steam leakage, clearance volume, incomplete expansion and triangular losses.  More specific references to his theories on compound expansion can be found on the α Coefficient and Compound Expansion pages.

Sincere thanks to Adam Harris of Camden Miniature Steam, publishers of “Advanced Steam Locomotive Development – Three Technical Papers” for allowing the sections of the book to be published on this website.