Book Review: Camels and Cadillacs - A History of the South African Railways 25 Class Condensers and 25NC 4-8-4's

This 1981 image by Malcolm Best shows Condensing 25 Class locomotive 3411 taking on water at Hartswater, SA.

This 1981 image by Malcolm Best shows Condensing 25 Class locomotive 3411 taking on water at Hartswater, SA.

Author Phil Girdlestone
Stenvalls Publishing - 2014
ISBN: 978-91-7266-185-1

Renowned steam locomotive mechanical engineer Phil Girdlestone, a contemporary of David Wardale, Nigel Day and Shaun McMahon, has written an outstanding history of the most advanced locomotives to operate over the 3'6" gauge South African Railways (SAR). The twin-class of 4-8-4 steam locomotives were unique in the rail industry worldwide – the Class 25 condensing locomotives, nicknamed "Camels" by crewmembers due to their prodigious water range, were the most successful condensing steam locomotives ever produced. Identical in nearly every measure except condensing equipment were the 25 NC ("non-condensing") locomotives, likewise nicknamed "Cadillacs" due to their exceptional ride quality.

Girdlestone provides a technical perspective on the locomotive classes only an engineer familiar with steam locomotive design, and these classes in particular, could account. The book is structured chronologically, beginning with a detailed history of 20th Century SAR locomotive development, up until the procurement, design, and production of the 4-8-4 locomotives. The construction of the classes, which took place between 1952 and 1955, included the provision of a total of 90 Class 25 Condensing and 50 Class 25NC locomotives.

The detailed look provided by Girdlestone outlines both the strengths and weaknesses of these classes of locomotives. The locomotives were unique in that they incorporated the most advanced of mechanical improvements available at the time, a melding of European locomotive design and manufacture (in the UK and Germany) and important U.S. components. A one-piece cast frame, cast water bottom tender, tender trucks and roller bearing side rods were furnished by U.S. firms General Steel Castings and Timken (side rods). Germany's Henschel manufactured the majority of the 25 NC locomotives and North British Locomotive Company produced all but one of the condensers.

For the inquisitive student of steam locomotive history, this pragmatic view of their development points out areas of improvement, details the struggles of getting locomotives commissioned and associated "trouble shooting," and outlines the nuances of condensing appurtenances and roller bearing side rods. High quality technical illustrations augment the text. The performance of both condensing and free exhausting locomotives is also compared.

Of specific interest to CSR is the penultimate chapter of the book, preceding a phenomenal color image gallery outlining the class, which discusses in brief detail the developments associated with 25 NC 3450, otherwise known as the "Red Devil."

The following quote stands out to the reviewer:

...the trials were undertaken on freight trains over the 70-mile-long electrified line to Witbank, which with its 1 in 50 [2%] ruling gradients in both directions was a severe testing ground.... By November 1981 it was considered that the tuning up had reached a point where comparative dynamometer car tests could be carried out between No. 3450 ["Red Devil"] and a standard 25NC No. 3438.... These tests were carried out mostly in the upper part of the locomotives respective power ranges and under these conditions No. 3450 gave very high coal and water savings. Up to 60% coal savings per drawbar hp was achieved compared with No. 3428, equating to a 150% increase in drawbar thermal efficiency, and additionally No. 3450 was capable of developing significantly higher power.

While under less strenuous passenger service savings were slightly lower, it was evident to SAR staff that the 25 NC and, specifically, the Red Devil, were the most economic locomotives operating on the railroad. A railroad Traction Committee was tasked: "to consider the relative costs of steam, diesel and electric traction... [found] that steam locomotives, particularly No. 3450, were the cheapest form of traction to operate between Kimberly and De Aar and, by implication, on other sections as well."

In an era when the majority of steam-related books often belong on coffee tables, it is nice to see something with a similar level of "meat" as The Red Devil and Other Tales from the Age of Steam.

More information about the book can be found on the Camden Miniature Steam Services Site.