Hi guys, lately I’ve really been looking into the technical side of steam locomotives, and I’m finding myself somewhat wanting when it comes to this information.
In particular, I’m looking for in-depth optimal ratios and equations when it comes to Steam locomotive operations, particularly when it comes to boilers and cylinders (such as proportions of superheating to standard tubes) , but really any technical info on any part of locomotives is highly welcome. Really I’d like to know what equations are the most importantly for constructing the optimal steam locomotive (taking into account variables for different running different types of trains of course)
if anyone knows where to look (websites, archives, pdfs etc) or what to purchase for this kind of information, I’d gladly appreciate it.
The definitive reference for designing a steam locomotive will be Wardale’s Fundamental Design Calculations (FDCs). These were available from the 5AT organization, and might still be available from the consultancy it has become.
The reference I used when I first took an interest in steam design was Ralph Johnson’s book (use the 1944 revision) – this may actually still be in print; my copy was bought from Simmons-Boardman with a printing date of 1983.
There are a number of good technical discussions on proportioning. Lawford Fry had a very good understanding of boiler design, but many of his formulae include empirical factors scaled to boiler proportions circa 1922, and won’t give correct numbers for ‘golden age’ or later large steam.
You’ll get nothing but garbage and frustration if you try searching on 'Ralph Johnson".
They have two editions, 1944 and ‘1945’ (a reprint of 1944) with the author’s name “Ralph P. Johnson” (his middle name was Paine). The link to the 1945 edition is