More distinctive flat car loads

I have always enjoyed making and operating flat cars with distinctive loads, and am always on the lookout for additional opportunities to make them. Almost always, I make them removable, so that loads delivered on my layout can be picked up as empties in a following session. This post begins a series about two more loads, in these cases fairly distinctive ones. 

The first one I’ll describe is a load I’ve owned for some time, a marine boiler. I’m not sure of the source (a reader may know), but it sticks in my mind that it was from Chooch. Anyway, its width will fit on an HO-scale flat car, with the boiler’s long axis parallel to the length of the car, and that is one way to mount it. I prefer removable loads, and this one will be that way too.

I did wonder about what kind of marine boiler this might be, and my friend Ben Hom (a shipboard engineer during his time in the Navy), directed me to some excellent resources. First, the Wikipedia entry for Scotch marine boilers, as this type was known: https://en.wikipedia.org/wiki/Scotch_marine_boiler . 

In the above model view, the closed opening at the bottom is where fuel enters the combustion chamber, the middle section above that is a fire-tube boiler, and the steam is collected in the top part with the heavier bolts. The inside of this is shown in the side-view cross-section below, from the Royal Navy’s Stoker’s Manual of 1912, which can be found on the Wikimedia page for Scotch boilers. Path of hot gasses is shown by red arrows, movement of water in the water space is in black arrows.

In looking at the numerous photos of loads of this general kind, I always recall a group of Southern Pacific photos taken when their home-built Class F-70-4 depressed-center cars were new. It was during the run-up to World War II, and the photos show marine boilers being delivered on these cars to the shipyard in Richmond, California for use in Liberty ships. Here’s one of them, with the SP car in the foreground; note the light color of the boilers:

For more about the Liberty ships and their boilers and steam engines, I would recommend a really interesting and complete report on the topic (see it at: https://ww2.eagle.org/content/dam/eagle/publications/company-information/workhorse-of-the-fleet-2019.pdf ).

A close-up of the boiler still loaded on the car is also illustrative, because you can see the tie-down method (it looks like cable, but could be steel strapping). Note that the drum-shaped boiler is a bit wider than the car. Incidentally, SP’s notes on the photo state that this boiler weighed 52 tons, so a flat car of 70-ton or more capacity would be needed. Here again, the three combustion chambers are at the bottom, the fire tubes are in the middle, and the steam section is at the top.

Since I had a second model boiler like the one shown at the top of this post, I cut it down so that it could be mounted “cross-wise” like you see on the SP car shown above. It’s shown below after painting, a light color like the boilers shown in the SP photos. This is the “back” of the boiler, compared to the photo above.

I was interested to know more about how this boiler worked, so I did spend some time with a serious book on the topic (Steam: Its Generation and Use, 38th edition, published by Babcock & Wilcox, New York, 1972), but didn’t find much help. Evidently the Scotch marine boiler was not of great interest to Babcock & Wilcox.

I have been exploring simple bracing for securing the boiler. The SP photo above, showing the load on the car, seems to have really minimal bracing, and tie-downs over the top of the boiler, so I will do the same. I’ll continue with that part of the topic in a future post.

Tony Thompson