This is a general topic, and of course can range from the earliest days of the Central Pacific, up the very late days of the Southern Pacific itself, prior to the Union Pacific takeover in 1996. Each period of 20 years or so naturally has a different car fleet to consider. I’m just going to talk about the time from post-World War I, up to the end of the 1950s in this post. I will only summarize the history; there is a quite extensive and detailed book on this topic, Volume 2 in my series Southern Pacific Freight Cars (Signature Press, 2002).
I will begin with SP’s largest class, by far, of cabooses, the Class C-30-1. In the latter part of World War I, SP began construction of the C-30-1 cabooses. These were quite similar to the preceding Harriman Class CA cars, but with a full steel underframe. (The CA cars had had oak center sills from bolster to bolster, though steel draft gear was applied.) Toward the end of the preceding Class CA construction period, a “narrow” cupola was introduced, with walkways along each side of the cupola. This cupola was continued with Class C-30-1. It’s shown below. Note slant sides, railing around entire roof circumference, and walkways alongside.
The photo above is a classic view of a C-30-1 car, taken at Bakersfield on September 18, 1948, by Richard W. Biermann (Arnold Menke collection). This car was built in 1926 and re-uses the number of a much older car. It still has its original narrow cupola. The paint and lettering are up to date for the 1948 photo date: spelled-out road name, and white side handrails.
After building about 300 new cars of this class, numbered up to 899, SP began to re-use the lower numbers of retired cars, and that is the case in the photo above. Awhile back, I supplied a partial history of the SP Class C-30-1 cars, those that had the re-used, lower car numbers. That post is here: https://modelingthesp.blogspot.com/2012/08/my-renumbered-sp-wood-caboose.html . Eventually SP built over 620 cabooses to this design, far more than any other SP caboose class.
Modelers will know that Walthers produced an accurate and quite nice plastic model of the Class C-30-1 cars, complete with narrow cupola of the original configuration. Here’s a photo. Like the prototype photo above, the model shows post-1946 lettering and white handrails.
Up until the late
1940s, most of these cars had black roofs, which was actually car cement
(mopped on with a string mop!), over the canvas covering of the wood roof. But from then on, SP painted the roofs body color, as they had done on all-steel cupola cars from their inception. That’s why the model above has a roof of body color.
Starting in the last year of Class C-30-1 construction, 1927, SP returned to the full-width cupola it has used on the early Class CA cars, in the first decade of the 20th century. It was still slant-sided and of course had no side walkways. That same cupola was applied to following classes C-30-2 and C-30-3, and to any older cars needing replacement cupolas — which is why cupola configuration alone is not a spotting feature for SP cupola cabooses.
Still later, after 1937 when the first steel cupola cabooses were built, SP designed a new, steel replacement cupola for older cars. It had straight sides, and over the following 20 years was applied to many older cabooses. Shown below is a Balboa brass caboose, which many modelers relied on before the advent of the Walthers model, and the very nice Precision Scale brass cars.
You may note that this model has a replacement cupola, corner handrails only on the roof, and a center roof walkway, changes that began in the late 1940s on some cars.
The Class C-30-1 caboose is an essential part of any SP modeler’s fleet in the transition era, and even into the 1960s. Its huge numerical dominance meant that it was by far the most common caboose, even though in later years the steel cupola cars and the new bay-window cars began to be used on mainline trains. But I will discuss those cars in future posts.