Monday, September 20, 2021

SP steam locomotive paint details

 I receive from time to time, questions about details of how Southern Pacific steam locomotives were painted and lettered. I always begin my response by recommending the book on this topic from the SP Historical and Technical Society, Southern Pacific Painting and Lettering Guide (subtitled “Locomotives and Passenger Cars”), by Jeff Cauthen and John Signor, now in an expanded and revised Second Edition (SPH&TS, Upland, CA, 2019). It’s authoritative and complete. My advice? Buy the book.

But there are still points to be made, beyond what is contained in a necessarily very broad-brush book. For example, SP steam, especially smaller engines, often had red-trimmed cab windows. This was at the discretion of local shops, and certainly it’s known that some shops didn’t do this. It’s also known that the shade of red that was applied varied from shop to shop — and likely from time to time.

But when this was done, it can be quite dramatic. Shown below is a George McCarron photo at San Luis Obispo in 1954 (John Signor collection), which makes the point vividly. The locomotive is Class C-9 Consolidation 2581, assigned at San Luis for a number of years. It mostly worked in yard service, as can be concluded from the pilot footboards. You can click to enlarge.

Note also here that the graphite smokebox is quite evident, and that most of the paint is quite glossy and fresh. Note also something seen on some engines in later days, the very rusty stack. And don’t forget how rusty the coupler looks.

The issue also arises about painting the boiler check valve and injector red. This was, again, not universal but was a shop choice, and was most common on smaller power. Color photos, when they can be found, often show that the check valve color faded, probably due to heat, while the injectors often remained a brighter red. I will show a couple of examples, Dallas Gilbertson photos, courtesy of the late Tom Dill.

First, a nice example of the fading of the check valve, relative to the injector next to the cab. This is one of SP’s Sacramento-built 0-8-0 switchers, with boilers from dismantled Atlantic engines. Erected in 1930, they were assigned to Class SE-4. They operated with a wide variety of tenders. The locomotive is shown at Los Angeles in May, 1954, in a detail of the full slide.

At the other extreme, occasionally these paint details can be seen on larger power. Shown below is cab-forward 4274 on the Taylor roundhouse turntable in December 1953, in another Gilbertson photo.  This was the last engine of Class AC-11. Note the unlettered tender and that cab windows are not visibly red. Again, this is a detail of a larger photo.

Since these details do not show up on every SP steam locomotive, I advocate that they be applied sparingly in one’s fleet. On my own small SP steam, I have used a slightly redder color on the injector than on the check valve, as shown on the smaller locomotives above. Here are two of my 2-8-0 engines, shown in my layout town of Shumala’s engine terminal.

Note here that you don’t see red cab windows on either of these models. Brass SP Consolidations are often modeled with the sliding side windows out of sight. On models which include the windows, however, I have added red frames to a couple of engines. This is in keeping with my observations of prototype photos. Shown below is Mikado 3251, Class Mk-6, a Hallmark model re-detailed for Pacific Lines by Al Massi.

Like any topic, the only way to decide how to model something like steam locomotive painting details is to carefully examine prototype information. The challenge with a topic like that of today’s post is that color photographs are very much a minority of the available images. I’ve tried here to convey what I believe is appropriate.

Tony Thompson


  1. Hello Tony,

    Thank you for your article regarding RED painted check valve & injector.
    Kindly let me know the reason of the red painting on them.

    Thank you.

    Ryoichi Fukushima
    Yokohama, Japan

  2. The standard story is that these were parts that were hot when the locomotive was under steam, thus the red served as a warning. This has always seemed a little overly simple to me, but the red paint is a fact, whatever the reason.
    Tony Thompson