A new chassis for an RSD-5

As a modeler of the steam-to-diesel “transition era,” I want my motive power fleet to include models of all the diesel power that operated in my modeling locale. One of these is the Alco RSD-5.

Since I model the area of the California coast south of San Luis Obispo, I rely on my interviews with Malcolm “Mac” Gaddis for information on the operation of those RSD-5 engines in that area (to read that interview, you can see my post at this link: https://modelingthesp.blogspot.com/2011/08/san-luis-obispo-operations-3.html ). Happily, that RSD-5 operation took place in my modeling year of 1953.

Although the RSD-5 was first produced at Alco with all hood doors louvered, as was the case with the preceding four-axle model RS-3, a number of buyers of the RSD-5 ordered the engines with air filtration openings in the long hood. SP was one of these. When the 14 locomotives for Pacific Lines, SP 5294–5307, were delivered in the spring of 1953, they came with the standard Alco exhaust stack, but SP soon replaced these with a large, water-cooled spark-arrester stack. 

The photo above is by F.C. Smith (courtesy Guy Dunscomb) at Bakersfield in February 1954, by which time SP had decided the best use of these units was as Tehachapi helpers. You can clearly see the square filtration openings near the top of the hood on this left side view.

For a view of the right side of these engines, below is a detail from a Stan Kistler photo of SP 5301, descending Tehachapi with the Mountain Local. It’s a better view of the water-cooled spark arrester. The engine here is running in reverse of normal practice with the early RSD-5s, which was long-hood forward. The air filter areas stand out in this view.

 I have long had in my locomotive roster a Stewart/Kato model of an Alco RSD-5 roadswitcher. It always ran very well, back in the DC days. That original body shell had been molded with all louvered doors on the hood. I had sliced off the door louvers and approximated the filter openings, and applied a water-cooled stack from Rob Sarberenyi. I added the full “Tiger Stripe” orange diagonal striping in which the locomotives were delivered. Here’s a view of the model, passing the roundhouse at Shumala on my layout.

But when I set out to add a DCC decoder to this locomotive, I found that something had gone wrong in the motor. It would only operate intermittently and made some unpleasant noises in doing so. I spent some time contemplating repowering the chassis, but was a little worried that there was awfully little room to add a speaker for sound. Then I had the idea, why not simply buy a modern RSD-5 chassis, with DCC and sound installed, and put my shell onto it? I decided to try.

I purchased a new Atlas RSD-5 model, with the intent of replacing the new shell, fully louvered, with my old shell. The new chassis is almost identical in shape to the Stewart/Kato one that I had, so this swap does work. Below is a photo of the new chassis. Its air tanks on each side will have be striped in orange, since you can see in the photos above that these tanks should include the stripes.

I pulled out my old sets of Microscale decals for the SP “Tiger Stripe” schemes (set 87-71), and applied Microscale “Liquid Decal Film” to them to ensure they would apply all right.

The application of the stripe decals is more tedious than difficult, though the end moldings take awhile for Walthers “Solvaset” to snuggle the film down over the contours. The walkway sides are much simpler to decal. Note in the foregoing photos that on these Alco diesels, stripes slanted down toward the rear (short hood) on both sides of the locomotive. I mention this because the pattern was different on SP diesel switchers from some other builders.

An interesting challenge in the lettering is the letter “F” for the forward (long) end of the unit, on each walkway. The standard drawing, as shown in Southern Pacific Painting and Lettering Guide (Locomotives and Passenger Cars), 2nd edition, by Jeff Cauthen and John Signor (SPH&TS, 2019) shows this letter as orange on tiger-stripe switchers. But photographs of Pacific Lines engines in this scheme often show a white or silver gray “F,”  including some delivered in 1952.

Moreover, one shortcoming of the Microscale 87-71 sets I have (possibly corrected by now) is that the decal set only has black letter “F”s. I used a Microscale F-unit set, 87-201,  for the letter “F” which, in current sets, is correctly light gray, not silver. Here is the newly-striped walkway part, installed on the chassis. Couplers and some handrails remain to be re-installed.

I have already verified that this locomotive operates nicely on my layout. It will now take its turn on some local freights in future operating sessions, further illustrating the steam-to-diesel transition underway in my modeling year of 1953.

Tony Thompson