An SP steam switcher, Part 2

A few weeks ago, I posted a commentary on Southern Pacific steam switchers, focusing (as did SP) on the 0-6-0 wheel arrangement. I concluded that a 1950s SP modeler would likely want to model the later switchers with piston valves, and might well choose Class S-12, a large class of 38 locomotives built in SP shops during 1918–1923. That post is located at: https://modelingthesp.blogspot.com/2025/02/southern-pacific-steam-switchers.html .

 This consideration was inspired by an acquisition, a couple of years ago, of a rather ancient brass model, imported by M.B. Austin, of an HO scale SP 0-6-0. I know from the late John Glaab’s Brown Book (3rd Ed.) that this was a run of 400 models, built by KTM in Japan and brought to the U.S. in 1960.

Whether to modify and/or upgrade it, and what to do about its elderly worm-and-gear drive and open-frame motor, were challenges. But I had been attracted to it because of its distinctive tender, one of SP’s 70-C class cars with cut-down oil bunkers for visibility, as I showed in the post linked in the paragraph above. Here’s the model as it came to me:

This view of the right side of the model shows that it has the forward window on the cab side still open, though many S-12 switchers had these forward windows plated over by the late days of steam. To illustrate a plated-over window area on a Class S-12 engine, below is a Stan Kistler photo of SP 1254, taken at Oakland in April of 1953. Note the cross-compound air compressor on this left side of the engine, and the 70-C tender.

But a few engines continued to have windows in this location, including SP 1284, seen below in a Paul Jansen photo of the right side (Clark Bauer collection), working at Bayshore Yard on Coast Division. It too has a 70-C tender at the time of the photo, of a slightly different design. As I mentioned in that previous post on this topic, only the oil bunker was cut down, so the class definition of these tenders, their 7000-gallon water compartments, was unchanged.

Note in both these photos that the smokebox sides are slightly gray relative to the boiler jacket. Applied as a graphite compound, these areas darkened in service from their initial medium gray color.

Before leaving the topic of the prototype switchers, I should mention that tenders were not permanently assigned to engines, but were swapped as needed at major shoppings. Often tender work would be completed before its former engine, and some other engine ready for release would receive that tender. 

My friend Mark Schutzer consented to take on the task of modernizing the drive of this model locomotive, replacing the gear box and adding a can motor (for those interested, Mark’s website, including links to his clinics about re-powering brass locomotives, is at: https://markschutzer.com/ ). 

The original open-frame motor was rather small and as was customary in early days, directly driving its worm on the main axle gear. 

Mark’s first task, after disassembly of the mechanism, was to fit a Northwest Short Line 28-1 gear box to the frame, and add a NWSL universal coupling and a brass mount for the new motor.

With that working all right. a torque arm between gear box and motor was added, and the mechanism reassembled for test.  (both photos, Mark Schutzer)

With this much completed on the mechanism, the next steps were a better locomotive weight, and of course a decoder and sound. I’ll turn to those aspects in a future post.

Tony Thompson