Friday, October 21, 2022

Power balancing

 By “power balancing.” I refer to movements of motive power across one division to another, or even from division point to division point within a division, to bring motive power assignments into balance. This is a more likely occurrence with big power than with small power, and there are plenty of prototype photos of big power operating “light,” that is, without a string of cars. 

(We keep in mind, of course, the definition of a “train,” from the book of rules: “An engine, or more than one engine coupled, with or without cars, displaying markers.” So contrary to what modelers sometimes think, the presence of a caboose has nothing to with making it a train — though of course, a caboose is handy for displaying markers.)

The most common reason for light movement of engines is helpers returning from an assignment, thus commonly seen on mountain grades. Below is a Southern Pacific example I’ve always liked, a Wilbur C. Whittaker photo near Yuba Pass on the west side of the Donner grade, in the summer of 1950: a pair of cab-forwards coupled together, making a train.

But there are lots of other examples. In my interviews with Malcolm “Mac” Gaddis, who worked at San Luis Obispo in the early 1950s, he mentioned that on the Coast Division, power balancing often involved 2-10-2 locomotives, and he even described a 2-10-2 cab ride he made during such a move, from Santa Barbara back to San Luis. (To see that account, use this link: ).

Here is an example of such a move, photographed by John Shaw on a rainy New Year’s Day, 1956,  2-10-2 no. 3672 turning on the Watsonville Junction wye to return light to San Luis, where it was assigned for years. Note the slicker-clad brakeman on the rear tender step, and the snazzy two-tone pickup truck. (You can click on the image to enlarge it if you wish.)

One of the comments by Mac Gaddis that I enjoyed was this one: “I’ve always been on good terms with dispatchers, and I would call up and ask ’em, with some locomotive move like three light engines moving, ‘what’s going on?’ They would say, ‘Oh, we’re balancing power,’ and I’d say, ‘That covers anything, doesn’t it?’ ”  For more on that part of the interview, see: .

This is tempting to reproduce in model form. I’ve written about this possibility and others, under the title “Big locomotives on small layouts,” which you can find at: . In that post, I showed both “cab hop” (meaning engine and caboose) and dynamometer car trains. Both are perfectly credible and well-documented on the SP prototype. But light engines can also be modeled in operation.

 Below I show my Broadway Limited Class AC-4 cab-forward no. 4107, running westward light, just passing milepost 270 on my Coast Line layout.

And I like the idea of two or more light engines running together, as Mac Gaddis mentioned. For example, I can run two of my Class C-9 Consolidations, nos. 2763 and 2752, on such an eastward move, probably to Santa Barbara. (No. 2763 is a Balboa brass model, 2752 a Key engine.) In this view, they are passing the Shumala engine terminal.

Including light engine moves is an interesting extension of mainline activity on my layout. Though I only have space to model a short segment of the Coast main line, I like to have range of options for each operating session.

Tony Thompson

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