This is the third post in this series about the full-width diaphragms that were adopted by a number of railroads including Southern Pacific, for new cars in the early days of streamlined lightweight passenger trains. In the first post, I described and illustrated the prototype, with several photos to illustrate the features of these interesting appliances. You can see that post here: https://modelingthesp.blogspot.com/2021/07/the-challenge-of-full-width-diaphragms.html .
In the second post, I made a few observations about commercial products that can represent the full-width prototype diaphragm, either in flexible, working form or in a rigid plastic form that does capture the appearance, though not all aspects of the operation. Here is a link to that second post: https://modelingthesp.blogspot.com/2021/08/full-width-diaphragms-part-2.html .
Now I want to turn to face plates for these diaphragms, particularly the distinctive shape of many of the ones used by SP. These have sometimes been called “opera window” plates because of the peekaboo openings at the top (possibly to save weight). Below is a repeat from the first post, a clear photo of such a face plate on a 1947-built SP car.
One way to make model versions of these plates is simply to cut them from styrene,
after making a pattern. I made patterns by taking a photo like the one above, increasing the contrast using Photoshop, and then sizing the height of
the plate in the photo to 9.5 feet in HO scale (about 1-5/16 inch). Here’s the relevant part of the photo above.
Next I printed out this image on ordinary paper, cut it out with a hobby knife, and then transferred the outline with a pencil to 0.010-inch styrene sheet. Shown below are a paper pattern, cut from the printed-out photo above, and a “first-cut” styrene piece, obviously needing refinement, but I want to show it at this stage to show you don’t have to get it perfect at the start.
The starting blank at right has too high a curvature at the top, and the upper holes are too small and poorly shaped. But with the thin styrene sheet, these defects are quickly corrected with small round and flat files.
Shown below is the same “blank” shown above, but refined in shape and primed with a medium gray color, prior to preparing for use on a model car. This still needs rust tones added.
This will be attached with canopy glue to a full-width diaphragm, or to a residual “narrow” remnant diaphragm. By the latter, I mean what remained after the removal of the full-width part of the diaphragm. The photo below shows such a diaphragm and face plate, on a single-unit diner, SP 10200 in 1956 (Doug Richter photo). You can click on the image to enlarge it if you wish.
I have made a number of these “opera window” face plates, for use on full-width or remnant diaphragms for appropriate cars. I will go into their application in a future post.