This concerns an admittedly minute detail of the system, yet I'd still like to model it in HO. It's the control rod for the variable release valve on the air reservoir. Although the length varied depending on individual installation requirements dictated by the car design, I would think the diameter would probably have been the same in most cases. I haven't found a diagram that shows it in the car builders dictionaries or Westinhouse Co. pubs.
Anybody know what the diameter is or what pub(s) might show it? Looking at photos of cars where I can see the rod, I'm guessing it's maybe 3/8 in. to 1/2 in.
I've added that release rod on only a very small number of freight cars, and used .008" phosphor-bronze wire from Tichy. In HO scale, that's roughly 3/8" diameter.
(While most viewers here know that clicking on the pictures will yield a larger picture, I'm mentioning it here for those who are unaware, as even enlarged, those release handles are not easy to see.)
Here's a view of the underbody (AB brake system) on a mostly scratchbuilt boxcar...
...and with the unpainted handle, left of the door, barely noticeable beneath the sidesill (and almost lined-up with a signpost on the other side of the track)...
This modified Athearn caboose (also AB brake system) got the release rod handles, too,...
...and with the handle visible (barely) in this view...
I recently re-built a dozen Bowser (formerly Stewart) channel-side 65 ton hoppers, modified to represent models of TH&B's 1500 hoppers of a similar style.
Five of the cars have AB brake systems, while the other seven use split-K type brakes, some as detail parts from Tichy, and the rest as K-type brake gear (also from Tichy) modified into split-Ks by cutting off the air reservoir and postioning it alone under the cars' slope sheets. All 12 cars have release rods, barely visible (and not really connected to any of the brake gear), as it's very hard to see much of the details under slope sheets on a black car...
Here's one of the cars upgraded with AB brakes, the release handle in the small gusset plate just above the springs in the left truck...
...and one of the hoppers with split-K brake gear...
...with the release handle barely visible above and to the right, of the car's right truck.
A look at the end of a car also reveals little of what's under there....
While it's not all that difficult to add the release rods, I doubt very much that I'll bother to do many of the four hundred-or-so remaining cars.
Wayne
Ok, Wayne....yeah, I see you agree that it's probably in the range of 3/8" to 1/2". Seems like that's stiff enough to operate the valve and robust enough to handle an occasional unintended whack (!). Like you, I probably won't go to this detail on every car, but I find myself really getting "into the weeds" on this one, a 1905/06-era 6,000 gal. frame-less tank car.
Thanks for detailed reply and photos. Your modeling work is terrific!
-Chuck
Thanks for your comments, Chuck.
I'm looking forward to your versions of this often overlooked detail, too.
Its very small diameter, 1/2" or smaller.
Dave H. Painted side goes up. My website : wnbranch.com