---In STMFC@..., <fgexbill@...> wrote :
> I really like the stiffness the SS wire would bring to the sides, a vulnerable area.
> I ordered my .019 ID SS tubing from "Small Parts," now "Amazon something"
> and it was supposed to come yesterday. It is spec'ed with an OD of .025 so
> I am afraid it will look clunky. Tom would you please share your tubing source
> and Part#? Thank you for posting the link.
Hmmmm. The 0.020" ID SS tubing has an OD of 0.028". That's the tubing I use to splice 0.019" handrails and is what's shown in the photo linked to my previous post. The next size down in the product line is 0.017" ID and 0.025" OD. If that's the size you ordered it will be fine for use with 0.015" handrails but not 0.019". The wall thickness on both sizes of tubing is 0.004". Seems to me a 0.028" OD splice on a 0.019" handrail (47% oversize) would be less visually distracting than an 0.025" OD splice on a 0.015" handrail (67% oversize).
The Resin Car Works web site has a couple of very useful late 1930's ACF drawings with all the pipe sizes called out. This one, from 1936, shows a tank car AB brake system:
And this 1939 drawing shows a dome platform and ladder:
All the railings and the train air line are 1 1/4" pipe. The supply line (branch pipe?) from the train air line to the brake valve is 1" pipe, and the air lines from the valve to the air reservoir and brake cylinder are 3/4" pipe.
Not sure why there's confusion on what wire size represents each of those pipe sizes in HO. Detail Associates prints that information on the packaging for all of their brass wire sizes: 0.012" wire represents 3/4" iron pipe, 0.015" represents 1" pipe and 0.019" represents 1 1/4" pipe.