--- In STMFC@..., Anthony Thompson <thompson@...> wrote:

Rob Kirkham wrote:

Also, I think I have heard the Standard Tank bolster/saddle part
described as a diaphragm. Maybe I'm wrong about that - its a vague
memory. Any comments on the unique (I perceive) design used by
Standard and the correct nomenclature for it?

Rob, it's a distinctive and even signature appearance,
unmistakable as a Standard Tank design, but functionally not unlike
other builders' designs, as a combined bolster and tank saddle. I've
never heard it called a "diaphragm."

Tony Thompson

Is it too late for me to chime in here? "Diaphragm" is a fabricator's
term, possibly now archaic, for a web that spaces structural members.
Used in this manner, any built-up bolster consists of four pressed
steel diaphragms, top and bottom cover plates, a center filler and
possibly end fillers. The usage of the term is correct, but hardly
unique to the Standard Tank Car Co. bolsters.

Dennis