But radial is so much easier to type than circum... whatever.

Jim Hayes
Portland Oregon
www.sunshinekits.com


On Mon, Jun 21, 2010 at 4:51 PM, Kurt Laughlin <fleeta@...> wrote:

----- Original Message -----
From: Tim O'Connor
. . . And the earlier cars looked very
different, since many (most?) of them had radial rivet seams
(around the diameter of the tank) instead of horizontal seams
like the ACF Types 21 and 27.

----- Original Message -----

This is one of those annoying misnomers that probably bugs me as much
"Bettendorf trucks", "outside framed boxcar", or "PRR X-29 boxcar" does
others. (*)

There are three directions on a cylinder: axial/longitudinal, radial, and
tangential/circumferential. Most riveted tank cars have longitudinal seams,

some had circumferential seams. The only radial seams would be those caused

by making the heads out of multiple pieces. Some have suggested that radial

refers to the direction of the rivet axes on circumferentially seamed cars,

but that would be true for longitudinal seams as well.

Oh well.

KL

(*) I take that back. There is very little in my life that causes me to
react to the extent that some people do when reading these terms.

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