Fw: Atlantic Coast Line R-1 4-8-4's

nw-mailing-list at nwhs.org nw-mailing-list at nwhs.org
Wed Oct 26 22:19:10 EDT 2005

I don't know that the ACL experience would have been all that
valuable to N&W in designing the J's counterbalancing.

The ACL wanted the R-1 to run 90 MPH, a driving wheel rpm of about
378 - they probably figured 400 or 410 RPM for a maximum.

N&W's requirements were different. They needed approximately 500
driving wheel rpm for the J to run 100 MPH (with new tires for a full
70" diameter driving wheel - 105 MPH equals 504 RPM), which was
desirable on the Norfolk and Scioto Divisions; quite probably the
design parameter was for 510 or 515 RPM.

So counterbalancing was much more critical for the J than for the
R-1. But on its side, the N&W was going to use Timken High-Dynamic
steel - a lightweight alloy.

Voyce Glaze told me that Charles Faris did the calculation work on
the J's counterbalancing (I'm sure he was assisted by Gurdon
McGavock), and that he (Glaze) was made very nervous when he was
called upon to check Faris' work. He accomplished well, however; his
fears were groundless.

But no one said anything about using the AAR's formulas; they might
have, but if they did they used them for guidelines and did their own

Ed King

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