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

nw-mailing-list at nw-mailing-list at
Tue Oct 25 15:26:19 EDT 2005

>Ladies and Gentlemen,

>I'd think that N&W's K-3 counterbalancing problems were far more a factor


>lessons learned when designing the J than anything that occurred on the ACL

>with their Baldwin R-1's (or any other non-N&W designed locomotive for that



>Ed Painter Jr ; Narrows, Va (currently Russellville, AR)


No doubt N&W learned plenty from the K-3's, but the balancing problems with
the K-3's were never corrected so they only provided a lesson in what NOT to

The ACL R-1's were modern, high-speed 4-8-4's which were balanced according
to the latest AAR guidance (which was theoretically at least something all
the railroads followed, not just Baldwin and/or the ACL). The balancing
problem was corrected by modifications to the engines after extensive study
of the problem. Hence, the R-1's showed both the problem and how to correct

Another point is that it wasn't any big mystery why the K-3's had problems-
a low-drivered 4-8-2 with a LONG main rod is just gonna be really hard to
balance satisfactorily. The deal with the ACL engines is that they weren't
expected to have any problems. They unfortunately showed that the theory
(or at least the recommendations) hadn't kept up with the real world.

It's been written that the N&W design team looked at all the other existing
4-8-4 designs while designing the J's, and the ACL's engines would have
certainly been among the 4-8-4's the studied. Given that the J's used a
whole range of innovations to ensure they didn't have balance problems (see
Bill Withuhn's article in "Railfan" some years ago) and were suitable for
higher speeds than any other 70" drivered engine ever built, it only makes
sense that the N&W design team studied the R-1's too.


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