J Class Changes
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Tue Sep 2 17:14:12 EDT 2008
Thanks to Bud Jeffries for the details on the J rod replacements. I write
most of my comments from my computer at work, and my reference books are at
home. I forgot about the 610 getting new rods. I should keep my first
edition of Bud's book at work.
Bud--Were these rods cast in Roanoke shops, and who designed the change?
Subject: Re: J Class Changes
> Dave is correct, there were four J's that got the redesigned single rods:
> 600, 605, 610 and 611. These were applied from 1952 to 1956-7 as needed
> when a stress fracture appeared on a crankpin. This rod change involved
> replacing the front, rear and intermediate side rods, the main and
> eccentric rods, the intermediate driving wheels, and all of the crankpins.
> This was very costly, therefore was only done when required. These rods
> were designed in 1952 and were not interchangeable with tandem rods.
> Other changes noticeable on the J's. Previously someone wrote about the
> change in design of the steps on the pilot and this was done beginning in
> 1944. The bell was moved from the boiler top in the cowling to the pilot
> deck in front of the left cylinder; this treatment was applied to the
> streamlined K2's as well beginning in 1953. And the spoke pilot wheels
> began being replaced in 1948 for the first 11 J's with solid rolled steel
> wheels; the 611-13 get these as built. Beginning in 1953 these wheels were
> replaced with cast steel wheels that were also solid.
> One J, no. 602, was built in 1942 with a trailer truck booster which
> required some external piping. This was removed in December 1945 along
> with the piping.
> Of course the six J-1's were built in 1943 with heavy non-roller bearing
> rods and not being streamlined. From September to November 1944, the J-1's
> were streamlined, received lightweight roller bearing rods and then
> classed as J.
> These were the visible changes. There were quite a few changes that were
> not visible.
> Bud Jeffries
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