Re: NNG: Big Boy 4014 Update

Casey Akin Wrote:
-------------------------------------------------------
> Mike Wrote:
> --------------------------------------------------
> -----
> > Casey to my knowledge all of the 4000, 3000,
> and
> > 800 class locomotives on the UP were equipped
> with
> > roller bearings on the axles, but not on the
> rods.
> > The 844 has plain bearings on the rods as does
> the
> > 3985.
>
> So, would roller bearings be able to handle the
> back and fourth motion of the side rods? Is there
> a reason brasses were used as apposed to rollers?
> It just seems like the better and more reliable
> choice to use roller bearings. I am no rocket
> surgeon, and I also have no idea what I am talking
> about!
>
> Casey


Well in all honesty Casey from doing some reading on this, it really just comes down to the builder's specification. The reason why they wanted roller bearings on the axles was to save in maintenance costs and wear. Essentially with roller bearings being fed by a mechanical lubricator like on the 844 you don't have to worry about having to check the grease boxes, etc. Its all self contained and easy to work with.

Now the reason for the plain bearings on the side rods, again from what I read, was really just a choice the UP decided to go with. Roller bearings on the rods were not needed and were found by the UP to be more trouble to deal with than what they were worth. And since most trips were less than 130 miles they didn't need to worry about greasing up the bushings in the middle of a run or making service stops too much.

Mike Wilson
Michael J. Wilson Photography
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