On that note.... I was internet-stumbling somewhere and ran across a commentary about some of the technical considerations to roller bearing applications on steam locomotives that got into the fundamental weakness of both roller and ball bearings. I.E. while they're excellent for bearing loads radial with the bearing, they are horrible about surviving any type of side-loading. Hence, the design of the tapered bearing race to manage both axial and radial loads. But then the second problem rears it's head. Tapered bearings aren't intended to have any play (to speak of) in the assembly. The tolerance stackup and wear stackup in steam locomotive frame assemblies, rod assemblies, etc. etc. etc. demands there be play, and we haven't talked about frame flex with each piston thrust....
Obviously it can be and has been overcome, but it's a subtle and complete redesign, not a drop-in replacement. On a single piece cast steel frame it's likely much more achievable to do rollers on the axles than on a 'slab' style frame.
And that assumes it's an inside frame locomotive. The outside frame K's are dimensionally constrained for bearing surface.
The fact that I've daydreamed at work about what it would take to do something like this is an entirely different proposition altogether and falls entirely into the realm of somehow becoming Mr. Buffet's sole heir....
SRK
Russo Loco Wrote:
-------------------------------------------------------
> Chris Walker Wrote (approximately):
> --------------------------------------------------
>
> > {Why continue} with those brass blocks
> > for axle bearings instead of rollers, and
> > {not} putting rollers on the main rods?
>
> SR_Krause Wrote:
> --------------------------------------------------
> -----
> >
. . . I'll point out that rollers
> on the rods are
> > bulky & heavy and add to the rotating mass
> > that has to be balanced
. . .
>
>
> The S.P. tried roller bearings on the axles
> – NOT the rods – of their last two
>
Daylight 4-8-4's* -
>
>
. . . and found that the improvement
> over their patented oil cellars wasn't enough to
> justify the cost. IIRC, the C&TS has been
> replacing the grease block axle lubrication of
> their K-36's with oil cellars as the engines go
> through the shop for major overhauls, as this not
> only reduces friction but also eliminates the
> tedious process of lowering the binders frequently
> to renew the grease blocks.
>
> -
Roosso
>
> * #4458 (Timkin) and #4459 (Symington)
