Bearings Question

[Overmod]

Firelock76

When the dry-process copiers were invented one of those components was eliminated, specifically the toner. However, the name "toner" stuck to the dry powder that's loaded into todays machines, which should be called developer.

According to Xerox patent history, when copy technology went from wet to dry process the "toner" was the colored powder component of the "developer" (see the Walkup patent, 2638416, and Lehman 3336905) and it is not entirely surprising to me that when separate carrier was no longer needed in a two-part developer, and 'toner' was the only material needed to develop the electrostatic image prior to fixing, the industry distinguished it from earlier developer.  I will certainly grant you that, semantically and historically, 'developer' is a better word for what the stuff does.

[AgentKid]

SD70Dude

Names stick around, several of our yards still have a "steam track" or "icehouse lead" even though it's been decades since everything ice or steam related was removed.

I really enjoyed both Jeff's and dude's comments.

Before the Calgary Herald became the last user of an industrial lead a couple of years ago, and the lead removed, the switch was always referred to on the radio as "Titian" a station in the ETT's that disappeared back in the 60's.

In our house, growing up, there were any number of expresions my Dad used from work. For instance, when he wanted to tell us when to be ready to drive one of us to the many places dads have to drive their kids, we were told the ride was "supplied for 8:15".

Traditions on the railway work the other way as well. Alyth was opened in 1899 to replace the original "Calgary" yard, and caboose maintainance was moved as well. What had been the original Caboose Track always kept that name. During the annual slowdown before the fall grain rush would start, spare cabooses would be moved from Alyth up to the Caboose Track, but what was even more amazing, is that according to various sources, there were cabooses parked on that track every year unitil caboose use ended in 1990. Apparently, that track was never used for anything else, it was a violation of an unwritten rule, or a law of nature, or something.

Bruce

 

[Firelock76]

And I'm sure many of us know, or have known, members of the World War Two generation who still call refridgerators "iceboxes."

[SD70Dude]

A failed and/or overheated roller bearing is still called a "hot box", even though it is not square or rectangular in shape.  And though their official name is "Wayside Inspection System" everyone still calls them "hot box detectors". 

Names stick around, several of our yards still have a "steam track" or "icehouse lead" even though it's been decades since everything ice or steam related was removed. 

I've always called them "plain bearings", but have heard the term "friction bearing" used too.

[Firelock76]

Who knows how things get the names the do, and how they stick?

Anyone remember the old liquid-process copiers from 30+ years ago?  The development process involved two components, developer and toner.  When the dry-process copiers were invented one of those components was eliminated, specifically the toner.  However, the name "toner" stuck to the dry powder that's loaded into todays machines, which should be called developer.  Makes no sense, but that's the way it is.

Take it from one in the trade.

[jeffhergert]

Firelock76

I think I see where SPer's coming from, I've heard the term "friction bearing" myself, scratched my head over it too, but I believe it refers only to the old "axle rotating in oil-soaked waste" brass/bronze with babbit metal lining bearings used on freight and passenger cars before roller bearings came into common use.

 

 

I also, have heard and used "friction bearing" for the old, non-roller bearing axles.  And I will probably continue to use the term.  So it's not correct.  Many things, especially in railroading, use simplified or archaic terms.  The thing is, those that use the stuff in the field know what a person is talking about.

Take "triple valve" for instance.  The last true triple valve was outlawed years ago.  The correct term is "control valve".  I'm sure in the higher and more technical echelons of railroading, control valve is used.  Out in the field, however, you'll hear "triple valve" from the likes of train crews, dispatchers, and even carmen.

Jeff 

[Firelock76]

Hot stuff Wanswheel!  Looks like you're back with us!

[wanswheel]

Expanding vocabulary.

https://ia801300.us.archive.org/BookReader/BookReaderImages.php?zip=/29/items/ENGINEERINGTRIBOLOGY/ENGINEERING%20TRIBOLOGY_jp2.zip&file=ENGINEERING%20TRIBOLOGY_jp2/ENGINEERING%20TRIBOLOGY_0026.jp2&scale=2&rotate=0

https://archive.org/details/ENGINEERINGTRIBOLOGY

[Overmod]

Here is the story in brief.  (Well, relative brief.)   The bearings that use brasses, whether lined or not, fully circumferential or not, are all 'plain bearings' (or, if you want to be technical and accused of pedantry, 'hydrodynamic bearings') regardless of the method that is used to lubricate them (wicks vs. pads, oil vs. grease, etc.)

The actual 'bearing' in all of them is a comparatively thin film of lubricant, usually oil or the oil component of a grease, compressed to a wedge and then to a pressurized film between the face of the brass and the steel axle journal, holding them apart.  There are very good reasons why the crown and liners are made of brass, bronze, or white metal: any asperities in the lubricant that might break the film and cause scratching between two hard faces will instead embed in the softer material to the point the film forms over them.  This is a different mechanism from slow-speed bearings, in clocks for example, where this process only turns the softer material into a comparatively effective lap that preferentially eats the journal surfaces.

An important thing to remember is that once the hydrodynamic film has formed and come up in temperature to reasonable viscosity, the plain bearing generally has less resistance to motion than a roller or ball bearing of equivalent carrying capacity, and of course is less prone to damage by spalling or breaking should any dirt get into the tribology (or shock or jerk be communicated to the essentially line contacts between rollers and races).  The catch, of course -- one of the reasons roller bearings with M942 lube became standard on interchange cars -- is that the lube film has to remain full and intact.  Hairs from the waste or pad, or inadequate oil, will rapidly cause the bearing surface to go into thermal runaway with the result being an infamous hotbox (or worse).

Now, it was recognized no later than the 1840s that using rolling elements between the bearing and journal would give all the good effect of the Winans 'friction wheel' (which of course was an antifriction wheel - see White if you aren't familiar with it) -- the problem was that the same poor materials science that made the Winans design short-lived also affected the strength of the balls or rollers used as bearing elements... and a roller bearing with deflicted rollers becomes the most friction-heated device of all, comparatively fast and with comparatively little warning.

Now, when metallurgy permitted, the Timken people developed the principle of the tapered roller (as opposed to SKF, which uses barrel-shaped rollers to give self-alignment, the reason these make better driving-box bearings on many large modern steam locomotives) and they marketed their system as 'antifriction bearings' (which of course they are).  The problem was that it was too easy to then allow, or portray, the alternative as the "antonym" of antifriction... which the undiscerning will swallow as 'friction'. 

Don't you be undiscerning.  There is no such thing as a 'friction bearing' as an alternative to rollers or any other bearing tribology.  And if you think hydrodynamic lubrication is inferior to rollers... consider what is used in any practical internal-combustion motor for internal rotating or variably-loading contact, and what historically happens except in very unusual and expensive circumstances when folks get carried away and spec roller or ball bearings there.

By extension, consider the system used by Union Pacific for reliable high-speed rod lubrication on the later FEF classes, specifically as an alternative to large-eye narrow-section Timken roller rods.  Pay careful attention to the floating bronze bushing with all the holes drilled in it to serve as grease cellars of a sort.  While this isn't quite as good at 120mph as the high-dynamic lightweight rods and very thin rollers, it isn't nearly as subject to dramatic bending failure at speed, either.  And since a few hp loss in the rod bearings isn't of that much moment (pun not intended) but reliable management of clearances in what may involve substantial differential heating of parts of rods is, the experiments in China and elsewhere, in the 1950s, to implement the principle of full pressure oiling to rod bearings takes on substantial importance.  Why it is not far more utilized than it is is something of a mystery to me.

As a note: use of roller bearings on trailing trucks of steam locomotives came comparatively late, as the ashpan heat and dirt made oil lubrication a rather uncertain thing and the advantages of rollers relatively slight there.  Likewise tender trucks exposed to spilled and perhaps caustically-treated water, or worse to frequent spray from track pans, are not going to be happy with rollers, and the substantial first cost of those bearings argues against them if not needed for high-stress alignment.  The advantages on driving axles are substantial and fairly immediate, but short-lived indeed if you don't use Franklin self-adjusting wedges (or English-style very frequent maintenance, which seldom pays for itself in North American practice) to keep everything in tram.  Hence the fun with the early T1s drinking the Hennessy Lubricator Kool-Aid ... and yes, as long as you keep those things full and adjusted they give good practical results.

[Firelock76]

I think I see where SPer's coming from, I've heard the term "friction bearing" myself, scratched my head over it too, but I believe it refers only to the old "axle rotating in oil-soaked waste" brass/bronze with babbit metal lining bearings used on freight and passenger cars before roller bearings came into common use.

 

[Overmod]

Don't call them 'friction' - they are 'plain' bearings.  Roller bearings are 'antifriction' but that only makes 'friction' the opposite if you are a Timken salesman.

The three 'early' surviving Reading T1s have some plain bearings, whereas 2124 is 'all roller'.

[SPer]

Are any surviving large steam locomotives besides 4449 has friction bearings on loco and tender axles