Steam & Excursion > Roller bearings, steam locos and maintenance advantages.

The main advantage of ( lateral controlling rollers ---- like Timken's tapered roller bearings) is the more elegant that end-wise thrusts are 'rolled'  ( from the rotating element to the fixed, outer race), to distribute the end-loading forces.  Once the bearings were devised and developed, housings could surround the susceptible rolling elements to keep out the grit, dirt and water.

However, the real economic advantages can only be gained when applied to all or most of a RR's fleet of steamers, like was stabled by the Norfolk and Western RR.   With large numbers of plain bearings equipped locos large maintenance forces were required to keep the plain-bearing engines' driving boxes well maintained.

The typical plain bearings driving boxes were lubricated by grease-block technology. That system uses a hard grease cake that is fitted to the bottom of each driving axle, the grease is evenly applied to the bearing surface through a well-fitted steel, perforated screen. Thus, as the axle rotates against the the fixed brass bearing block ( covering the top half of the axle), the two rubbing surfaces soon warm up, the surface of the grease block softens and the spring under the block pushes a small amount of grease against the axle, thus lubricating the rubbing surfaces.

Grease blocks wore at different rates, even on the same engine.  Every trip ended ( in the roundhouse, over a pit) with a detailed inspection of all the critical frame components, bolts, brake rigging and bearing grease blocks, as well as ash pan/fire pan integrity, trailer truck, drawbar components and tender underframe inspections.  With hundreds of grease block-equipped engines in the fleet, that resulted in thousands of individual grease blocks that often had to be replaced as the grease was consumed.
Replacing hundreds of individual grease blocks, across the whole fleet, everyday is very time consuming and labor intensive

SP's solution to their fleet used precision cast and machined driving box axle brasses that were babbitt-lined on the axle bearing portion.  They matched that bearing design with oil lubricated rug-like pads pushed up against the bottom axle surface.  The pads were well oil soaked, and feeder capillary systems ( from the oil reservoirs) continually wicked oil up to the rubbing surface.

The oil 'cellars' had water drains, since oil is lighter than water, as well as easily filled, capped, filler pipes.  With thousands of axle bearings now easily maintained, a huge labor savings was able to be realized.   

Plain bearings consist of two methods of handling rotative axle loading, the cylindrical axle surface, and end-thrust rubbing surfaces. The end thrust problem was never able to be solved, but was tolerated as a simple fact of life.  There must be space between the inner wheel hub and the surface it slams into, as the axle slides back and forth.... Various oil feeding schemes are used as well as improvised greasing arrangements.  The familiar long-spout oil cans were primarily intended for reaching the inner hub area, thus typical poses of engineers with long spouts.  Search for pictures of the men actually using the long spout to get to the hub areas.  

Many driving boxes were equipped with oil reservoirs ( for the hub liners) in the their tops, these could be refilled during Station stops, etc.  Some were individually fed by distribution lines from a car-oil large mechanical lubricators, mounted on many '
'modern' steam locos.

The end battering that the bearings have to absorb are the main source of problems with these types of bearings.  The end thrust problems were particularly pronounced on the pilot truck axles, as they led the loco frame through curves and track switches.
Plain bearings in this application were a continual source of overheating, breaking and related miseries.

Some rollers are simply cyldrical rollers revolving around the axles, with brass blocks at the outer ends of the axles for lateral 'control'----- GM's (former) Hyatt Bearings Division was the main supplier of these, cyndrical-type of axle roller bearings.
Virtually every EMD diesel manufactured in the hay-day of the diesel revolution was sold with Hyatts.

To be continued... and corrected, later

​W.
 

Wes,

Remember that the SP designed & patented "Sadco" oil lubricated bearings were also pressure fed from a machine oil mechanical lubricator, with to oil pressure being fed to the top forward portion of the crown bearing.

Lately some "grease block" engines have been converted over to oil and unless I haven't heard, they seem to be doing very well.  There seems to be a couple new PB&J oils out there that are doing the job.
If we were still at the point where 1522 was torn down for her last crown brass work, I think we would have been doing well to convert her to oil.
We had a small supply of Texaco Hi-Tex 8 block grease left.  We had never been able to find another hard soap based grease that would do as well as the Texaco product under sustained track speed running.  Lots of promises, but none of them were as good.
If I were restoring an engine today, oil would be my choice.

Very interested in this subject Wes. Looking forward to the next update

Posted from iPhone

Re: 'Sadco', above...


Jack,

What you describe sounds very much like the SP wanted that oil flow to be able to work its way to the driver hubs.
Any viscosity, or modern lubricants ( for this service) preference for the 4449?  
Apparently, Dick Jensen used a lot of STP on his axles.

Where I'm going with this discussion is that SP, and some other roads, solved a very difficult lubrication problem that could improve the vast majority of their locomotive fleet.  They had a huge, system-wide maintenance staff, that could have spent lots of man/hours just on changing-out thousands of consumed grease block cellars, every week.

So,  the compartitve benefits of buying roller bearings on new construction locos would not have been as big a benefit to the SP fleet, that had all been previously 'upgraded' to oil cellars, and attendant additional features, as above.....

As I've hinted at , the biggest benefit of axle rollers is on the pilot truck axles ( lateral thrusts), trailer truck, and tender truck axles.

Towards the end of large orders for new steam locos, many orders were spec'd -out for rollers on the small axles and plain bearings on the drivers ----- especially during WW2.  All modern aircraft used similar huge rollers on thier landing gear, especially bombers, like B29s, and the WPB  [ War Production Board] often directed that the larger rollers' manufacturing-output be dedicated to the aircraft and Naval Ship construction industry ...... large propeller shafts, etc..

more to come, on rollers...

​W.

It looks like the 4458 & 59 were spec'd out in 1941, built in '42, possibly before the WPB got up and running.
So maybe SP subsequent locos were caught-up in the WPB restrictions. 
Soon, the diesels were arriving and decimating the huge labor maintenance forces....so, no need to order RB equipped steamers?



Edited 1 time(s). Last edit at 02/19/17 09:38 by wcamp1472.

Thanks for the run down. Some of it I knew but not as clear as you described the whys & hows.

Thanks,


Nudge

wcamp1472 Wrote:
-------------------------------------------------------
> Re: 'Sadco', above...
>
>
> Jack,
>
> What you describe sounds very much like the SP
> wanted that oil flow to be able to work its way to
> the driver hubs.
> Any viscosity, or modern lubricants ( for this
> service) preference for the 4449?

For many years, we used the same journal oil that SP used back in the days of steam, i.e. Texaco HD57, commonly referred to as "Journal oil".  Everything was working fine, until Texaco changed the formula of HD57, to be "more usable/applicable" for roller bearings, since there were "no longer any oil lubricated plain bearings in railroad service". We then switched to a more specialized oil called Moropoa. When that no longer seemed to be doing the job, we now use the PB&J oil, mentioned above. Concerning lubrication of the hub liner, each and every oil cellar box on the SP had/has felt pads mounted in the ends, that are always oil-soaked from the reservoir area in each cellar box. Since the top of the crown bearing was constantly receiving oil under pressure (from the mechanical lubricator), the oil cellar box, with its cotton spring-pad lubrication for the bottom of each axle journal, was ALWAYS receiving additional oil.
 
> Apparently, Dick Jensen used a lot of STP on his
> axles.
>
> Where I'm going with this discussion is that SP,
> and some other roads, solved a very difficult
> lubrication problem that could improve the vast
> majority of their locomotive fleet.  They had a
> huge, system-wide maintenance staff, that could
> have spent lots of man/hours just on changing-out
> thousands of consumed grease block cellars, every
> week.
>
> So,  the compartitve benefits of buying roller
> bearings on new construction locos would not have
> been as big a benefit to the SP fleet, that had
> all been previously 'upgraded' to oil cellars, and
> attendant additional features, as above.....

Also, remember that the SP was NOT really a "high speed" railroad, such as the NYC, PRR, UP, CMStP&P, etc., they really did NOT need the benefits of roller bearings on all axles. The SP designed & patented "pressure feed oil lubrication system with a Babbitt crown bearing" was working just fine for THEIR type of service.

> As I've hinted at , the biggest benefit of axle
> rollers is on the pilot truck axles ( lateral
> thrusts), trailer truck, and tender truck axles.
>
> Towards the end of large orders for new steam
> locos, many orders were spec'd -out for rollers on
> the small axles and plain bearings on the drivers
> ----- especially during WW2.  All modern aircraft
> used similar huge rollers on thier landing gear,
> especially bombers, like B29s, and the WPB  [ War
> Production Board] often directed that the larger
> rollers' manufacturing-output be dedicated to the
> aircraft and Naval Ship construction industry
> ...... large propeller shafts, etc..
>
> more to come, on rollers...
>
> ​W.
>
> It looks like the 4458 & 59 were spec'd out in
> 1941, built in '42, possibly before the WPB got up
> and running.
> So maybe SP subsequent locos were caught-up in the
> WPB restrictions. 

The WPB would not allow the SP to purchase any more "passenger locomotives", i.e. those having 80" diameter drive wheels, so they were forced to purchase additional 4-8-4s classed as GS-6 for "General Service" duties, with smaller drive wheels. Although readily available, the SP chose NOT to specify any additional steam locomotives with roller bearings. Thus, the two GS-5 "Daylights" were the only two steam locomotives in the history of Southern Pacific that were equipped with roller bearings on all axles.

> Soon, the diesels were arriving and decimating the
> huge labor maintenance forces....so, no need to
> order RB equipped steamers?

By the way, I forgot to add that the SP's "Sadco" Babbitt bearing process is still in use to this day, and was/is the basis for ALL traction motor support bearings, whether Alco, EMD, or GE, manufactured by Magnus Metals Co., until roller support bearings were developed for, and introduced on, AC three phase induction traction motors.

Jack...

You forgot about crankshaft and common rod bearings used in virtually ALL, piston driven, aoutomobile, truck locomotive and larger engines.  Virtually all are babbitt-lined....

With auto engines, rolling-element bearings would never hold up under the hiigh crankshaft loads & speeds...
Plus, how do you slide "the rollers" deeper than the two ends of the crankshaft?
How do you get them around the cranks & counterweights, to the center conn rods?

So, pressure lubricated, plain bearings RULE the World, not the Donald....

Also, what kind of bearings support the shafts of the turbos?  Think a roller could do THAT job?


​W.

All I can say is that after years of struggling non stop to keep the T-1's running with those awful Hennessey lubricators, and countless nights with guys on their backs in the ballast under them fiddling with those darn contraptions  and then to have the absolute pleasure of going to the all Timken roller bearing equipped 614 was like going to steam heaven. Service the rollers on Friday, run all weekend at track speed and never have to touch anything 'till the following Friday to get ready for the next weekend and with the added reservoirs for the mechanical lubricators be able to run 1,500 miles without any servicing.

   After the plain bearing T-1's....pure heaven. May I NEVER have to go back to a non roller bearing locomotive.  Ross Rowland

Thank you Wes and Jack for some fine explanations of bearing technology and lubrication.  Probably few bearing installations took as much beating as the bearings all around on steam engines.

Wes,

The types of oil lubricated axle bearings on steam locomotives can not be compared to internal combustion crankshaft and/or connecting rod bearings, as the crankshaft & rod bearings in automotive gasoline and/or diesel engines are full circle bearings. Thus, there is hydrodynamic lubrication, where the journal in question does NOT actually contact the 360 degree circumferential bearing structure, i.e. the journal is actually supported by an EXTREMELY high pressure film of oil, created by the rotational speed of said journal. The locomotive crown bearings are open on the bottom.

Yes Wes, roller bearing cranks would never hold up in an automotive engine which explains why just such
an application in high rpm VW race motors was so successful. Never, the word anyway, usually doesn't hold much water.

Out

I think I used the ,Virtually all'....I don't remember using  'never'



W.

Here's your line Wes!

"With auto engines, rolling-element bearings would never hold up under the hiigh crankshaft loads & speeds.."

Which is of course interesting since that's exactly why rollers were used. Stick to trains!

Out

In response to wcamp1472,

If you look at a turboshaft engine (a P&W PT-6 is a good example), there are a couple types of roller bearings in use.  The shafts in the center of the motor/engine are supported with flat roller bearings to combat the run-out forces generated so as to keep the shafts in line.  The ends of the shafts are supported in a ball bearing assembly so as to combat the thrust forces generated by the spinning turnines (since they really are nothing more than over energetic fans) trying to push one way or another.  

A reciprocating engine crankshaft could in theory use a roller assembly.  If you look at some propellers (the variable pitch kind) out there, they use a ball bearing that is like a "snake" of sorts.  The balls themselves are retained in a flexible metal strip (yes, they can come loose so care is needed for install or removal) that can be straightened or twisted as needed to be able to install or remove them from the blade/hub mating groove.

As for turbo chargers, there are some using rollers (the ball type from what I've seen in a quick internet image search).  I assume that the type pictured are used for the same reasons as mentioned in the first part of this post, for counteracting the thrust forces generated.

Hopefully this clears the mud some,
Southern3205

And Wes, I'm just teasing you, I have nothing but complete respect for your knowledge of steam locomotives.
As for the VW roller motor, we lost an oil pump, pressure switch interlock shut the ignition off and surprisingly
we didn't lose the crank. We went to a flat bearing design because the bearings got so expensive but they did
work well.

Out

German Tiger tanks used full roller cranks in WW2. Really neat watching them restore one. Major PIA. 
Typical over engineering the Krauts did. PS I'm a Kraut.
Enjoy every post on your tech:)