Steam & Excursion > SP Roller Bearing locos?

Other than the two GS-5s, did Southern Pacific have any other steamers with roller bearings? Includeing tests, temporary / leased power, or refits?

djansson Wrote:
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> Other than the two GS-5s, did Southern Pacific
> have any other steamers with roller bearings?
> Includeing tests, temporary / leased power, or
> refits?

No. The SP designed and patented pressure feed, Babbitted crown brasses system (Sadco) worked VERY well for their types of service.

HotWater Wrote:
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> No. The SP designed and patented pressure feed,
> Babbitted crown brasses system (Sadco) worked VERY
> well for their types of service.

Would SP bearings not have worked well in some
other type of service?

timz Wrote:
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> HotWater Wrote:
> -----------------
>
> > No. The SP designed and patented pressure feed,
> > Babbitted crown brasses system (Sadco) worked
> VERY
> > well for their types of service.
>
> Would SP bearings not have worked well in some
> other type of service?

The SP was not a "high speed" railroad, i.e. rarely exceeding 90 MPH. Now, take railroads like the UP, Santa Fe, NYC, Milwaukee Road, etc., with sustained speeds of 100 MPH or better, then roller bearings became a necessity on the larger, more powerful modern steam locomotives.

It's not so much the 'rolling' surfaces of plain bearings,
that is the cause of problems, its the poor lateral ( parallel to the axles)
pounding that plain bearings are subjected to when navigating
track curves at ‘decent’ speeds.

The driver's inner wheel hubs are highly-polished 
disks on the inside of the wheel hub.  The hubs of the 
wheels contact the plain brass, semicircular: "hub-liners",
which are the bearing 'faces' of the journal boxes....
that match to the wheel hubs.

The hub liners take special arrangements to provide 
lubrication at the wheel hubs

On straight sections of track, the hubs rotate clear of the hub-liners.
The hubs only rub the hub-liners while navigating curves.

Timken's tapered roller bearings are designed to be used in pairs, 
back-to-back, at each wheel.  The inner and outer races are conical,
with tapered rollers surrounding the axle 360-degrees.  

However, a single tapered roller assembly only handles 
end-thrusts that force the rollers more tightly into the tapered races.
For all wheeled vehicles, including autos and trucks, using the tapered
roller bearings, the two complete bearings are mounted back-to back  --- so that either direction that the axle slides, one of the two tapered bearings easily rolls the forces into the structural frames.

The problem of troublesome plain bearings was most pronounced 
on the axles of the two-wheel and 4-wheel pilot trucks. As locos 
got bigger and heavier, the axles of pilot trucks became trouble 
spots ---  as long as they used conventional plain bearings.
The smaller axles and wheels guiding the locos through curves means
that end-wise thrusts are common and can be heavy and severe.

Almost all the PRR K4 locos were upgraded & equipped with roller bearing pilot trucks, during the period of WW2 and after the War.

Timken's tapered rollers solved all the problems of overheated 
pilot truck bearings!  PRR had a program of swapping out the pilot 
trucks of all their engines during the 1930s & 40s; but did not have an
extensive program to re-equip or apply rollers on the other axles.  

The pilot truck-upgrade project had used truck frames that were common to a class of locos.

 Typically, it made sense for PRR to swap-out tender trucks with 
trucks that had been up-graded to standard axle-sized roller bearings.
So, they had a shop that specialized in truck upgrades.

Except for compromised end-loading capabilities, plain bearings 
are very suitable for locomotive service.

W.

 



Edited 2 time(s). Last edit at 04/09/24 18:16 by wcamp1472.

>!  PRR had a program of swapping out the pilot 
> trucks of all their engines during tge 1930s & 40s;
> but did not apply rollers on the other axles.

PRR put roller bearings on pilot trucks -- meaning
four-wheel trucks? On K4's, or M1's, or what?
Is the change visible, looking at the engine?

I don’t know if PRR had a protocol
over whether 2 wheel or 4 wheel
pilot trucks for preference.

I discovered the 1361 was equipped
way back in early 1974, when Russ Shipman and I inspected the engine
while on display, inside the fence,
at Horseshoe Curve.

We were surveying possible steam locos for possible use by the American Freedom Train.

Our report to Ross was that the amount of work necessary for that engine and the 3750, moved them to the bottom of our list of candidates.
It would have taken the 2, K4 locos
to safely power the AFT.

We had made prior arrangements
to gain access to the engine.

No, there is no identifying evidence
on the outside of the pilot wheels,
that would differentiate the axles
as being roller-equipped.

Special castings were necessary
to adapt the ‘boxes so that the
up-grade could be a simple changeout of the axle-sets,
easily accomplished at roundhouses
that had drop tables.

PRR would have wanted to, as quickly as possible get the wheel sets changed, “in the field”.

Are they readily identifiable from the outside?
No.

However, looking over the top of
pilot truck frame, & looking at the axles, the fully-enclosed roller bearing journal boxes are plainly visible.

Very good news.
On my next visit to Pa, State RR
Museum, I’ll make an inventory of
roller-up graded, steam loco
pilot truck axles.

W.

Posted from iPhone

SP's clever switch to oil-lubricated driver axles solved a 
huge and expensive problem with grease-block driver 
journal lubrication.  

Every conventional driver axle at the time used blocks of grease 
that had a concave surface that kept the axle journals lubricated 
over the full length of the journal bearing surface.  

However, the grease block had a steel 'distribution screen' that 
allowed the full surface of the journal to get even grease application.
As a driver journal began to 'warm-up', the screen 'metered' the grease 
flow, allowing the axke to 'return' to its 'running heat'.

However, grease blocks tended to wear-thin, at random rates. so after 
every trip, when over an inspection pit, a loco could have one or more
grease blocks that were in need of replacing --- too thin for a routine trip.
So, replacing the 'thin' grease blocks was a labor intensive job,
That could take 20 minutes per grease block to be replaced.

SP was spending a lot of labor hours replacing grease blocks,
Every 4-axle engine has 8 grease blocks... across a fleet of hundreds 
of locos, with multiple axles ---- soon you're talking thousands
of grease-blocks needing attention, every day!

So, SP decided to solve the problem on its newer locos,
like cab-forwards and 4-8-2s & 4-8-4s.  They switched to oil lubricated 
 driver journal boxes.. The driver journal boxes were fitted with round sight 
glassses so the inspectors could check the oil levels.  Any thst were 'low',
were easily and quickly re-filled.

Also, oil was fed under pumped pressure to the wheel-hubs to provide 
ample lubrication at the hub liners.

However, not every SP loco was oil-cellar equipped, so
manual labor and a substantial workforce was required.
Because of that large work force, adopting roller bearings for locos 
would NOT materially reduce that labor force.  No matter 
how many new locos they bought, if roller-equipped ,
they still had thousands of grease-blocks that needed inspecting.

So, SP avoided investing in roller-bearing equipped locos.
A different solution was coming out of LaGrange, Illinois.

Their ingenious oil-lubricated systems had worked very well.
But, when diesels came around .... it meant thousands of roundhouse
jobs could be eliminated... No more axle  and grease-block problems,...

And, millions of dollars of employees' tax-withholding dollars no longer 
had to be sent to Washington---- every 90 days...

That diesel air horn meant a lot more than just being annoying!

​W.

not proofed yet ...



Edited 1 time(s). Last edit at 04/09/24 19:21 by wcamp1472.

After our pilot truck issues early on, we decided to convert ouf pilot truck to roller bearings.   I talked to Doyle and sent him our drawings of the journal boxes and he had new ones cast at a foundry out that way.   He shipped them to us and we machined them at the company I and my fireman worked.   We used Amfleet wheelsets/beearings fit to the boxes and that cured all problems we had with the Hennessy lube system.  We also fine tuned the tram, etc on the pilot truck.  Later on, we converted the trailing truck and the tender trucks to rollers.
It would have taken major frame modifications to convert the drivers.  We eventually reworked the boxes and rechecked the tram and installed new crown brass.  We stayed with the grease cakes which were a PIA.  We kept a supply of them pressed and boxed in the tool car made with Hi-Tex 8 which Doyle sent us.  Any of the contemporary grease we tried was a loser compared to the Texaco.  We used it for rod dope and it worked fine for that.  1522 always ran warm on the drivers, sometimes up to 225 deg.  Had the oil fed system now used on 4501 and other engines been proven back then, we would have gone that direction but it hadn't been really tried yet to any degree
Doyle proved to be a big help to us with our project.  His donation of the grease for the cakes saved the day for us.  The foundry he used did a beautiful job on the pilot truck boxes.

Post SP ownership but 4449 has roller bearings on all axles today.

Modification..
4449 has rollers on all axles , EXCEPT the driver axles 
which still roll on SP's oil lubricated,  plain bearings and pressured 
oil fed to the axles and hub liners..

Very satisfactory.

​W.

 

The OHRF has to file a waiver with the FRA to get 4449 cleared to run on mainline track, because of the solid bearings. Doyle once lamented that when the city of Portland asked SP for a "big display engine", SP grabbed the first GS engine off the Bakersfield deadline.  But the SECOND GS was one of the GS-5s! Had they gotten that one, a LOT of legal issues would have been done away with.

djansson Wrote:
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> The OHRF has to file a waiver with the FRA to get
> 4449 cleared to run on mainline track, because of
> the solid bearings.

May I ask just who told you THAT??????  In all the years I was with the 4449, we NEVER had to "file a waver with the FRA"!!!!

Doyle once lamented that when
> the city of Portland asked SP for a "big display
> engine", SP grabbed the first GS engine off the
> Bakersfield deadline.  But the SECOND GS was one
> of the GS-5s! Had they gotten that one, a LOT of
> legal issues would have been done away with.

Again, who told you THAT????