Steam & Excursion > How many friction trucks can you name?

Ely NV

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What is a "friction truck"? 

All, but the caboose.

I prefer to call them 'plain bearings'.
Since the fixed element of the bearing rides on a 100% thin
film of oil, there is never any contact between the axle and the besring.
EXCEPT WHEN PARKED FOR EXTENDED PERIODS.

The same besrings as automotive crankshafts riding on oil film, supplied 
under pressure by the oil pump.  Every internal combustion engine in 
the world uses plain besrings on the crankshaft .... 4, 6, 8, 10, 12 & 16 cylinders...

You cannot offer freight cars equipped with them in interchange
to other RRs, but they can be very serviceable on the "home" rails.

The biggest risks are standing idle for extended periods, exposing the
bare ares of the steel axles to rusting, and age-deteriorating lube pads.

Old style wool-string packing for the oil pads should be 
disposed and current lube pads applied.
And, yes, they need to be frequently "exercised" to keep well lubricated,
as much as possible.

Also, the foam-filled pads used today, can deteriorate and the foam 
loose it's shape, and pull away from the axies.  About 10 years is
the maximum life of oil soaked lube pads..

Fromer practice had new, foam-fitted pads pre-soaked, and 
submerged in journal oil, for a soak-period of 3 to 4 weeks.

Then, when applied to the journal box, copious make-up oil is added
to the new pads. 

Interestingly, at thermal journal detecting devices (Hot Box Detectors), 
show that plain journals ( when still in interchange) had thermal peaks 1/4 the
amplitude of rolling element besrings.  You can expect that plain bearings
roll along with axle temps very close to ambient temperatures.

Common roller bearing temps have recently been discussed on T/O,
from numbers related to  the E. Palestine, Ohio wreck.
Acceptable roller bearing operating temps are much higher than plain bearings,
at the same track speeds.

Interestingly, steam locos fitted with rollers on tte driver axles will run much cooler---
driver-axle RPMs are much lower account of the lower rotative speeds  --- even 
at speeds over 60-per.. 

So, I heartily approve of events where plain bearings can get excercised,
polished and fairly common use .... passenger or freight!

W.
 



Edited 7 time(s). Last edit at 03/18/23 18:51 by wcamp1472.

Here is what I wrote about "friction bearings" in an old TO post, with some edits:

"According to freight car expert Tony Thompson, (author of numerous books about SP freight cars), the "friction bearing" term was invented by the advertisers of roller bearings when roller bearings started coming into use, no doubt to disparage the conventional types of bearings. The advertising obviously was effective, since "friction bearing" became a widely-used slang term among operating personnel, car toads, etc.  On the other hand, the car builders at the time called the old, conventional bearings "solid bearings" or "plain bearings."

Here is an old reply to my post:

 "John is correct. Some 25 years ago a fellow target shooter who had retired from the D&RGW lent me some old railroad magazines. There where many adds from roller bearing manufactures which compared there products to "Friction Bearings. There where also reports and letters from readers decrying the use of "Friction Bearing" as bogus."



Edited 3 time(s). Last edit at 03/19/23 05:28 by johnsweetser.

The superior aspect of Timken's 'tapered roller bearings' is their
ability to transfer load-bearing capacity from end-wise axle-thrusts.

The inner race is tapered and the rollers precess around the inner race,
transferring any thrusts ( force a tighter pressure) that gets transferred 
to the fixed outer race, also tapered.

However, that feature is only effective in the direction that forces the roller deeper.
Thus, Timken uses two roller bearings, back-to-back, that totally convert the 
end-thrusts into a rolling thrust.  And, that thrust distribution is full 360- degrees.

So, tapered rollers, used in matched pairs, are far superior to plain bearings,
when it comes to lateral thrust capacities.  Sleeve-bearings are effective 
mostly at rolling motions only.

The most common use of tapered roller bearings is in highway vehicles
and their front-wheel axle forces.  Those forces can occur all at once in
normal highway driving..

To me, the most brutal punishment is experienced by the front axles of
highway tractor-trailers.  Their speeds and angular impacts are immense...
but the Timkens keep rolling --- for millions of miles.

So, yes, hot box detectors can detect an overheated bearing, but by 
the time that it becomes evident, its already TOO LATE.
The distance to failure and axle burn-off is very short... under a mile.

A far better indicator of endangered rollers is the super-sonic,
high frequency squealing emitted from spinning roller bearings.  

Both the rollers and the races are case-hardened at manufacture.
But that hardening is only 'skin-deep'...  That hardened layer,
over time,  begins to crack and curl.. so, when spinning, the two
surfaces become rough --- at the microscopic level.

That hardened layer is being ground-away ---- once that stage begins,
the Ultrasonic detection can predict with 100% accuracy which bearings
will fail --- and can predict that ultimate failure to occur in about
100 more miles.  

Why RRs continue to invest in ineffective thermal detectors ,
is a puzzle to me.   

If I was a fund manager of a signicant amount of RR corporate stocks,
I'd beat down management's doors to get them to immediately graduate
to ultra sonic detection of endangered rollers.

Across this land, there are NOW untold hundreds of "ultrasonic squealing"
rollers, as you're reading this. And very few are listening....

The current reasoning of the stock-holding class is that clearing up
the wrecks that occur, is less costly that making the investments in
thousands of miles of a superior roadbed---supposedly, that gamble
results in greater retained profits.  Wrecks are a part of the "costs 
of doing business", is the reasoning.  What's THAT  about ?

Another way to get greater profits is to buy and apply ultrasonic bearing
detection across the entire system.  And especially, within a short distances
of interchanges between carriers... so you find all bad bearings coming onto
your property, from a less-protectected partner/carriers.

[ Ultrasonic detection at interchange points could be a shared cost, between
carriers--- and both would be protected.  I'd also bet that under AAR 
car-repair costs, that replacing bad bearings are the "car owner's expense".]

How many new ultrasonic detectors could NS buy & install for the ALL costs of 
cleaning-up the mess at E. Palestine, Ohio?   
[ Probably buys enough ultrasonic detectors to protect the entire 'lower 48'.]

That wasn't a roadbed problem, that was an axle problem.
 Why not capture & eliminate those identifiable risks to future derailments.
 How much cheaper is relying on out-dated "thermal reporting"..?

New, Ultrasonic Detectors are a damn cheap investment & expense,
to my way of thinking!  You only need a few of them, and they don't
have to be every hundred-miles!

Fund managers that rely on carriers'  "hot box" detectors, are accepting continued
unreasonable risks.  The 'press' and fund managers must demand upgrading now!
That's a management responsibility!

That's it for my tirade.

W.
 



Edited 6 time(s). Last edit at 03/19/23 10:25 by wcamp1472.

I believe the original post was referring to the increadible variety of old "plain bearing" trucks in the dogs breakfast of ore cars running on the Nevada Northern's ore train.  I spent the sub-zero morning a couple of days before this video was shot checking every one of those journals - in the foot deep snow.   There are a LOT of oddball trucks in that string.  Mostly every one is still packed with 50- year old wool waste that still seems to work quite well, thank you.

A spash of oil, a poke with the iron to make sure the packing was still under the bearing, good to go...



Edited 1 time(s). Last edit at 03/19/23 17:20 by Earlk.

Earlk Wrote:
-------------------------------------------------------
> I believe the original post was referring to the
> increadible variety of old "plain bearing" trucks
> in the dogs breakfast of ore cars running on the
> Nevada Northern's ore train.  I spent the
> sub-zero morning a couple of days before this
> video was shot checking every one of those
> journals - in the foot deep snow.   There are a
> LOT of oddball trucks in that string.  Mostly
> every one is still packed with 5- year old wool
> waste that still seems to work quite well, thank
> you.
>
> A spash of oil, a poke with the iron to make sure
> the packing was still under the bearing, good to
> go...

Yep, maintenance is the key.  As a local company advertises, "If you don't schedule your equipment maintenance, your equipment will schedule it for you."