Eastern Railroad Discussion > roller bearings

Well can  anyone  with  a  background  in this  tell me  if  Roller  Bearings  need  lubrication?  Behind  the  three  bolts?  Sealed 'forever'?   Can they  dry  out  with lack of  use?  Hope  someone  here  can  help. Thanks

In my experience, yes, roller bearings need lubrication.
However, only enough lubrication to last several years of use.
RR freight car roller bearings are never re-lubricated "in the field".  
It's too risky, and non-sterile conditions.

Similar to the grease packed rollers in your automobiles.
You don't do any re-greasing of them.  
They make noise when worn.
Then you replace them.

In rail service, typically freight rail, when manufactured, the axle,
wheels and rollers are made up as a set. In use, freight wheels wear-out,
and reach condemning limits before the bearings reach the end
of their 'service life'.

The wheel-axle sets are changed in a car shop, with fresh wheels & roller bearings,
and can be treated as 'new'.  
When pressing-off the old wheels, the bearings come off, too.
Then the axle is inspected, and then can be re-fit with new wheels & bearings.

You will find that roller bearings of all types have 'upper limit' of maximum RPMs,
as typically expected "hours of life"  The "hours" is a figure that reflects the typical
hours that 99.999% of bearings last, when operated below the maximum RPMs.

Freight cars ( and passenger cars, too) NEVER operate anywhere near their
maximum RPMs, as listed in catalogs.  The wheels wear-out first, and when
the wheels are pressed off the axles, the bearings come off, first & are new or
reconditioned, before being installed with new wheels.

Once the used bearings come off the axles, they are sent to special shops that totally 
recondition the roller bearing assemblies, including applying all new, factory,
rollers, as well as new seals. When reconditioned, they can be considered 'new'..
since they will outlast the allowable wear limits of the wheel profile, or
wheel high-flange limits.

However, a tiny percentage of roller bearings get  "into trouble" ,
well before the wheels are condemnable.   As they get into danger,
they emit distinctive, ultra-high frequency, 'squealing', sound waves.

They can run a couple of hundred mies in an ultra-high-frequency sonic, 
 'squealing' state, before they begin to physically over-heat.  
Then, its way too late. 

After a couple of hundred revolutions of running 'hot', they may begin to
physically overheat, at very hot temperstures.  Then, axles will get hot, soften,
 and failure can come in a few further miles.   Often in less distance than the next
thermal, 'hot box detectors' and their 10-mile spacing.  

Meaning, that a bearing-in-distress can pass a thermal detector --- in an
allowable temperature, and then burn-off in the next 5 or 6 miles ----
before reaching the next thermal detector and it's 10-mile spacing.

So, let's review:
Rollers are pre-lubricated and side-seals are applied to keep dirt and contaminants 
out of the races.  The lubrication lasts way longer than the allowable wear of 
the wheel tread or allowable flange height of a wheelset.

If rollers are ever submerged in flood waters --- they are condemned & they must
be taken out of service, and have fresh bearings applied.  They cannot be interchanged
to another carrier with previously 'flooded' bearings.

Freight wheels typically get to worn-out wheels, before the bearings'
'service life' is reached.  In roller bearing catalogs you can see the
predicted hours of service for all bearings that they list.
It's hundreds-of-thousands of hours of continuous spinning ratings.

Someday RR managements will catch-up to the fact that continued use 
of old-technology "hot-box detectors" to report failing rollers is a stupid expectation.

They will either decide to utilize up-to-date, ultrasonic detectors, or the regulating
authorities will require them to install and use the advanced technology detection.

Historically, RR managers wait until they they are legally obligated, before
they act to adopt the obvious.

​W. 
( not proofed, yet)

 



Edited 4 time(s). Last edit at 03/29/23 18:42 by wcamp1472.

What  a  great    complete  and  fact  filled  response!!  Thanks.

Before CSX stopped the practice at Pensacola, FL. Car Inspectors would roll by all inbound trains on both sides.. If they could hear the packing ring on the back of the bearing rattling from being loose, the car got shopped. 
W,   Having been just in Engine Service, I am always wanted to learn more.  Thank you!
Steve



Edited 1 time(s). Last edit at 03/29/23 21:37 by ln844south.

I, too, had wondered about your very question.

Luckily, I spent a big chunk of my life
as a professional RRer, working for several Class 1s, and learning new stuff every day.

That gave me lots of opportunities
to dig-in and research many aspects
of the regulated side of RR mechanical systems, like wheels
bearings, air brakes testing and
trouble shooting, as well as interchanging of rail cars, operating rules and bad weather operations ..
blizzards, derailments, wrecks, etc.

So, yes I’ve had the chance to have
many of my ‘points of confusion’ cleared-up. The simplest of questions can have solutions in
very complex, but basic necessities.

Many of the answers to my simple wonderings have had complex
answers, involved complex systems and required years of refining, before the final solutions
are found and universally applied

The only ‘stupid question’ is the
one you fail to ask. If you’ve wondered about it, you know that
many hundreds of others have wondered the same thing(s).

That’s how James Watt wondered
why there was a clear area at the
spout of his tea-pot, while a condensate cloud formed later:
what was going on, there?

Then he wondered why Newcomen
used a cold water spray inside his
early piston operated, mine water
pump … The world hasn’t been the same since…
( of course, later Watt shifted from steam to electricity — to wonder about and fiddle with, as he sought
understanding.. we measure electrical power in WATTS!)

Often the most simple questions are the hardest to answer.

Thanks for your interest.

W.

( weird word arrangements & sentence breaks are the fault of
my I-phone…)

Posted from iPhone

We gnerally use a B10 and L50 life figures for 10% failure and point at which 50% fail, these numbers are
common in industrial use. I'm not sure what our sales figures reflected but it was mix of pre-lubed sealed
and open requiring lubrication. You find that industries with critical applications are a little more attention
paying than our lovely railroad system.

Out 

Thanks for the greater clarity related to actual service life specs.

Greatly appreciated when it comes to
deepening folks’ levels of understanding.

W.

Posted from iPhone

I'm just concerned that everyone is getting fixated on the roller bearing issue at the expense of all the other far more common causes of train derailments. We could go nuts installing sonic detection equipment every five miles and then be perplexed when the number of derailments hardly changes at all.

Posted from iPhone

Another sign of a pending bearing failure is to observe the wheel. Seal failure will allow grease to be expelled and dirt to enter.
Some grease around the seal is allowable, but excessive amount is a possible seal failure. Also, look a the wheel for grease splatter as it being slung off the axle and onto the bowl.

Thanks for the information.  I look forward to the NTSB's report.  Is this technology available to start applying to the car fleet, "They will either decide to utilize up-to-date, ultrasonic detectors, or the regulating 
authorities will require them to install and use the advanced technology detection."

Bob Wilcox
Charlottesville, VA
My Flickr Shots

Timken Inc. loves all the repeat boxcar bearing business for sure.

Yes, some of the first applications I heard of were about 15 years ago and I suspect the technology has probably be refined enough to allow mass application, (with the appropriate amount of dollars spent).
bobwilcox Wrote:
-------------------------------------------------------
> Thanks for the information.  I look forward to
> the NTSB's report.  Is this technology available
> to start applying to the car fleet, "They will
> either decide to utilize up-to-date, ultrasonic
> detectors, or the regulating 
> authorities will require them to install and use
> the advanced technology detection."

I mentioned that we demoed the SKF sonic system at Shasta Paper in the late nineties and now as to the comment about
refinement, the system was very sensitive to external noise not connected to the bearing condition. An abrasive saw in a
cutoff application 20 feet away drove it nuts! Over the years the frequency filtration and noise tuning has helped the
equipment greatly but as to the railroads, all you need is a few false indications for the equipment to be overlooked.

Out 



Edited 2 time(s). Last edit at 03/30/23 13:01 by callum_out.

I have a friend who spent 30+ years as a carman in a big hump yard.
One who actually walked the trains and bad ordered cars.
Did not do inspections from the shanty.
He only found 1 bad roller bearing in his career and that was
pointed out by a crew member who didn't like the noise it was making.

He says in his early days some roller bearings still had
grease fittings.  He was pumping grease into one on the
RIP and and old head yelled at him not to do it that way.
The old head pumped some grease on a finger and then wiped
it over the fitting to look like it had been greased. Probably why
they took the grease fitting off.

Haven't heard anyone talking about the requirement for a bearing inspection anytime a wheel is derailed. What used to be a "don't worry about it" has become a necessity.
CR

callum_out Wrote:
-------------------------------------------------------
> I mentioned that we demoed the SKF sonic system at
> Shasta Paper in the late nineties and now as to
> the comment about
> refinement, the system was very sensitive to
> external noise not connected to the bearing
> condition. An abrasive saw in a
> cutoff application 20 feet away drove it nuts!
> Over the years the frequency filtration and noise
> tuning has helped the
> equipment greatly but as to the railroads, all you
> need is a few false indications for the equipment
> to be overlooked.
>
> Out 

Right, my understanding is that *wayside* acoustic/vibrational detection of premature bearing failure needs all kinds of sophisticated signal processing to extract the high frequency squeal from all the (considerable) train noise and it's frequency harmonics. So lots of false positives which would be very expensive in both dollars and capacity and service quality.

That's why the Founder and CEO of Hum has been so active post East Palestine advocating for his wheelset mounted acoustic/vibrational sensors located close to the roller bearing. Only problem is that 8 of these babies are required per railcar times millions of railcars and maybe a telemetry system per railcar too if we don't believe the detection is proactive enough to look for a bad reading at the next terminal.