Current American car trucks

[SCHHEAT]

Are trucks- bearings etc, water proof. Like if flooded by storm surge?

[mvlandsw]

They are sealed to keep rain and dirt out and lubrication in. I don't know how long this is effective if submerged.

[BaltACD]

mvlandsw

They are sealed to keep rain and dirt out and lubrication in. I don't know how long this is effective if submerged.

When submerged, each car must have the Car Dept. perform a 'Roller Bearing Inspection' before being OK'd for movement.  What that inspection consists of, I don't know.

[mudchicken]

The car is totally off the king(center)pin when they do it, the roller bearings are out of the cradle (journal). Liberally lubricated, nothing is allowed to seize up.

[SCHHEAT]

So are railroads pulling equip out of hurricane area, and do they pull engines or all inc cars at shippers facillites?

[BaltACD]

SCHHEAT

So are railroads pulling equip out of hurricane area, and do they pull engines or all inc cars at shippers facillites?

CSX New Orleans after Katrina in 2005

[Euclid]

How does water get in if oil can't get out?

[BaltACD]

Euclid

How does water get in if oil can't get out?

There is no such thing as a perfect seal.

[Overmod]

Euclid

How does water get in if oil can't get out?

Most modern roller bearings are grease-lubricated (M-942) in part to simplify the weather sealing.  However even slight depth of water exerts considerable hydrostatic pressure, and even small amounts of foreign matter or corrosive contaminants can cause substantial and rapidly-progressive damage in highly-loaded railroad bearings (there is more relative load than on, say, a watertight hub on a boat trailer).  I suspect that on freight trucks the wheelsets would be swapped out and the bearings run through preventive disassembly, solvent wash and re-greasing and seal/liner renewal 'just to be sure', the cost being less than recovering a road failure 'down the line'  On the other hand, with improvements in WILD, it may be more cost-effective to run them until signs of impending microdamage or wear become apparent, and swap the wheelsets out then and 'do' the bearings on a scheduled basis thereafter.

Remaining components on a three-piece truck are relatively simple to remove, clean and flush, and re-lubricate.  Situation is slightly more complex on a passenger truck depending on its construction, with the added complication of air cylinders and their associated equipment and various kinds of hydraulic dampers.  I am not sure how tolerant air suspension and its associated ride-height sensing is to immersion.

You didn't mention traction motors.  Those are a whole different story.

[Shadow the Cats owner]

Correct regardless of how much they try National Oil Seal and the other companies that make them still can not keep them from leaking over time and stop them from failing.  They wear out get damaged from debris and sooner or later they will leak.  

[ChuckCobleigh]

BaltACD

There is no such thing as a perfect seal.

Some orcas might disagree, but otherwise exactly correct.

[Euclid]

Are the bearings disassembled, inspected, cleaned, and re-lubricated at regular intervals even when they have not been submerged?  I would think that would be a necessary procedure.

[Deggesty]

ChuckCobleigh

 

 

BaltACD

There is no such thing as a perfect seal.

 

 

Some orcas might disagree, but otherwise exactly correct.

 

Are orcas fastidious, or do they simply eat what they can catch, and consider eavry seal perfect?

[Overmod]

Euclid

Are the bearings disassembled, inspected, cleaned, and re-lubricated at regular intervals even when they have not been submerged?  I would think that would be a necessary procedure.

Part of the point of modern bearing design and tribology is that the bearings have significant life as a 'package' -- sometimes several times the wear life of the wheels themselves.  While of course that doesn't mean an increase in actual miles before wheelsets 'wear out' (the bearings having to be disassembled when the wheels are taken off the axle) it does mean increased likelihood of the bearings remaining intact over the full service life of the wheelset, including when it is changed between trucks or checked after being tread-dressed after running with subcritical flatting.

Current policy is to use secondary analysis of impending failure, rather than 'preventative maintenance', to determine intermediate servicing of these bearings.  High-frequency microphones are the most common approach I have seen; there are distinctive vibration signatures that correspond (empirically) with a number of types of impending failure and when these reach a threshold value in amplitude or power spectrum they can be 'pulled' for service or rebuilding.

[Euclid]

Overmod

to determine intermediate servicing of these bearings. High-frequency microphones are the most common approach I have seen; there are distinctive vibration signatures that correspond (empirically) with a number of types of impending failure and when these reach a threshold value in amplitude or power spectrum they can be 'pulled' for service or rebuilding.

How do they set up those microphones?  Are they attached to the car trucks?  If so, is this just done for a test over a short period of time?  If that is the case, do they perform this test at specfic intervals?  Or is this microphone set up stationary at lineside and able to detect bearing problems as the cars pass?

 

 

[Paul_D_North_Jr]

Overmod

. . . Part of the point of modern bearing design and tribology is that the bearings have significant life as a 'package' -- sometimes several times the wear life of the wheels themselves.  While of course that doesn't mean an increase in actual miles before wheelsets 'wear out' (the bearings having to be disassembled when the wheels are taken off the axle) it does mean increased likelihood of the bearings remaining intact over the full service life of the wheelset, including when it is changed between trucks or checked after being tread-dressed after running with subcritical flatting. . . .[emphasis added]

John Kneiling used to point out that's why there was no point in having a bearing with a longer life than the wheelsets (however long that may be). 

Not advocating the point - I don't know enough about the subject - just pointing it out.

- PDN. 

[Overmod]

Euclid

Overmod

... High-frequency microphones are the most common approach I have seen; there are distinctive vibration signatures that correspond (empirically) with a number of types of impending failure and when these reach a threshold value in amplitude or power spectrum they can be 'pulled' for service or rebuilding.

How do they set up those microphones?  Are they attached to the car trucks?  If so, is this just done for a test over a short period of time?  If that is the case, do they perform this test at specfic intervals?  Or is this microphone set up stationary at lineside and able to detect bearing problems as the cars pass?

 

I believe the typical place to put them is in contact with the rail itself, as the high-frequency vibrations don't propagate well from structure to air.  If you look up designs of WILD detector you will get some reasonable idea of construction.  The idea at least as of a couple of years ago would be to look for vibration signatures as part of lineside detection, and associate this with a given axle position in a 'scanned' consist. 

 

It is comparatively difficult to 'test' this in a service facility since the cars there will not be loaded, and it will be difficult to spin wheels up to necessary speed with load on them.  Likewise putting vibration detectors in some seemingly obvious places like hump tracks will not produce signatures at high enough speed, although I think there are good enough other reasons to have them there.

 

It is possible to include this facility on a car, but the aggregate cost of implementing just this one function correctly would be wildly expensive for the benefits derived.  It is a sensible thing to implement as part of a more expensive system, in particular a 'mandated' setup of harness for ECP braking compatibility.  But that is a different discussion.

 

As an associated point, there has been an emphasis in recent years on regular 'dressing' of tread profile of wheelsets in service, particularly on unit coal trains.  I assume this is done by replacing the wheelsets on a given car quickly with 'reprofiled' ones, to keep the train in service, rather than using an underfloor lathe on the wheels 'as installed' in a consist, but either approach is possible.  Presumably the state of the associated bearings is checked at the time the wheels are reprofiled; if not, this would be comparatively easy to do, as would rebuilding any particular bearing 'under suspicion' at such a location.

[tree68]

Overmod

As an associated point, there has been an emphasis in recent years on regular 'dressing' of tread profile of wheelsets in service, particularly on unit coal trains.  I assume this is done by replacing the wheelsets on a given car quickly with 'reprofiled' ones, to keep the train in service, rather than using an underfloor lathe on the wheels 'as installed' in a consist, but either approach is possible.  Presumably the state of the associated bearings is checked at the time the wheels are reprofiled; if not, this would be comparatively easy to do, as would rebuilding any particular bearing 'under suspicion' at such a location.

I recall reading some time back that it had been discovered that if the wheels are turned to the same profile that they wear in to, their life is prolonged.  In the past, the practice had been a flat taper.  Apparently, that's not the optimum profile.

[SCHHEAT]

thanks for some excelent comments. my reason for asking was- are the railroads in florida pulling equipt out or do they just leave it and fix later???

[BaltACD]

SCHHEAT

thanks for some excelent comments. my reason for asking was- are the railroads in florida pulling equipt out or do they just leave it and fix later???

To pull it - you have to have somewhere that can hold it.

Today's Class 1's have 'right sized' their physical plants to just facilitate the business they currently service.  They have also 'right sized' their crew bases to be able to just service their current business.  

There are no crews to perform 'additional' work that clearing equipment out of entire geographical areas and also have no place to put that equipment.

Florida and New Orleans and the New York/New Jersey areas all have a different gographical and soil makeup and respond in different ways to the effects of hurricanes.  Florida is of a predominately sandy soil and water drains and percolates through that soil quickly and easily.  New Orleans, as a city, is build below sea level and only remains dry because of the various pumping stations that the area is quipped with along with the levees and dykes that act as the perimiter.  New York/New Jersey are built on hard rock - the so called New York Schist - the bed rock that anchors the foundations of the skyscrapers that New York is known for - water does not get absorbed into the soil easily or in great quantities.

[John Liebson]

This thread appears to be "orca-strated."

[cv_acr]

SCHHEAT

thanks for some excelent comments. my reason for asking was- are the railroads in florida pulling equipt out or do they just leave it and fix later???

There's no way any railroad has the crew and infrastructure capacity to empty out an entire state if they wanted to.