as trains runs hour after hour, generats huge heat, though no cooling/greeshing etc. are normaly used. does wheel rotate on ball-bearing or something better.....
2007-02-13 07:36:02 · 7 answers · asked by Anonymous in Cars & Transportation ➔ Rail
Some good answers so far....
The freight car bearings are tapered roller bearings. Google timken, and go to their web site.
The tapered roller bearings are used because they can take axial loads, which ball bearings cannot tolerate very well.
They are like the ones on your car, but for different reasons. The inner and outer bearings on the fron of your car both install with the bigger end toward the inside. This is because you can press on the inner race and rollers on the axle, and the outer race on the hub, then slide the hub on the car and tourque down the nut.
The bearings in this configuration can take axial loads toward the center of the car, but not outward. This is not a problem, because axial loads are small.
This is done solely for installation convenience. With ball bearings you couldn't do this.
On railroad freight car bearings, the narrow portions face each other so as to take axial loads either way. They are pressed on the axle.
Most locomotive (diesel) and passenger cars used regular roller bearings rather than tapered. Axial loads were much less on passenger, and thrust bearings were used on diesels.
Now about 1980 however, the technology has been improved such that most locomotives now have tapered roller bearings. You can tell, because the end cap rotates.
Most passenger cars are now buillt with tapered roller bearings.
However, if you look at Amfleet cars, you'll notice all you see is wheel. The bearings are pressed on the axle before the wheels are pressed on. This has the advantage, the wheels can be changed without disturbing the bearing. The bearings last much longer than the wheels.
2007-02-13 13:51:32 · answer #1 · answered by mt_hopper 3 · 0⤊ 0⤋
More often than not they are riding on Timken roller bearings.
Though hundreds of times more efficient than the old journal boxes, they still overheat from time to time with the age old "hot box" as a result. Today, automated trackside "detectors" scan passing trains for overheated journals and, when one is detected, transmits a radio message informing the crew of the nature of the problem, the indicated axel and the side it is on. It is then the responsibility of the crew to stop the train and perform the required inspection. (Note: There is a preferred method of stopping a train with a suspected hot box. Hoghead's Highball on my 360 blog will be going into this soon.)
A "templstick" is used when in doubt as to the temperature of the journal. This is a "crayon" like object which will melt over a certain temperature. Apply the temple stick to the area in question, and, if it melts, the journal is in distress and the car will be "set out" at the first place available and not moved until repairs are conducted by the car department.
If temperature becomes too high, the bearings will melt and the axle drop, then you wind up with several cars sideways or on top of each other.
Yet another good reason to give a train a wide berth and stay off the right of way.
2007-02-13 07:55:30 · answer #2 · answered by Samurai Hoghead 7 · 1⤊ 0⤋
They're tapered roller bearings packed and sealed with grease. Your car's front axle has the same thing. Except on the railroad, a roller is as big as your pinky :)
Bearings are designed to run cool. They shouldn't be getting hot, unless they are failing.
In the old old days, bearings were a bronze slug that sat on top of a steel axle, and underneath the axle was a bunch of rags soaked in oil, that wicked oil to the bottom of the axle, which carried it to the bearing. When one of those bearings went bad, it would heat up and the rags and oil would catch fire and it would make stink and smoke for miles! That's part of why they had cabooses, to watch for that. They also have "hot box detectors", trackside scanners that look for hot axles, which means a failing bearing. That type of bearing was phased out and was completely gone by the 1980s.
Nowadays, bearings are much more reliable, but when they do fail, it's less obvious, and they go from "OK" to "catastrophic failure" much faster. This makes them harder to detect.
2007-02-13 08:57:27 · answer #3 · answered by Wolf Harper 6 · 0⤊ 0⤋
All are good answers. As to who makes them and all of those kinds of things that would be up to the car man to know that. When axles get hot and set off the Wayside Detector it is possible that the crew did not get a good air test, there is a leak somewhere in the system that has occured after the air test, and I believe the biggest thin that I have seen while working for the railroad is that a Hand Brake has been left applied. Or even sticking brakes.
2007-02-13 16:25:26 · answer #4 · answered by justinaplin 2 · 0⤊ 0⤋
I'm pretty sure your friendly, smiling Snap-On guy has some "Special Snap-On Grease" he would be glad to sell you but I have worked with and been around roll-away tool boxes, including Snap-On, all my life and if when you cleaned those slide bearings there was the tiniest bit of grit left no grease will make them smooth. I don't mean to insult you but the heavy, sticky grease that was there originally was for longevity of the grease, not for smooth operation of the bearings. If the bearings are clean and pit free even a light grease will work smooth for a short time, until it is forced out of the bearing by the load.
2016-03-29 05:10:19 · answer #5 · answered by Anonymous · 0⤊ 0⤋
A set of large tapered roller bearings.
2007-02-13 07:56:44 · answer #6 · answered by yes_its_me 7 · 0⤊ 0⤋
big *** roller bearings similar to what a car has .
2007-02-15 09:57:18 · answer #7 · answered by accomacgeo 4 · 0⤊ 0⤋