Talk:Hunting oscillation

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The Japanese article on this subject appears to include additional information not covered here. Unfortunately, I can't speak a word of Japanese. Could some kind translator out there please have a go at translating the Japanese article. If you are a native Japanese speaker, with limited grasp of English, please have a go, I'm sure we can sort out the grammar and style issues once we have got a first iteration to work with. Gordon Vigurs 09:45, 27 August 2006 (UTC)

Swaying?
Sorry, always nit-picking, but to me swaying is what a drunk does rotating vertically pivoting on his feet (rolling and pitching?), whereas hunting is a horiontal oscillation around a vertical axis. I surmise that the image may originally have been one of a dog following a scent sniffing right and left. This is more like the motion of a railway vehicle described. In aircraft flight as I understand it, you have three basic oscillations to contend with pitching, rolling and yawing (the equivalent of hunting?).--John of Paris 10:02, 3 July 2007 (UTC)


 * The swaying motion refers to the qualitative manifestation of hunting in complete railway vehicles - a mix of lateral translational motion and yaw. The analysis here is restricted to wheelset hunting, which is about the only level amenable to analystical solution. The real situation is much more complex.  If you can imagine the wheels sets and bogies at either end of the actual vehicle oscillating from side to side, not necessarily in synchronisation, you will get the picture. Gordon Vigurs 07:39, 9 July 2007 (UTC)

Proposed merger
Fine, provided that the detailed railway engineering diagrams and calcuations go at the bottom - "hunting" is used in a wide range of contexts. Philcha (talk) 10:43, 20 April 2008 (UTC)
 * No It is an article specific to railway engineering, where the wheels are fixed on the axle, and should be tied into other such articles, particularly wheelset (rail transport) and Bogie Perhaps it should be renamed to reflect this. Chevin (talk) 11:07, 22 January 2009 (UTC)
 * Except hunting oscillations occur in other things, such as motorbikes etc.
 * The page should be moved to "Hunting oscillations (rail)" or generalised.77.86.67.245 (talk) 21:17, 11 April 2009 (UTC)
 * Generalized. -AndrewDressel (talk) 13:48, 24 June 2011 (UTC)

It's all greek to me!
I just tried to understand this, but it's fairly heavy in terms of mathematics. I appreciate that the authors have spent a lot of time trying to give an accurate, full, account of what causes hunting oscillation, but even the summary ("The classical Hunting oscillation is a swaying motion of a railway vehicle caused by the coning action on which the directional stability of an adhesion railway depends") doesn't really convey much to the layman beyond the notion that a vehicle might sway (and it doesn't help that "Coning" in the above links to the definition of the word "Cone".)

A couple of things might help here. Before the heavy maths part of the article, some kind of brief layman's language description of how the wheelsets sway (that is "In Hunting oscillation, a wheelset - two flanged rail riding wheels attached to a common axle - moves left and right, relative to the track, progressively more violently" - I have no idea whether that wording is right! But you get the idea of what kind of language I'm looking for) and broadly what causes it ("The cone-like nature of the wheels themselves means that the wheelset has no fixed, horizontal, relationship to the rails - that is, if the wheels are slightly to the left, the wide side of the left wheel and thin side of the right will be in contact with the rail, causing the axle to be higher on the left than on the right. The changed center of gravity causes the wheels to slip back into the opposite direction as the train moves.")

Again, no idea if what I just said is right because I don't understand the article, but it's an example of the kind of language that might be easier to understand.

Even better would be more diagrams, or even a short animation.

Does this make sense? Is this even possible? --66.149.58.8 (talk) 18:32, 18 December 2009 (UTC)


 * The points you make are valid. However, it doesn't help matters if some genius sees fit to change the cross reference for 'coning' from 'adhesion railway' where it might be explained, to 'cone', which is totally irrelevant.Gordon Vigurs (talk) 08:41, 24 June 2011 (UTC)

Name origin
It's not clear to me whether the term Hunting oscillation is named for a person named Hunting, or if "it is a behavioral description". This could easily be cleared up in the lead by someone knowelgeable. 70.247.164.231 (talk) 03:55, 28 August 2010 (UTC)
 * Done with reference from OED. -AndrewDressel (talk) 13:47, 24 June 2011 (UTC)

Hunting is a behavioral description. The term hunting comes from the responce of train tires to rails. It is intended that the tire treads steer the train on rails. There are inaccuracies in all aspects. Rail path has design tolorances and path is subject to changes caused by temperature. Train tires are trued to a tolorance that effects responce to rail path. Also, tires are assembled on trucks to tolorances. Rubber suspension elements are installed in sets to give equal load pressure on four treads. At walking speeds there is no harmonic hunting. Combined out of tolorance inputs can result in harmonic hunting. (I worked on electric trains from May 1986 through January 2009. Accurate tire truing demonstrated benefits in wear and ride quality.  TriMet, Portland, Oregon -- verifiable)Ruby3182 (talk) 03:25, 20 September 2011 (UTC)

Usually unwanted?
Hello together!

The introduction says: "Hunting oscillation is a self-oscillation, usually unwanted, about an equilibrium." However, most of the article describes railway wheelsets, and railways wheelsets need that kind of oscillation: To move around a curve, the revolutions of the left and the right wheel have to be slightly different, and that is realised by a relocation as described here. So it is not an unwanted phenomenon, but a necessary one?

Greetings from Germany, SimonFromGermany (talk) 18:48, 23 September 2017 (UTC)


 * It is one thing for a wheelset to drift to the outside of a curve and then recenter upon exiting the curve, and entirely another thing for a wheelset to rapidly oscillate back and forth on straight track to the point of causing derailment or damaging the track. This article is about the latter. -AndrewDressel (talk) 21:09, 23 September 2017 (UTC)