steam loco question

[nw-mailing-list at nwhs.org]

I won't repeat the answers given so far, which are all correct  and well 
explained, but there's two more factors, as it's been explained to me  over the 
years (I'm an old electron pusher, so I take these things on faith):  were not 
most steam locomotives built with a certain amount of lateral motion  allowed 
in the journal boxes?  Even thought the frame and bearings would  hold the 
driving axles parallel, the ability to shift laterally slightly would  also help.  
Secondly, while in the ideal case the conicity of the wheel  sets would 
eliminate or minimize flange contact, in the real world there is  flange contact.  
As long as the angle of attack of the flange is small and  the shape of the 
flange is correct, the wheel will not climb, but rather  the flange will keep 
the wheel in place.  The geometry of the flange  and rail head result in a 
measure called the "L/V" ratio, the ratio of the  lateral force (which tends to 
cause flange climb) to the vertical force (which  keeps the wheel in place).  I 
have read what a desired limit of the L/V  ratio is but I confess I didn't 
commit it to memory. 
 
Dave Phelps
 
In a message dated 6/27/2006 9:16:08 P.M. Eastern Daylight Time,  
nw-mailing-list at nwhs.org writes:

The tires and wheels on locomotives, as well as rolling stock, are shaped  in 
such a way that as the wheel enters a curve, the outside wheel raises up on  
the wheel flange, and the inside wheel lowers closer to the rail head, thus  
creating a cone effect, with the outside wheel on a slightly larger diameter  
than the inside wheel.  At least, that's the way a retired railroader  
explained it to me.  I hope it makes sense.  He drew me a picture to  make it more 
plain.
 
Ben Blevins

nw-mailing-list at nwhs.org wrote:

A  steam locomotive enters a curve with drivers on both sides eating up the  
same amount of rail,--why does the drivers on the shorter rail not climb out  
??  
  
____________________________________
 Do you Yahoo!?
Get on board. _You're  invited_ 
(http://us.rd.yahoo.com/evt=40791/*http://advision.webevents.yahoo.com/handraisers)  to try the new Yahoo! Mail  
Beta.________________________________________
NW-Mailing-List at nwhs.org
To  change your subscription go  to
http://list.nwhs.org/mailman/options/nw-mailing-list


 
____________________________________
Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls. _Great  rates 
starting at  1¢/min.

________________________________________
NW-Mailing-List at nwhs.org
To  change your subscription go  to
http://list.nwhs.org/mailman/options/nw-mailing-list_ 
(http://us.rd.yahoo.com/mail_us/taglines/postman7/*http://us.rd.yahoo.com/evt=39666/*http://messenger.
yahoo.com) 


 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://six.pairlist.net/pipermail/nw-mailing-list/attachments/20060627/17701b4e/attachment-0001.html