In prototype practice, the length of a spiral is determined by speed and superelevation on the curve. The curve radius and applied super dictate a speed value for the curve. The length of the spiral is dictated by the rate of change of super (expressed in mm/sec or inches per sec), i.e. you are going from zero superelevation to, say 3" on the curve.
--- In [email protected], gftolhurst@... wrote: > > Dick, how long do you make your spiral easements? > > > Fred T > > > > > > -----Original Message----- > From: Bert Cutler <bertcutler@...> > To: Jeff Smith <[email protected]> > Sent: Sun, Feb 6, 2011 4:22 pm > Subject: RE: {S-Scale List} Re: Minimum radius question > > > > > > To: [email protected] > From: rnk2202@... > Date: Sun, 6 Feb 2011 11:06:44 -0800 > Subject: {S-Scale List} Re: Minimum radius question > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Ed et al -- > > > > The short answer is "maybe." 72-foot cars with body-mounted couplers will do > OK > > > on 30" curves as long as the nearest parallel track is at least 3-3/4 inches > > away, centerline to centerline. The problem comes where the curve meets the > > straight. You will need transition curves (spiral easements) offset by about > > 3/4 inches, easily achieved by using a three-foot .172 rail as a spline > against > > which to draw the easement centerline. No calculations required. > > > > Dick Karnes > > > > [Non-text portions of this message have been removed] > > > > > > > > > > > > > > > > > > > > [Non-text portions of this message have been removed] > > > > ------------------------------------ > > Yahoo! Groups Links > > > > > > > > [Non-text portions of this message have been removed] > ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/S-Scale/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/S-Scale/join (Yahoo! ID required) <*> To change settings via email: [email protected] [email protected] <*> To unsubscribe from this group, send an email to: [email protected] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
