Easements!

Hi:

Although the theory behind easements is complicated, for practical purposes, installation is quite simple using a metal rod (rail) for the bent stick method. Offsets can be calculated from the equation in the NMRA sheets.

Since I use a 36" minimum radius for mainline, you might find some useful information and examples on the first site below.

Hope this helps.

Thank you,

Budb

Author of:

MODELRAILROAD TECHNICAL INFORMATION

MR TECHNICAL HELP GROUP

If you have a copy of Armstrong's "Track Planning for Realistic Operation" the general formula is in there.

-dave

And Mallery's "Trackwork Handbook" has a template for up to 48" radii, IIRC.

If that's your response to what you found on the Internet, I hope you didn't see my spreadsheet!

Andrew=A0Jeanes wrote: Argh! I'm trying to figure out the correct dimensions for a spiral easement into a 36" radius curve, and the online resources I've found so far are just giving me math anxiety.

---------------------------------------------------- Perhaps these sites will be helpful:

Bill Bill's Railroad Empire N Scale Model Railroad:

Check out this easment printing software.

snipped-for-privacy@tracer.consecol.org (Andrew Jeanes) wrote in news:c5dc62$ga$1 @driftwood.ccs.carleton.ca:

============

The book "Track Planning for Realistic Operation", by John Armstrong,

On Mon, 12 Apr 2004 06:15:30 UTC, snipped-for-privacy@tracer.consecol.org (Andrew Jeanes) wrote: 2000

For a quick and dirty setting offset the curve center by 1/2" (36-1/2 inches from tangent). Measure 12" either side of the start of the curve (PC). Tie your spline to the tangent up to 12" before PC and tie your spline to the 36" curve beyond 12" past the PC. I use several nails to make sure the spline follows the tangent and the curve. Accurate enough for what you want.

Hello Andrew;

I don't know if you have been able to do your curve with the suggestions you have had on your inquiry, however; if you can give me an approximate length you would like, I can quickly draw / plot an easement on AutoCAD at my office and send you the drawing.

I've done some long curves for friends - 36" easement into a 48" curve and just cut out / pasted the print on the subbase. It also acts as a layout template and I offset the centreline to the outside of the ties so it's as simple as putting the track inside the lines. One time we did an entire yard this way.

All I'd need is your mail address....

Ian Mathers Great Northern Sand & Gravel Company Yellowknife, NT

just cut out / pasted the print on the subbase<

Ian, Didn't you really mean a 48" easement into a 36" curve ?

Perhaps he's easing away from using set track?

No, I meant a 36" long spiral into a 48" radius curve. Looked very nice.

Ian

Ok. Interesting, not wanting to start an argument but I always thought the definition of easement was a large radius curve going to a smaller radius curve. Could be I have never understood the definition.

It is. Normally the lenght of the easement is given.

Perhaps a drawing could enlighten you. Have a look at

Would going from a small radius to a larger radius be a "diseasement"? ;-)

I think the intent was a _36" long_ transition from straight to 48" radius curve.

Regards, Greg.P.

If you look at it the other way, it is a 48" radius curve leading into a 36" helix.

The length of the spiral is not the radius - it's the distance travelled during the transition from the tangent to the final curve. The spiral begins at an infinite radius (tangent) and as it develops, the radius diminishes until it matches the simple curve in the middle. At the other end, as you come out of the simple curve into the spiral the same thing happens in reverse until you are on tangent again. So the curve is 3 parts.....spiral in....simple curve....spiral out.

About a year ago, I did some AutoCAD renderings of a curve. They are at :

Ian

Thanks Erik!

Strangly enough, I was going thru my old RR information this afternoon and came across your origional easement posting from Sat, 23 October 1999 05:11 PM EDT. In that post you gave the formula for Danish RR easements. The graphics you have posted here are a great help in understanding how to calculate the offset.

Tusen Tok,

Ed