Need to create easements on the Great Northern

[Michael Boyle]

Greetings,
I have been trying to use the easement tool for my mainline curves and cannot detect any change in curve position. For example: If I draw a 50 degree 38" radius with straight stretches at both ends and compare it with a 20 degree 38" radius curve joined to two 15 degree (38" radius) easements, the two drawing seem to exactly overlap, even at high magnification there is only the very slightest difference. Does this suggest that these are not really working easements? Am I doing something wrong?
Any help would be greatly appreciated.
Thanks,
Michael

[Tom Springer]

Can you post your AnyRail file(s)? Many on here, other than me, are good at easements.

[Michael Boyle]

I would like to create easements from the three straight sections on the left going into the curves. The curves are (from inside to out) 36", 38", and 40". Any help would be greatly appreciated.
Thanks,
Michael

[Michael Boyle]

Hello Tom,
Thanks for being willing to help. Attached is a jpeg of a segment of my layout. I would like to have easements between the straight stretches on the left and the adjoining curves. The radii are 36, 38, & 40". (The full layout is also attached.)
Any suggestions would be greatly appreciated.
Thank you,
Michael

[David]

You're doing nothing wrong! But using the values you give, there's just not that much difference between a curve and an easement.
If you create two easements spanning 25 degrees, radius 38", and connect these, you'll see a much larger difference.

The general idea is that an easement approximates a spiral, meaning that the radius goes from infinite (straight line) to the radius you enter, where the radius decreases gradually along the stretch.

There's been plenty of discussion on the math here:
https://www.anyrail.com/forum_en/index.php/topic,2616.0.html

Anyway, in general, use small angles to make them use less space, and larger angles to make them spread out more.

[Tom Springer]

Michael,

Following what David has said, attached is an example using your layout.  I reduced your layout to the upper left corner section where I think you were looking for an easement approach.  Your space for an easement is too small to allow AR to create a true easement; hopefully the attached example will show this.  And provide one means to create an "easement" for this track.

The straight sections in white coloring is where I cut the tracks to remove the other parts of the layout to focus just on the corner section for this example, in particular the curved outermost track segment.

There are 4 layers in this example.

Layer 01: original track  is the original track you provided.  I marked the points (1 and 2) where I think you want an easement to occur.

Enable layer 02: with normal easement  and you will see what an easement of 45 degrees and 36inch radius done with the AR "easement flex" function would look like.  You can see how broad of a curvature this track would be.  Clearly there isn't sufficient space for a true easement in this area, at least not one using the 45 degree 36inch radius approach.

I think the issue for you is how to create "by hand", effectively, an easement (or something close to one), from point 1 to point 2.

Enabling layer 03: new artificial easement  and hiding layers 01 and 02, you can see what something like an easement, created by building the parts individually, could look like.  The 2 yellow track segments were created by the AR "easement flex" facility, using a 10 degree angle and a 36in radius, resulting in these "end segments" being a logical easement for each end of the track.  The track segment in purple was created, first, as a 70 degree 36inch radius flex track, then attaching the lower end of this purple track to the yellow easement track on the left, and finally, attaching the upper end point for this purple track to the end of the upper yellow easement track. The yellow-purple-yellow track segment now functions as an "easement" even though it doesn't meet the requirements of a proper easement.

You can see how this yellow-purple-yellow "easement" track segment compares to the original curved 36inch radius track segment by enabling layer 04:original curve overlay to map the original curved track, now colored pink, to this "artificial" easement track.

I hope this helps in a small way.

[Michael Boyle]

Tom and David,
Thank you. Your help was perfect. I have now added the easements, using 25 degrees where possible.
-Michael Boyle