Single Track Rail Example - this is just one of many possible Section3D solutions and you may be able to come up with a better solution.

If you haven't installed the Section3D subassembly click on the button below to view How to Install Section3D Subassembly:



Rail-Single-Track-2010.dwg : Sample Civil 3D (2010) Dwg File used for this tutorial

Rail-Single-Track-Templates.zip : Section3D Full Template (fully reusable and modifiable) created in this tutorial

Rail-Double-Tracks-2011.zip : Another Sample Civil 3D (2011 format) Dwg demonstrating double tracks with two independent superelevations

The design profile of the top of rail is assumed always the lower side of the track, and the railroad superelevation starts from the beginning of the spiral and reaches the full superelevation at the beginning of the curve. This means the superelevation pivot point must switch from one side to another depending on the direction of the curve. To achieve this in Section3D, create a framework of points in a cases group (FRAMEWORK) where the first point (point 1) is the center of the track as shown below.



The next Cases group (DECISION) has three different cases (HIGH-LEFT, HIGH-RIGHT, DEFAULT). DEFAULT obviously represents the tangent railroad section with no superelevation. When S= values is assigned to the Civil 3D superelevation (which was be created in Civil 3D alignment) with the two marked name "LT" and "RT" as shown below, one of the three cases will be executed depending on the superelevation value at each station. Save this configuration as a template RAIL-SINGLE-DECISION.TPL. Note that this TPL file is Not a partial template since "Cases" group is created and therefore this template must be loaded and not inserted.

View the switching of Rail superelevation pivot point:



After clearing the screen, create a partial template SUBBALLAST-FRAME.TPL with some of the key points for the Subballast as shown below.



Load RAIL-SINGLE-DECISION.TPL (You must not insert since this is not a partial template due to the presence of "Cases" group) and insert SUBBALLAST-FRAME at Point 1 (Select Point 1 -> Right mouse click -> Insert Template -> Select SUBBALLAST-FRAME.TPL)



SUBBALLAST-FRAME.TPL point group is now merged with the existing code under the new Cases group name 1. By default, the group name is the point number when you insert the template from the Section3D Viewer, but you can rename the group name if you want.



Now you can create another "Cases" group (BALLAST) and add the Ballast points which interact with both the top of rail above and subballast below. Note that this station happens to be a superelevated station. There is also a minimum subballast shoulder width which must be respected on the high side of superelevation.



Mark all key points as shown below. You can label the marked points in the final plotted Civil 3D Cross-Sections.



Add another Cases group and add the TIE Points as shown below. Note that "L(ength)=,A(ngle)=,S(lope)=" key words are used to locate a point perpendicular to the superelevated slope. Note that the below TIE points do not appear perpendicular due to the vertical exaggeration.




Insert all ditches and fill slope(all partial templates) to both sides (Insertion points are 30 and 32)



You can also drag-and-drop one ditch case over others to set the order of execution. Click to View how to Drag-And-Drop one ditch case over others to set the priority of execution




You can now save this section as a full template. Map Point 1 to the target alignment and profile, and apply the full template to the entire station range as shown in the next three slides.



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The ability to superimpose the previous and next sections can be very useful. Not only you can see the transitions of all points/links clearly but also you can see that water will flow in the opposite direction of the alignment chaninage without looking at the ditch profile.



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TIE is displayed perpendicular to the rail superelevation when the vertical exaggeration set to 1.



In Section3D, every point is a variable and therefore you can create another railroad type by editing the slope of the subballast point. Only one two points (19 & 20) need to be edited with -2% slope since the other points (21 & 22) were coded with .X & .S constraints.



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If you do not know how to create the dynamic corrior using Section3D please refer to the Section3D 101 excercise.



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The extension of the subballast as a design constraint on the high side of superelevation is clearly visible on both sides.



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