About Rotation Modes on a Road/Railway Surface

Rotation modes are available at alignment creation and edition.

When you hover over a Rotation mode in the Road/Railway Surface dialog box, a tooltip is displayed.

This page discusses:

Tooltip legend
Rotation modes for a crown traveled way
Rotation modes for a planar traveled way

Tooltip legend

The table below shows the legend of the tooltips' images.

In the Horizontal Alignment Initialization and Alignment Specifications dialog boxes, you can choose a traveled way type as described below, and a rotation mode:

Planar: the shape of the road/railway surface provides a straight plane, with one slope.
Crown: the shape of the road/railway surface provides two sloped planes forming a crown.


	Rotation in both directions, left and right.
	Rotation either in the left direction or in the right direction.
	Right or left turn.
	Forward
	Alignment.
	Left side of the traveled way.
	Extremities of the central median.
	Right side of the raveled way.

Rotation modes for a crown traveled way

The table below gives an overview over the crowned profile and the behavior of the Road rotation modes, explaining the images of the corresponding tooltips.


Section in Tangent	Right	Left
	Full Superelevated Section
Centerline
The traveled way revolves about the centerline (alignment) in both directions and depends on the turn direction.
Inner edge
The second image depicts the Inner edge rotation mode when turning right, with a rotation along the right side of the alignment. The third image depicts the Inner edge rotation mode when turning left with a rotation along the left side of the alignment.
Outer edge
The second image depicts the Outer edge rotation mode when turning right, with a rotation along the left side of the alignment. The third image depicts the Outer edge rotation mode when turning left, with a rotation along the right side of the alignment.
Right Side
The second image depicts the Right rotation mode when turning right, with a rotation along the right side of the alignment. The third image depicts the Right rotation mode when turning left with a rotation along the right side of the alignment.
Left Side
The second image depicts the Left rotation mode when turning right, with a rotation along the left side of the alignment. The third image depicts the Left rotation mode when turning left, with a rotation along the left side of the alignment.
Center of central median
The first image depicts the surface profile at the beginning of a turn in any direction. Rotation starts on the edges of the central median. The second image depicts the surface profile while turning in the right direction. Rotation occurs on the center of central median axis. The left and right sides of the profile no longer rotate and follow the central median rotation. The third image depicts the surface profile while turning in the left direction. The rotation process is the same as the one in the second image.
Edge of central median
The first image depicts the surface profile at the beginning of a turn in any direction. Rotation starts on the edges of the central median. The second image depicts the surface profile while turning in the right direction. Rotation occurs along the edges of central median. The third image depicts the surface profile while turning in the left direction. The rotation process is the same as the one of the second image.

Rotation modes for a planar traveled way

The table below gives an overview over the planar profile and the behavior of the Road and Railway rotation modes, explaining the images of the corresponding tooltips.


Section in Tangent	Right	Left
	Full Superelevated Section
Centerline
The traveled way revolves about the centerline (alignment) in both directions and depends on the turn direction.
Inner edge or Inner rail
The first image depicts the surface profile at the beginning of a turn in any direction. Rotation can start on the left side or right side of the alignment, and depends on the turn direction. The second image depicts the Inner edge or Inner rail rotation mode when turning right, with a rotation along the right side of the alignment. The third image depicts the Inner edge or Inner rail rotation mode when turning left with a rotation along the left side of the alignment.
Outer Edge or Outer Rail
The first image depicts the surface profile at the beginning of a turn in any direction. Rotation can start on the left side or right side of the alignment, and depends on the turn direction. The second image depicts the Outer edge or Outer rail rotation mode when turning right, with a rotation along the right side of the alignment. The third image depicts the Outer edge or Outer rail rotation mode when turning left with a rotation along the left side of the alignment.
Left Side
The first image depicts the surface profile at the beginning of a turn in any direction. Rotation can start on the left side of the alignment only. The second image depicts the Left rotation mode when turning right, with a rotation along the left side of the alignment. The third image depicts the Left rotation mode when turning left, with a rotation along the left side of the alignment.
Right Side
The first image depicts the surface profile at the beginning of a turn in any direction. Rotation can start only on the right side of the alignment. The second image depicts the Right rotation mode when turning right, with a rotation along the right side of the alignment. The third image depicts the Right rotation mode when turning left with a rotation along the right side of the alignment.