To Measure a Rail Alignment Using Chord Length

Rail alignments have the option of being measured using the chord length of the curves instead of the true geometry length.

The length of alignments is typically measured along the geometry of the curves. Some agencies specify curves using a parameter called degree of curvature. These agencies often measure the length of a curve along the unit chord that is defined by that degree of curvature.

1. Click Alignment tabModify panelAlignment Properties drop-downAlignment Properties Find.
2. In the Alignment Properties dialog box, click the Chainage Control tab.
3. Under Chainage Information, select Measure Curves Along Chords.
   Note: The unit chord length and unit arc length typically are standard values that do not change within an agency. Because they are not frequently changed, the unit chord length and unit arc length values can be changed only on the Ambient Settings tab of the Drawing Settings dialog box, in the Degree of Curvature node.