About Multiple Stationing and Station Equations

A station equation is a specific point on an alignment used to start a new stationing from a given position on the alignment. A horizontal alignment can manage more than one stationing, each being specific to an alignment section. Like characteristic or transition points, station equations are seen in 2DL tables and are reported in the exported xml file.

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Station Equations and Stationing

To start a new stationing on a horizontal alignment, you must create a specific point on the alignment. This point is called station equation. It is coincident with the alignment, fixed in position and is initially defined with reference to the stationing to be split. The new stationing is located before or after the station equation depending on the option selected.

Station Equation

Station equations are accessible when editing the horizontal alignment and are characterized by:

Characteristics Description
Label Text displayed on the station of a given stationing.
Ahead station Position of the start point expressed in the reference of the current stationing. For example, it can be 0+00.
Back station Position of the start point expressed in the reference of the previous stationing. For example, it can be P2+01.
Color Both the color of the point and the color of station names.

Stationing

The main stationing details are stored in the horizontal alignment:

  • Label: this is the text displays on a station of a given stationing
  • Start station: this is the position of the start point expressed in the reference of the main stationing. For example, it can be 0+00.

The color of station names for the main stationing can be changed through the color of the alignment start point.

All parameters are customizable in Data Setup.

Use Cases

This section provides you with the two main use cases requiring station equations and new stationing.

Anomaly Detected Requiring Two Station Equations

During production phase an anomaly is detected on field and requires a design change. For example, the soil quality is too poor to establish a bridge pier and thus requires to locally deviate the alignment.

To solve this case, you must create two station equations, one behind the anomaly and one ahead the anomaly. Both stationing sections - behind and before the anomaly- remain unchanged. So, all the assets positioned relatively to those stations are not impacted by the design change. Between the two station equations, a station is created with a different label.

On above picture, we can see 3 stationing:

  • The first starts from the alignment start point (P0+00) and stops at the first station equation (P2+00 or K0+00). The first stationing is also named the main stationing since its details are stored directly on the alignment and not on a station equation
  • The second starts from the first station equation (K0+00) and stops at the second station equation (K1+50 or P2+85)
  • The third starts from the second station equation (P2+85) and goes till the end

Important:
  • Stationing labels must be different between two successive stationings so there is no possible confusion on station names.
  • Stationing labels can be equivalent on non-successive stationings so station names from both sides of a design change remain unchanged.
  • Stationing sharing the same label should never define stations having the same coordinates.

Anomaly Detected Requiring a Station Equation

During production phase an anomaly is detected and requires a design change. The production was only started on a side of the anomaly.

To solve this case, the user needs to introduce a single station equation, either behind or ahead depending on the side already in production he has to freeze. For example if he has to freeze the stationing behind the anomaly:

Or if he has to freeze it ahead the anomaly:

Important: Sometimes the introduction of a new stationing may lead to change the label of the main stationing.