About Railway Design Standards

Using the Calculate Cant wizard, you can specify railway design standards, including formulas for equilibrium cant and maximum cant deficiency, and tables for applied cant, transition length and attainment method.

Railway design standards are stored in the drawing settings and the railway design criteria file. The appropriate standards are specified in the Calculate Cant wizard.

Drawing Settings

Default formulas for equilibrium cant and maximum allowable cant deficiency are stored in the drawing settings. The default formulas may be modified as needed before cant is calculated along the alignment.

Equilibrium Cant

The differential elevation (in mm or in.) at which the vertical wheel force is equal on both rails. You can modify the formula to incorporate mathematical operators and properties such as design speed, radius, and track width.

The default equilibrium cant formulas are:

  • Metric: 11.8*{Design Speed}^2/Radius
  • Imperial: 4.01*{Design Speed}^2/Radius

Maximum Allowable Cant Deficiency

Specifies the maximum allowable cant deficiency value to use in cant calculations. You can either enter a static value, or build an expression that incorporates mathematical operators and properties such as design speed, radius, and track width.

The default maximum allowable cant deficiency values are:

  • Metric: 100.00 mm
  • Imperial: 4.00 in.

Design Criteria File

The following railway design standards are contained in the design criteria file . You can customize the design criteria file to reflect your local standards using the Design Criteria Editor dialog box.

The XML-based design criteria file stores the standard tables and formulas that you can use to calculate cant rates and critical stations on an alignment.

Applied Cant Table

The applied cant table defines minimum radii for rail type and design speed.

Transition Length Table

The transition length table specifies values you can use in the Attainment Method formulas. You can use the table to calculate the distances between the cant critical stations as a function of curve radius and design speed.

Attainment Method

Specifies how cant is applied, and the method that is used to calculate cant critical stations in different situations. Each defined method specifies the variables used to calculate the distances between the critical stations.