Situations are used to group a train with operating and environmental conditions.
Train objects are used to group a number of vehicle objects together.
Vehicle objects are used as containers for Wheelsets as well as Point, Line, Area and Box sources.
Wheelset model objects contain properties required for calculating rolling sound powers (requires rolling noise option).
Point sources are used for sound sources that can be approximated by a single small point.
Line sources are used for sound sources that can be approximated by a continuous line.
Area sources are used for sound sources that can be approximated by a flat rectangular area.
Box sources are used for sound sources that can be approximated by a 3-dimensional box, with different sound powers radiated from each face.
Track objects are used to group a number of parameters that relate to the rails, railpads, sleepers and ballast.
Environment objects contain settings that affect sound propagation, such as air and ground properties.
Barrier objects contain settings that affect the calculation of shielding and diffraction effects of barriers.
The Receivers model object is used as a container for all the Receivers in the situation.
Source grouping is used to summarise results by type, and also to enable certain types of sources to be on/off dependent on train speed.