The 'track modulus' is an index of measure of which of the following?

Concept:

Track Modulus:​

• Track foundation modulus, commonly referred to as track modulus, is defined as the supporting force per unit length of rail per unit deflection.
• Track modulus is thus a measure of the vertical stiffness of the track foundation and is related to the vertical deflection of the rail under a specified or known vertical wheel load.
• A related parameter, track stiffness, is a measure of the vertical stiffness of the whole track structure (effects of rail included).
• Track modulus is closely related to track performance as it is a measure of the structural state of the track.
• The effects of the fasteners, ties, ballast, sub-ballast, and subgrade are included in the track modulus.