Figure 2
The diagram illustrates a track longitudinal irregularity with a rectangular block labeled 'Advance' pointing right. Below the block, a circular object is connected to a spring and a rectangular component, indicating a mechanical system. The circular object interacts with a wavy blue line representing the track surface, with a vertical measurement of plus 3 millimeters indicated.Schematic diagram of track longitudinal irregularity. Source(s): Author's own work