Figure 2
The diagram illustrates the components involved in the gauge calculation of railway tracks. It features two parallel rails connected by various labeled elements. The labels include Alignment, Cross level, Twist, Longitudinal level, and Track gauge. Alignment is indicated by red arrows showing the horizontal positioning of the tracks. Cross level, represented by purple arrows, shows the lateral tilt between the tracks. Twist, marked by green arrows, indicates the rotational movement between the tracks. Longitudinal level, shown by blue arrows, represents the vertical alignment of the tracks. Track gauge, depicted by an orange arrow, measures the distance between the inner sides of the two rails. The diagram visually explains how these components interact to define the three-dimensional geometry of the railway track.Schematic diagram of gauge calculation. Source: Figure courtesy of Han et al. (2023)