The appraisal of riding quality based on the coefficient is done as follows;
(1) Riding Quality along Curves
Constant lateral acceleration due to unbalanced centrifugal acceleration may occur along curves. However, this is not a problem as long as speed restrictions imposed for reasons of safety are observed.
More of a problem is the degree of changes over time for cant and unbalanced acceleration.
This can be determined looking at the relationship between transition curve length and train speed.
(2) Geometrical Track Deformation and Train Vibration
Except in the case of self-excited vibration such as hunting movements where the problem lies with the train, train vibration is closely related to geometrical track deformation. In addition, this vibration increases in proportion to speed.
The relationship between geometric track deformation and train vibration can be calculated through a vibration analysis simulation using a dynamic model. Findings showed that there is good correlation between geometric track deformation over 5 m or 10 m spans and the train vibration of lower speed trains, but that for higher train speed, there was geometric track deformation with a longer wavelength has better correlation.
2.3 Track Deterioration
Excluding tracks with special structures, dynamically speaking, tracks are incomplete structures with the earth roadbed and ballast as a foundation. Track performance must be sustained through constantly restoring deterioration caused by trains through maintenance work. The main type of track deterioration is ballast sinking. Ballast sinking after tamping work generally progresses as shown in Fig. 3, and is a major cause of geometric track deformation. The speed at which track deterioration advances is closely related to the structural strength of the track and the damaging force of the train load.
