Analysis of Track Geometry Quality Index for Addis Ababa Light Rail Transit

No Thumbnail Available



Journal Title

Journal ISSN

Volume Title


Addis Ababa University


The use and need of railway transportation system is increasing due to different reasons; it uses less energy, environmental friendly, high speed and huge capacity. The increment of axle loads leads to the design of high quality track structure materials in order to enhance the life span of the line. Even though, the track structure is designed for a longer design period, its performance is reduced from time to time. For this reason the status of the structure should be assessed periodically. The aim of this research is to analyze the track geometry quality index of Addis Ababa Light Rail Transit (AALRT).In order to conduct this research deterministic statistical method was used. The track quality index model was developed using multiple linear regression analysis. In this method the average track irregularities of cross level, alignment, twist and gauge parameters were used as an independent variable whereas the track quality index was used as a dependent variable or response. The result showed that most of the common track irregularities in AALRT were cross level and gauge irregularities which cover 60 % and 32 % of the total irregularity percentage respectively. The research found that the maximum value of track quality index is 9.51 mm which was 63.4 % of the threshold limit (15mm). The rate of change of track quality indices were calculated for twelve segments. The maximum rate of change of track quality indices (track deterioration rates) was 7.54 mm/yr which was found in curves with embankment (ballasted track). Finally, the adequacy of the developed track quality index model was checked based on the assumptions of multiple linear regression and also it is validated using variance inflation factor (VIF).The VIF values of the four independent variables; i.e., cross level, alignment, twist and gauge irregularities are 1.12, 1.11, 1.03 and 1.08 respectively were less than 5. As a result, the model is valid and can be used in the future to show the status of the track and manage track maintenance activities.



Track Quality Index, Maintenance, Statistical Model, Deterministic Method