A railroad track is a huge structure with different components. Among that ballast is the mainrnstructural component used to support the load from railroad ties and to facilitate drainage ofrnwater. The drainage efficiency of railway ballast is heavily influenced by aggregate gradations asrnwell as fouling material. It is critical to understand how the gradation of ballast aggregate andrnfouling material influences railway ballast drainage performance. The main goal of this researchrnis to evaluate the effect of different gradations of ballast aggregate and type of fouling material,rnand their combined effect on drainage performance of railway ballast on selected sites of AddisrnAbaba Light Rail Transit (AALRT). In the present study, the hydraulic conductivity of clean asrnwell as fouled ballast specimens are evaluated considering three different American RailwayrnEngineering Maintenance of Association (AREMA) gradation types and about 43 % of threerndifferent types of fouling materials. A sieve analysis is conducted to evaluate the gradation andrndegree of fouling on the track, and the percentage of fouling is also calculated. The hydraulicrnconductivity of clean and fouled ballast aggregate was then estimated using a constant headrnpermeability test. The Fouling Ratio approach was used to determine the level of fouling atrnKality Depot, Transition at Kality, and Gurd Shola. The experimental result of this studyrnrevealed that, the extent of fouling at transition is almost reaching to the category of moderatelyrnfouled ballast with the value of about 9 %. More uniformity of gradation of clean ballastrnAREMA No. 3 leads to higher values of hydraulic conductivity than AREMA No. 4 by aboutrn15% and AREMA No. 24 by about 19%. In addition, the clean ballast fouled by clay has shownrnreduction of hydraulic conductivity by about 4.5 %, 8.5 %, and 32.5 % of AREMA No. 24,rnAREMA No. 3 and, AREMA No. 4 respectively. It is necessary to create a solution whereby thernhighway meets the railway line along the transition.