DC Railway Traction Power Supply System (TPPS) has been and is still widely used worldrnover for train propulsion especially in the urban areas and inter- urban regions. With thernevolution of electronic traction control technology giving compact size and reduced weightrnof chopper and inverter drives, DC railway traction has become advantageous especiallyrnwhere we have minimal provision for electrical clearances. Currently, the standard DCrntraction voltages are 750V, 1500V and 3000V which require less electrical clearancerncompared to AC Railway Traction Power Supply System catenary. rnThe basic function of an electrical power system is to meet its customerâ€™s expectationsrnwhile maintaining the acceptable levels of quality and continuity of supplies. Thernreliability level of DC Railway Traction Power Supply System is a major contributor tornthe quality of service provided by a railway authority, thus there is a link betweenrnreliability and quality of service. While most of the contingency situations may bernpredicted and counteracted on the design stage, only the real-life experience is the ultimaterntest for reliability. Reliability is regarded by many researchers as the science of failuresrnand the work of a reliability engineer is to assess the trend of failure data and determinernthe rate of occurrence of failures as accurately as possible.rnrnThis research, therefore, addresses the reliability question at AALRT through collectionrnand analysis of power interruption data. This data is used to compute performancernindicators or indices such as; Basic Reliability Indices (failure rate, MTBF, MTTR andrnavailability), Customer Orientation Indices (SAIFI, SAIDI, CAIDI, ASAI and ASUI) andrnEnergy and Cost Indices (EENS, AENS, ECOST and IEAR). From the period of studyrn(2016, 2017 and 2018), this research finds out that the System Average Interruption IndexrnSAIFI) is 7.47 interruptions per customer and System Average Interruption Duration Indexrn(SAIDI) of 58.17 hours per customer. These indices are benchmarked with the those ofrnother countries. A model of the AALRT TPSS is developed and three cases of potentialrnreliability improvement alternatives are simulated using an ETAP software. Thesernimprovements gave an overall reduction in EENS of 80.869 MWhr/yr. A cost-benefitrnanalysis of the reliability improvement alternatives is also done to justify the investment.