AbstractThe subway is one of the most important public infrastructure systems able to accommodate huge numbers of passengers daily and across the world. Hence, governments are always obliged to provide and secure a large amount of funds to maintain the required levels of performance. Nevertheless, the majority of current operating subway networks have faced significant deterioration in their provided services. This deterioration is not just confined to the unavailability of sufficient funds from governments, but also to the absence of comprehensive maintenance plans and a lack of documentation of past maintenance. In the same manner, governments are facing problems securing sufficient funds to maintain the operational efficiency of subway networks. This research presents a model for the condition assessment and budget allocation optimization of subway operating systems. The model incorporates technical maintenance information and maintenance progress metrics for each subway component defined on a building information modeling (BIM) model. The output of this model is utilized by BIM as an interoperable platform to regulate maintenance action documentation and track the actual maintenance progress status in subways. The selected operating systems were identified based on their contribution to the level of service. These systems include overhead catenary, communications, rolling stock, railway tracks, ticketing, lighting & power supply rectifier stations, and centralized control. A BIM-based model was developed to integrate the optimized maintenance plans with the modeled subway components and to compare the actual maintenance practices with optimized planned actions. Cairo Metro line 1 was adopted as a case study to showcase the main characteristics of the developed model. The results of the developed model reveal proper workability represented by running the developed coding scripts that correctly reflect the segregated maintenance plans into schedules integrated with the developed BIM model.