The potential for sea level rise inundation of critical transportation infrastructure rises as the threat of climate change continues. Inundation of public transportation including railroads and bus routes, specifically those located in low-lying coastal areas, are vulnerable to these impacts. Therefore, identifying vulnerable facilities in order to implement adaptation planning practices is essential to protecting these facilities and avoiding impacts on mobility. This research focuses on the application of the Transit Inundation Modeling Method (TIMM) to a transit network (railways and bus routes) in Philadelphia County, Pennsylvania. TIMM is developed based on the need to identify transit infrastructure systems that are vulnerable to sea level rise using Geographic Information Systems (GIS). Applying TIMM to a real-world transit network provides an example for how transit agencies throughout the nation can begin to identify at-risk links and nodes based on potential sea level rise inundation levels.