The railroad industry is expected to see increased demand in the United States (U.S.) over the next 30 years. This demand will put a strain on the infrastructure and its ability to provide timely and efficient service. Various technologies are currently available to increase railroad capacity, but in time new trackage will either need to be added to existing routes, built as new routes, or existing routes be upgraded to a higher speed classification. Anticipating these costs is a challenge, since few railroad miles are constructed annually and there are various factors affecting costs. However, it is possible to calculate cost per mile (CPM) accounting for right-of-way (ROW), design and build, materials, communications and signaling, and electrification, where applicable. This thesis presents a methodology for estimating CPM of railroad construction in the U.S. as a function of design speed, geography, land use, number of tracks, and motive power. The proposed CPM estimates were compared to CPM estimates from feasibility studies, and resulted in the majority of costs being replicated by the methodology. The proposed methodology has been developed in an adaptable manner, where future project cost components may be included, creating a dynamic estimation methodology for analysis and planning activities, prior to feasibility study analyses.