TRB’s National Cooperative Highway Research Program (NCHRP) Research Results Digest 313: Cost-Allocation Methods for Commuter, Intercity, and Freight Rail Operations on Shared-Use Rail Systems and Corridors explores issues associated with the initiation of commuter rail or intercity passenger rail service within a shared-use corridor. The report examines current commuter and intercity passenger shared-use rail arrangements; highlights both the allocation of operating and maintenance costs and the arrangements for making infrastructure improvements; and identifies the cost allocation methodologies, capital investment strategies, and other associated issues. In addition, the report investigates opportunities for potential outreach and buy-in efforts among system stakeholders and identifies potential future research needs.