The future of the U.S. commuter rail industry is inextricably linked to that of the freight railroads. Because of recent mergers and associated operating issues, some shipper interests are seeking fundamental change in the organization of freight railroading. Under proposals for open access, railroads judged to be abusing a monopolistic position or providing inadequate service would be required to accommodate competing operators. As in the telecommunications and natural gas industries, infrastructure and service provision would be disaggregated and rail freight shippers could choose among different railroads. Open access is expected to lead to greater volatility in freight scheduling, as bulk shippers change service providers to maximize their commercial advantage. With freight railroads already at capacity in several metropolitan areas, open access would probably exacerbate capacity problems. The possible effects on commuter operations in Washington, D.C., and Chicago are analyzed. If the United States moves toward some form of open access, commuter railroads must ensure that their operating rights are fully preserved, especially during rush hours.