This study assesses the potential for domestic double-stack container transportation and the implications of expanded double stack systems for railroads, ports, and ocean carriers. The study suggests that double-stack service can be fully competitive with trucks in dense traffic corridors of 725 miles or more. There are opportunities to substantially increase double-stack service in existing corridors and to introduce double-stack service in secondary corridors, in outlying areas near major hubs, and for refrigerated commodities. To meet the challenge of providing and marketing a reliable, high quality, door-to-door service, railroads may have to take unaccustomed steps into marketing and customer service, or become strictly line-haul carriers. Ports must accommodate international double-stack growth, but they will be only indirectly affected by domestic containerization. Intermodal affiliates of ocean carriers will retain their leadership role in domestic containerization, while the ocean carriers themselves concentrate on international movements and markets.