Double-stack wells

The boom in intermodal traffic, particularly containerized imports during the 1980’s and 1990’s, led to the development of the double-stack intermodal well car. Essentially, this railcar is a hybrid between a flat car and a gondola. The unique design creates a low center of gravity and enables two intermodal containers stacked on top of each other to clear nearly all height restrictions on the railroads (double-stack loads are permitted to reach 20’3” above the top of the rail).

Another interesting feature of double-stack intermodal cars is that many are articulated (sharing wheels between the car’s units), which reduces slack action and improves the ride quality for fragile cargo. Intermodal double-stack wells come in different configurations. The most common are 5-unit, 40-ft articulated cars (265-ft in total length per car) for carrying 20-ft, 40-ft, and 45-ft international containers, and 3-unit, 53-ft articulated cars (203-ft in length) for transporting 53-ft containers. TTX is a major supplier of intermodal double-stack wells to the industry and owns more double-stack well cars than any other entity.