Thrall Corporation built 75 single-unit double-stack well cars with a very unique appearance in the early 1990s. These cars used unique Waggon Union trucks, initially developed for use on the prototype Well-Runner car number DTTX 110023.

TTX officially classified the cars TWF10 and they allotted the 54000-54074 number series for a total of 75 cars. As of 2021, approximately twenty percent of these cars were still in active service, a testament to the rugged design and the car’s durability. The use of the Waggon Union trucks and their unique design that supports the weight of the car from the sides rather than from the center-bowl required a one-of-a-kind car design. The truck wheelbase was considerably shorter than other cars and the ends of the car were designed to evenly distribute the car weight near the edges of the carbody.

These cars look like nothing else, having heavy side-sill members and the enclosed car ends that partially obscure the trucks themselves. This feature and the low-slung appearance of the cars were instrumental in the cars being nicknamed “battleships” by those that regularly see them in mainline double-stack service all over the country.

The wells of the car can accommodate up to a 48-foot container but can also accommodate two 20-foot, one 40-foot or one 45-foot container in the well. The cars are often seen loaded with large overhanging containers in the upper position of the car. The unique truck design was not repeated due to certain maintenance requirements and these cars remain the champions in single well design uniqueness.