Gunderson well cars are articulated and come in one, three, or five sections. They are considered one car since each piece is dependant on another. Open Hopper Open hoppers are used top haul coal or rocks. In MoW service, hoppers carry ballast. In revenue service, they usually haul coal.
Hoppers can differ in the number of bays they have.
Refrigerator Car Refrigerator cars are used to haul foods that must be kept cold. Roadrailer Roadrailers are very unique. They are not actually a car, but are specialized truck trailers suspended by wheel bogies and coupler mates. Roadrailers can also be seen on the rear of most Amtrak passenger train. Spine Car Spine cars are used to carry truck trailers.