While usually referred to as an insulated boxcar, the prototype for this car, according to the Association of American Railroads (AAR), is technically a bunkerless refrigerator car, class RBL. Built by Evans Products Company at Blue Island, Illinois from 1969-1977, these cars were designed for shipments that need protection from temperature extremes but do not require refrigeration. They have hardwood floors and at least 3" of insulation in their sides, ends and roofs. Produce is a common cargo. The cars' length and wide 16' door openings have also made them popular with plywood and lumber shippers.

In contrast with typical sliding doors, the plug doors on these cars are pulled into the door opening when the door is latched. This produces a nearly watertight and airtight seal, protecting the load and helping to keep a more constant inside temperature. A cushioned underframe also helps protect the load from shock, hence the "DF" (for "damage free") logo found on some of these cars.

Evans Products built nearly 4.400 of these cars, selling or leasing them to a large number of North American railroads and private owners. Although the last of these cars are nearing the end of their allowable 40-year service life, they can still be found in U.S. freight trains today.

High quality, traditionally sized RailKing Freight Cars provide detailed bodies and colorful paint schemes for the O Gauge railroader. MTH makes an enormous variety of RailKing Freight Cars, including many different car types and roadnames. No matter what era or part of the country you are modeling, RailKing is sure to have something for you.