Kaolin, a fine usually white clay, is produced by the natural chemical weathering of aluminum silicate minerals such as feldspar. Mined in the southeastern part of the United States (primarily Georgia and Florida, and to a lesser extent South Carolina), kaolin is used in the manufacturing of ceramics, bricks, light bulbs, and cosmetics, as well as being used as a food additive and in medicines. The largest use is in the manufacturing of paper, especially in creating glossy paper. Kaolin is shipped both as a dry powder in covered hoppers and in tank cars mixed with water as a slurry. In the slurry form, the weight of the water requires the tank cars be smaller capacity compared to other liquids such as ethanol and LPG. Identical tank cars are also used to haul calcium carbonate slurry, used in the making of lime and cement.

One of the more modern versions of the clay slurry tank car is designed and manufactured by UTLX Manufacturing Inc, formerly Union Tank Car. The car is a 286K (referring to a 286,000 pounds gross rail load limit) design with a capacity of approximately 16,000 gallons. The capacity varies slightly between UTLX and Englehard, the operators of the cars. The car is an AAR Plate C clearance car with a 111 inch I.D. tank and an overall length of 44 feet. For complete bottom unloading, the car incorporates a Funnel-Flow design. The cars are lined and kept in dedicated service to avoid contamination.

Era: 1999s to now

? ALL NEW tooling
? Fully assembled
? Scaled from manufacturer's drawings
? Weighted for optimal performance
? Photo-etched end platforms
? Metal grab irons
? RP25 profile machined metal wheel sets
? Equipped with McHenry AAR upper/lower shelf couplers per prototype practice
? UTLX cars will each have slightly different paint and reporting mark variations