The tank car is a cylindrical pressure vessel mounted on a rail underframe, designed to transport liquids, liquefied gases, and slurries in bulk. Tanks may be insulated, heated, or cryogenic depending on the commodity. The DOT-111 is the most common general-purpose car, while DOT-117 (the post-2015 enhanced standard) features a thicker steel shell, full head shields, and thermal protection. Pressure cars (DOT-105, DOT-112) handle liquefied gases such as propane, chlorine, and vinyl chloride at higher containment pressures.
Non-pressurized tank for flammable and non-flammable liquids; most common type historically used in ethanol and petroleum service.
Post-2015 retrofit or new-build standard with 9/16-inch steel shell, full-height head shields, and thermal protection blanket for hazmat liquids.
Thicker-walled, pressure-rated tank for liquefied gases such as LPG, chlorine, and vinyl chloride shipped under their own vapor pressure.
Double-walled vacuum-jacketed tank for cryogenic liquids such as liquid nitrogen, liquid oxygen, or liquid helium at very low temperatures.
Interior lining (rubber, stainless steel, or polymer) for aggressive acids, food-grade products, or commodities that must be kept from contact with carbon steel.
Tank cars are indispensable for bulk liquid chemical and petroleum logistics, moving crude oil, ethanol, and hazardous chemicals where pipelines are unavailable or unit-train economics are favorable.