A liquid hydrogen tank car, also called liquid hydrogen tank wagon or liquid hydrogen tanker wagon, is a railroad tank car designed to carry cryogenic liquid hydrogen (LH<sub>2</sub>). LH<sub>2</sub> tank cars with a capacity of are used for transcontinental transport.
The pressure within the tank is or lower with a temperature below 20.27 K () and a boil-off rate of 0.3% to 0.6% per day The tank is double walled like a vacuum flask with multi-layer insulation, with the valves and fittings enclosed in a cabinet at the lower side or end of the car.
Cryogenic liquid tank cars in the US are classified as follows: