A liquid hydrogen tank car, also called liquid hydrogen tank wagon or liquid hydrogen tanker wagon is a railroad tank car

Tank car

A tank car is a type of railroad rolling stock designed to transport liquid and gaseous commodities.-Timeline:...

 designed to carry cryogenic liquid hydrogen

Liquid hydrogen

Liquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.To exist as a liquid, H2 must be pressurized above and cooled below hydrogen's Critical point. However, for hydrogen to be in a full liquid state without boiling off, it needs to be...

 (LH₂). LH₂ tank cars with a capacity of 17000 pounds (7,711 kg) are used for transcontinental transport .

Design

The pressure

Pressure

Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...

 within the tank is 25 psi (172.4 kPa) or lower with a temperature below 20.27 K (−423.17 °F) and a boil-off rate of 0.3% to 0.6% per day The tank

Pressure vessel

A pressure vessel is a closed container designed to hold gases or liquids at a pressure substantially different from the ambient pressure.The pressure differential is dangerous and many fatal accidents have occurred in the history of their development and operation. Consequently, their design,...

 is double walled like a vacuum flask

Vacuum flask

A vacuum flask is an insulating storage vessel which keeps its contents hotter or cooler than its surroundings. Invented by Sir James Dewar in 1892, the vacuum flask consists of two flasks, placed one within the other and joined at the neck...

 with multi-layer insulation

Multi-layer insulation

Multi-layer insulation, or MLI, is thermal insulation composed of multiple layers of thin sheets often used on spacecraft. It one of the main items of the spacecraft thermal design, mainly intended to reduce heat loss by thermal radiation. In its basic form, it does not appreciably insulate...

, with the valve

Valve

A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...

s and fittings

Pipe fitting

Pipe fitting is the occupation of installing or repairing piping or tubing systems that convey liquid, gas, and occasionally solid materials...

 enclosed in a cabinet at the lower side or end of the car.

Classes

Cryogenic liquid tank cars in the USA are classified as follows:

• DOT
  United States Department of Transportation
  The United States Department of Transportation is a federal Cabinet department of the United States government concerned with transportation. It was established by an act of Congress on October 15, 1966, and began operation on April 1, 1967...
  
  113 (Cryogenic liquid tank cars)
• AAR
  Association of American Railroads
  The Association of American Railroads is an industry trade group representing primarily the major freight railroads of North America . Amtrak and some regional commuter railroads are also members...
  
  204W (Cryogenic liquid tank cars)
• AAR
  Association of American Railroads
  The Association of American Railroads is an industry trade group representing primarily the major freight railroads of North America . Amtrak and some regional commuter railroads are also members...
  
  204XT (Inside Box Car)

See also

• Compressed hydrogen tube trailer
• Hydrogen economy
  Hydrogen economy
  The hydrogen economy is a proposed system of delivering energy using hydrogen. The term hydrogen economy was coined by John Bockris during a talk he gave in 1970 at General Motors Technical Center....
  
  
• Hydrogen infrastructure
  Hydrogen infrastructure
  A hydrogen infrastructure is the infrastructure of pipes and stations for distribution and sale of hydrogen fuel.-Hydrogen pipeline transport:Hydrogen pipeline transport is a transportation of hydrogen through a pipe as part of the hydrogen infrastructure...
  
  
• Liquid hydrogen tanktainer
  Liquid hydrogen tanktainer
  A liquid hydrogen tank-tainer also known as a liquid hydrogen tank container is a specialized type of container designed to carry cryogenic liquid hydrogen on standard intermodal equipment...
  
  

• Liquid hydrogen trailer
  Liquid hydrogen trailer
  A liquid hydrogen trailer is a trailer designed to carry cryogenic liquid hydrogen on roads being pulled by a powered vehicle. The largest such vehicles are similar to railroad tanktainers which are also designed to carry liquefied loads. Liquid hydrogen trailers tend to be large; they are...
  
  
• Vacuum flask
  Vacuum flask
  A vacuum flask is an insulating storage vessel which keeps its contents hotter or cooler than its surroundings. Invented by Sir James Dewar in 1892, the vacuum flask consists of two flasks, placed one within the other and joined at the neck...
  
  
• Vapor-cooled neck
• Vapor-cooled radiation shield

External links

• Liquid Hydrogen Transport by Rail