Which feature indicates a non-pressure or low-pressure tank car?

Which feature indicates a non-pressure or low-pressure tank car?

• A. Exposed fittings
• B. A sealed inner tank
• C. A large external dome
• D. A double-walled insulated structure

Answer: (A)

Non-pressure or low-pressure tank cars are designed for liquids that don’t need to be kept under pressure, so you won’t see a dome housing the valve gear. A clear sign is that the fittings and valves on top are exposed and directly accessible. This simple, open arrangement contrasts with pressure tank cars, which use a large external dome to enclose relief and valve equipment needed for maintaining pressure. The other features point to different specialized designs—sealed inner tanks, domes, or double-walled insulation indicate containment or insulation for pressurized, cryogenic, or high-temperature service rather than standard non-pressure service.

Non-pressure or low-pressure tank cars are designed for liquids that don’t need to be kept under pressure, so you won’t see a dome housing the valve gear. A clear sign is that the fittings and valves on top are exposed and directly accessible. This simple, open arrangement contrasts with pressure tank cars, which use a large external dome to enclose relief and valve equipment needed for maintaining pressure. The other features point to different specialized designs—sealed inner tanks, domes, or double-walled insulation indicate containment or insulation for pressurized, cryogenic, or high-temperature service rather than standard non-pressure service.