Which of the following descriptions best matches a pressure tank car?

• A. A car with a cylindrical tank and exposed fittings
• B. A car designed to carry liquids at atmospheric pressure
• C. A car with a cylindrical tank and a covered dome containing fittings and valves
• D. A non-pressurized, open-top tank

Answer: (C)

Pressure tank cars are built to carry liquids under pressure, so a key identifying feature is a cylindrical tank with a covered dome that houses the fittings and valves. The dome protects the loading/ unloading connections, pressure-relief devices, and associated hardware from damage and weather, helping prevent leaks and ensuring safe operation. Exposing the fittings (as in a car with exposed fittings) would increase the risk of leaks or tampering and isn’t how pressurized service is designed. A car designed for atmospheric-pressure liquids wouldn’t need a dome over the fittings, and a non-pressurized open-top tank isn’t suited for pressurized contents.