What distinguishes a pressure tank car from a nonpressure tank car?

• A. Nonpressure cars can only carry gases
• B. Pressure tank cars carry liquefied compressed gases
• C. Nonpressure cars are used for hazardous materials only
• D. Pressure tank cars are smaller in size compared to nonpressure cars

Answer: (B)

Pressure tank cars are specifically designed to transport liquefied compressed gases under high pressure. This design allows the contents to remain in a liquid state during transport, even though they are gases at atmospheric pressure. These types of cars have reinforced bodies and safety features to handle the pressures involved, making them suitable for carrying substances such as propane, butane, or anhydrous ammonia.

In contrast, nonpressure tank cars typically do not have the structural reinforcements necessary to handle high-pressure contents. They are used for transporting liquids that are not highly volatile or do not need to be kept under pressure, such as certain chemicals, oils, or water. The focus on pressure in the design of pressure tank cars clearly distinguishes them from nonpressure tank cars based on what they are specifically engineered to carry.