Which tank car is smaller than most tank railcars and has a protective black band under the dome area?

The tank car that is smaller than most tank railcars and features a distinctive protective black band under the dome area is typically associated with specific design characteristics that aid in identifying the type of contents it holds, especially for corrosive materials. Corrosive tank railcars are designed to transport hazardous materials that could cause damage to other materials or structures, hence the need for additional protective measures.

The black band under the dome serves as a visual indicator, allowing for quick recognition of potential hazards by emergency responders and rail personnel. In terms of size, corrosive tank railcars are generally more compact compared to other types, making them easier to handle in various transport scenarios.

Other tank cars, such as high pressure, non-pressure, and cryogenic types, have different operational specifications and design features, primarily related to the pressures they carry and the temperatures required for the materials inside. These characteristics do not align with the specific identifiers associated with corrosive tank railcars, making it clear why the chosen answer correctly corresponds to the description in the question.