What part of the rail tank car allows for fuel expansion due to temperature changes?

The dome of a rail tank car plays a crucial role in managing fuel expansion due to temperature changes. This structure is typically located at the top of the tank and serves multiple functions, including allowing for the venting of gases and providing access for loading and unloading operations.

When fuel is subjected to varying temperatures, it expands or contracts. The dome accommodates this change by allowing for space or vapor pressure build-up, ensuring that the tank remains safe and operational under different environmental conditions. This design helps prevent over-pressurization and potential spills or leaks during temperature fluctuations.

Understanding the function of the dome is critical for ensuring the safety and integrity of fuel transportation. The other parts of the rail tank car, such as the shell, manway, and underframe, do not specifically address the needs for managing thermal expansion, which is why they are not the focus of this question.