If defective air brake devices cannot be corrected, whom must you notify?

Answer: B — Train Dispatcher and Mechanical Help Desk

When defective air brake devices are identified and cannot be corrected, it is crucial to notify the Train Dispatcher and the Mechanical Help Desk. This is primarily because the Train Dispatcher oversees the safe movement of trains in the area and needs to be informed about any defects that could affect train safety and operations. Additionally, the Mechanical Help Desk is responsible for coordinating repairs and ensuring that necessary actions are taken for maintenance and safety checks of the train's equipment. The involvement of both these roles ensures a prompt response to the issue, which is vital for maintaining safe rail operations. This process allows for an accurate assessment of the situation, dispatching maintenance personnel if needed, and informing all relevant parties to prevent any accidents or incidents arising from the defective equipment.