What must be done after making an add to check the connections?

After making an add, charging the train is essential because it ensures that the train's air brake system is pressurized and functioning properly. This process involves refilling the air reservoirs to the required pressure levels, which is critical for the safe operation of the train and the safety of the crew and cargo. If the train's air system is not adequately charged, it may lead to ineffective braking, increasing the risk of accidents or derailments.

Charging the train also allows the crew to verify that all connections, including hoses and brake pipes, are secure and working correctly. This step prevents potential air leaks and ensures that the entire braking system is operational. Completing this procedure is a fundamental safety measure that must follow any adjustments or additions to the train's configuration.

Other options, while potentially related to train operations, do not directly address the immediate need to ensure that the air brake system is charged and connected properly. Thus, focusing on charging the train reflects the critical nature of maintaining safety standards in railway operations.