What must be done after removing the cutting key during the uncoupling process?

After removing the cutting key during the uncoupling process, it is essential to depress the Motorman's Bypass and apply power. This action is necessary because it allows for safe control of traction and movement, ensuring that the system remains operational and can be maneuvered as needed. The Motorman's Bypass is a safety feature that enables the motorman to override certain automatic systems in order to maintain control over the train’s power systems.

This step is crucial for preventing accidental movement of the train, allowing the operator to manage the vehicle's functions effectively and safely after a key component like the cutting key has been removed. Engaging the Bypass ensures that any immediate operational functions are adequately handled, maintaining control of the situation during the uncoupling process.

Other considerations, like applying brakes or confirming brake pressure, may also be necessary in the overall safety protocol, but the immediate action required after removing the cutting key focuses on ensuring power control through the Motorman's Bypass feature.