Which action should be completed before restoring power while installing bus jumpers?

Verifying that power is removed is a crucial step before restoring power when installing bus jumpers. This action ensures the safety of personnel working on or near the electrical systems and prevents the risk of electrical shock or equipment damage. It involves confirming that all sources of electricity have been properly disconnected and that systems are de-energized. This precaution is vital, as improper handling of electrical equipment can lead to serious accidents.

In the context of the other actions listed, charging the train typically involves re-establishing power, which would be inappropriate at this stage. Inspecting for damage again might be part of a thorough procedure, but it's secondary to ensuring safety by removing power first. Calibrating the pressure gauge is unrelated to the power restoration process and does not impact the safety protocols necessary for working on electrical systems. Thus, verifying that power is removed stands out as the most critical action to take before any other steps can be safely executed.