What key is used to access elevator machine rooms in metro stations?

The Metro Master Key is essential for accessing elevator machine rooms in metro stations because it is specifically designed to unlock secured areas that house critical infrastructure such as elevators and other operational facilities. This key ensures that only authorized personnel can access machinery and systems vital for the safe and efficient operation of the metro service. The use of a specialized key like the Metro Master Key helps maintain security and operational integrity within the transit system, preventing unauthorized access and ensuring that only trained individuals can perform maintenance or emergency procedures.