What is the role of the contact wire in an overhead traction system?

• A. It provides the electrical path to the pantograph
• B. It provides the electrical path to the grounding rod
• C. It anchors the track to the ballast
• D. It insulates the system

Answer: (B)

The contact wire’s job is to provide the electrical path to the pantograph. It carries the traction current from the power substation to the train, and the current returns through the rails back to the substation. Grounding rods are part of earth safety and not the normal current path, and the other roles (anchoring the track to ballast or insulating the system) are handled by different components.