线路 (xiànlù) means a physical line or route, such as a bus route, subway line, or electrical circuit. It is more concrete than 路线 (lùxiàn 'route, itinerary'), which can also refer to a political or abstract line. For electrical wires, 线路 is broader than 电线 (diànxiàn 'power cord') and more specific than 线 (xiàn 'thread, wire').