is one of the country's three industrial pillars. Machinery and electronic equipment, leather, food processing, chemical and metallurgical industry are Santiago Province's most important industries. The predominance of the service sector can be explained by the activity from the following industries, among others: electricity, gas, water, construction, commerce, transportation and communication, financial services, housing, education, health, and public administration. Transportation and communication Because Santiago Province includes the city of Santiago, the network of roads are important elements in the province's transportation system. The principal north-south routes are: Route 5 (Autopista Central) The basepoint for numbering the kilometers of the "Central Highway", the Chilean portion of the Panamerican Highway is in Santiago Province. This Kilometer Zero falls at the intersection with the Alameda del Libertador Bernardo O'Higgins. The highway, nicknamed "Norte-Sur" ("North-South"), consists of quality pavement and two- and three-lane roads. Route 68 This route links Santiago with Valparaíso, Viña del Mar, and the summer resorts and beaches in the fifth region of Valparaíso. In addition, it connects the towns of Casablanca and Curacaví. The toll highway, consisting of two- and three-lane sections of well-maintained pavement, extends for 115 kilometers. Route 78 (Autopista del Sol) The "Highway of the Sun" is a toll road that links Santiago with San Antonio, and from there connects to other coastal towns including Llolleo, Cartagena, El Quisco, and Algarrobo. It also connects to the more central Melipilla, Talagante, El Monte, Padre Hurtado and Peñaflor. Route 78 extends 110 kilometers. Route G-21 This 40 kilometer route joins Santiago with the winter resort towns of Farellones and Valle Nevado. Route G-25 This route connects Santiago and the province of Puente Alto with Cajón del Maipo. It extends roughly 70 km to its termination in the town of El Volcán. Roads and railways Other important highways in Santiago province are its network of Autopistas Urbanas (urban highways). Santiago's first toll roads began to operate near the end of 2004. The tolls for uctronic payment system called Televía'' or TAG. Vehicles must carry TAG devices to use the highways. The main highways in Santiago province are: Autopista Central Autopista Costanera Norte Autopista Vespucio Norte Express Autopista Vespucio Sur The province's railroads are a vital form of daily mass transit. They are operated by the state agency EFE. It provides a continuous railroad between the cities of Valparaíso in Valparaíso and Puerto Montt in Los Lagos. The trains of Metrotrén