The Saudi Arabian authorities have announced the launch of the world's longest unmanned metro system. Three lines of the new transportation system have already started their work in the capital of the country. The system includes 85 stations. The new transportation system is designed for a daily passenger flow of 3,600,000 people. It is designed to reduce congestion on the capital's surface roads and cut carbon dioxide emissions by 12,500,000 tons per year. The rolling stock will be Alstom Metropolis (69 units) and Innovia Metro (47 units) electric trains. The carriages are divided into 3 classes: first class, family class and for bachelors. They are equipped with LED lighting, information boards and air conditioning. The automatic train control system ensures smooth movement between stations and operation of car doors. To improve passenger safety, they have special protective walls with a sliding mechanism. In January next year, one more line will be added to the existing lines, and then two more are planned to be launched. In total, the length of the automated metro lines will be 176 kilometers. They will cover key districts of Riyadh, business centers and cultural attractions