Between 75 and 80 million people use the system every year. About 70% of the people living in the area use the system. Plans include gradually introducing 4 trains per hour on most lines, and to extend the offer to 4 trains per hour between Zürich and Winterthur during the whole day, and not just during rush hour. A new tunnel was built in Zürich main station. This tunnel allows a direct connection from Zürich main station to Oerlikon and the airport, without a change of direction. 