There are four operational tracks starting at Howard Street, continuing on to Armitage Avenue. During weekday rush hours, the Purple Line runs express on the outer tracks, skipping all stops until Wilson Avenue, and then to Belmont Avenue. From Belmont Avenue to Armitage Avenue, the Purple and Brown Lines share the outside tracks and both make all stops along the route. From just south of Armitage Avenue to just north of Chicago Avenue, they are on a two track line on a 4-track structure. After the North Shore Line ceased operations in 1963, the outer tracks in this area were rarely used and received next to no maintenance; they were permanently taken out of service in 1976.