The 36th Street Portal is a SEPTA Subway-Surface Lines trolley station. Just south of the corner of 36th and Market Streets (actually on the corner of 36th and Ludlow Streets), it is at this station that the 10 trolley of the Subway-Surface Lines goes into the tunnel after running on the street in West Philadelphia coming from the Overbrook section of Philadelphia. Trolleys run in the tunnel from this station to Center City Philadelphia. At 33rd Street, the 10 trolley connects with the other Subway-Surface Lines which come into the tunnel at 40th Street. After entering the tunnel, the 10 trolley runs under Market Street to Center City Philadelphia. The station itself is above ground right before the tunnel.