The section from Flinders Street station to Victoria Park was built later than the rest of the line, which was originally connected to the suburban system via the now-closed Inner Circle railway line. There is evidence that the line was originally intended to be connected via this route, but geography and existing suburban development made it a problematic situation. The section to Victoria Park runs through two tunnels under a low ridge just east of the city, but most of the rest runs on an embankment that carries the line above numerous main roads and suburban side streets.