The Sunset Boulevard segment was established in 1895 by the Pasadena and Pacific Railroad as a narrow gauge line.

Trips though the Hill Street Tunnel began on September 15, 1909, allowing cars a more direct route to Downtown Los Angeles.

[3] The route was converted to standard gauge that same year,[4] with five miles (8.0 km) of track gauge-converted the night before the tunnel's opening.

[3] The line was acquired by Pacific Electric in 1911 as part of the Great Merger, and the company assumed operations.

The Red Cars exited the station (or later the Subway Terminal Building) at ground level directly into Hill Street.

On Sunset Boulevard, dual tracks ran westerly in the center of the pavement, crossing Grand Avenue, Figueroa Street, and over the Pasadena Freeway.

The line continued northwesterly on Sunset before turning west onto Hollywood Boulevard, then zig-zagged its way southwesterly, primarily on private right-of-way, between La Brea and Fairfax avenues down to Santa Monica Boulevard, continuing down Santa Monica before terminating at PE's Beverly Hills depot located on Canon Drive between "Big" and "Little" Santa Monica boulevards.

[12] A separate service operated locally all the way through to Venice after Beverly Hills via the Sawtelle Line.