Main Line 29901

Main Line 29901 is a storm drain tunnel in Los Angeles. The plains for the drain are available on the city's website

This storm drain is large enough to support easy exploration and intercepts with U3 Line B to create the Northeast Gallery Complex, home to some of the best street art in the system.

Main Line 29901 is notable for it's changing structure; becoming larger, smaller, horseshoe-shaped, and box-shaped in various areas, while other tunnels generally remain the same size and shape.

Entrance
Main Line 29901 enters at the LA river into a concrete box type opening, and then passes a ladder which leads up to opening into an isolated room just below street level. On the Northeast Gallary Complex map, the entrance is section Beta.

Inner Entrance
Past the ladder, there is a winding passageway which leads to a smaller unexplored tunnel (RHO), and another concrete-box type straightaway which hosts the Robocop painting. On the Northeast Gallary Complex map, this area is section Epsilon.

Upper Gallery
After the straightaway, there is an intersection with U3 Line B at point X-Ray, a small crossover tunnel poorly documented on public maps. From this point on, the Upper Gallery is a long, straight, concrete box section full of street art extending about a mile.

Most street art is concentrated in this area of the Northeast Gallery Complex. This area is referred to as the Upper Gallery.



Gold Tunnel
After about a mile of the Upper Gallery, the concrete box changes to a horseshoe-shaped tunnel, and is painted completely metallic gold by unknown parties for several hundred feet.

Northeast Fountains
Past the gold tunnel is the site of natural deposits from hard water or poured concrete creating interesting shapes from drainage areas, named the Northeast fountains. Past this area, there is a long stretch in which the tunnel gets smaller in size until it can no longer be explored.