A look inside the new-look SR 99 tunnel

Not long ago, you might have been able to fit a five-story building inside the cavernous circumference of the SR 99 tunnel. Not anymore. From the south end of the tunnel to the back end of Bertha, the SR 99 tunneling machine, crews have filled the tunnel with long stretches of walls and roadway sections of the future underground highway. The series of photos below shows just how much the landscape inside the tunnel has changed. 
In the first photo, you are looking north at the future southbound roadway deck. Crews are building the deck, walls and foundations in 54-foot-long sections. By mid-March 2015, crews had placed the concrete decks for the southbound roadway – a continuous stretch of nearly 450 feet. 
Looking south from the same location provides a view of crews turning Bertha’s launch pit into the double-deck roadway that will take drivers to the surface near South Royal Brougham Way.
Where’s Bertha in this north-facing image? She’s on the other side of the red platform that crews are using to build the tunnel’s decks and walls. Hint: Look for the blue “12” flag.
Speaking of “12” flags, this final photo is the view from below, where another flag is casting a shadow on the underside of the southbound roadway deck. Construction of the northbound, or bottom, roadway deck will come later, after Bertha is done tunneling. Until then, crews will use that space to move equipment, people and material such as tunnel segments through the tunnel.