Follow Bertha

Bertha, the SR 99 tunneling machine

The SR 99 tunneling machine, nicknamed Bertha, broke through into her disassembly pit around noon on April 4. This marked the end of her 9,270 foot journey beneath Seattle.

Time-lapse camera

Over the coming months, crews will be disassembling Bertha and removing the machine from the tunnel. This time-lapse camera will capture the work in the disassembly pit.

The project's other time-lapse cameras are posted on the Construction Cameras page.


Video of the breakthrough

A drone helped capture Bertha's breakthrough into the disassembly pit. Below is a 3-minute capture of the breakthrough, complete with sound.


Interior structures progress

For information about progress on the tunnel's interior structures and other tunnel systems, visit the Latest Progress page.