Two tunnel boring machines moving south
Mining crews continue to make good progress on the twin tunnels between the Maple Leaf portal and the Roosevelt Station construction site. The tunnel boring machine working on the northbound tunnel has traveled about 4700 feet to about NE 78th Street. The TBM building the southbound tunnel has travelled more than 260 feet to approximately NE 92nd Street.
A crucial tool in building the twin Northgate Link tunnels, rubber tired vehicles use a 150 horse power diesel engine to haul the concrete segments that will form one ring of the new tunnel. You can see that the wheels are canted to allow the RTV to drive safely in the circular tunnel.