Mitsubishi TBM Arrives in Seattle for Beacon Hill TunnelA Mitsubishi tunnel boring machine arrived in pieces on 11th July on the Seattle waterfront to be assembled over the next two months. After the TBM is assembled, it will be guided a short distance on an anti-skid slab to the west portal to begin boring two 1.6 km tunnels through Beacon Hill in end-October 2005. The machine has been manufactured in Kobe, Japan for Obayashi. The EPB TBM itself is 10.2 m long and back-up equipment up to 100 m long will trail behind as it drives its way through Beacon Hill. It weighs 360 tons (520 tons with the back-up). The TBM is equipped with a 6,444 mm-diameter cutterhead holding 104 drag bits and 41 shell bits. The total installed main drive power is 800 kW, the thrust force is 40,000 kN and the maximum rotation speed is 2.5 rpm. The maximum C/H torque is 6,031 kNm. Crews will install precast concrete segments in the back-up equipment and lay track as the boring machine chews through the hill. The geology is mostly clay. Visit www.mhi.co.jp and www.obayashi.co.jpThe tunnel will be lined with 1.52 m-wide rings of seven segments. The maker of the segments is Technopref Industries of Montreal. The supplier of the laser guidance system and segment erection system is Enzan. For mucking-out, a screw conveyor and tunnel conveyor will be installed in the tunnel, with muck cars as needed. The machine will take six months to tunnel through Beacon Hill. It will emerge on the south side of South McClellan Street. At that point, the machine will be taken apart and transported back to the west side of Beacon Hill to start all over again on the second tunnel. Tunnelling is expected to be finished by January 2007. Visit www.enzan-k.comOther underground works include the Beacon Hill station complex consisting of the 15.24 m-diameter main shaft to house the elevators, a concourse tunnel, a 9 m-diameter ancillary shaft to house emergency stairs, a ventilation adit and cross passages. At the main shaft, crews are doing the barrel vault for the concourse cross adit. To date, there is no activity at the ancillary shaft.The Beacon Hill tunnel and station complex are part of Sound Transit's Central Link light rail project. The 22.5 km line, scheduled to open in mid-2009, will run from Westlake Center downtown to South 154th Street in Tukwila. Construction is under way on all five segments of the initial line: underground downtown, Sodo, Beacon Hill, Rainier Valley and Tukwila. Click us/42. Read E-News Weekly 30/2003 & 13/2003. Visit www.soundtransit.org 31-32/05.