Extra tunnels for Toronto Crosstown LRT Jan 2013
Peter Kenyon, TunnelTalk
- A last minute alignment change to the Toronto Crosstown LRT means an additional 1.1km of twin running tunnels will be added to the construction package for the eastern underground contract.
Fig 1. Underground alignment now extended from Laird-Don Mills Station
- Project owner Metrolinx had previously intended only to run Crosstown 11km underground from Black Creek Station in the east as far as Laird Station in the west (Fig 1). Tunneling will now be continuous as far as Don Mills Station.
- The change, forced by land contamination problems affecting the location of the planned eastern TBM launch site at Brentcliffe Road, just east of Laird, means that 12.1km of the total 20km alignment between Jane in the west and Kennedy in the east will now run underground.
- From two options considering revised TBM launch sites, Metrolinx has selected Option 2. This involves a longer tunnel alignment than previously planned, but avoids the need for separate drives. Under Option 1 the TBMs would have had to be extracted at the end of their eastern drives to Yonge Street (Eglinton West Station) for transportation back to the launch site and relaunch on a short eastern drive to Laird Station.
- Completion and submission of the necessary amendments to the 2010 Environmental Assessment have put back the schedule for construction tendering, although Metrolinx was unable to confirm by how long.
- Metrolinx spokeman Malon Edwards told TunnelTalk: "We are proceeding as quickly as possible but we don't know at this point what effect this will have on the procurement of the tunneling contract and the construction schedule."
- Back in September last year Metrolinx said it expected to issue RFQs for the 5.25km eastern tunnel section (now adjusted to 6.35km) by the end of 2012, and award the construction contract by Summer 2013.
- The extra section of tunnel means that planned at-grade stations at Leslie and Ferrand will now no longer be built. At an estimated cost of Can$80 million, Metrolinx considers moving the proposed Leslie Station underground, unjustifiable, given the low projected passenger numbers at this location. Extra trackwork east of Don Mills Station means there is now no room for a station at Ferrand.
- Savings accrued from not having to build these two stations and not having to widen the bridge crossing over the Don River now that the alignment runs underneath it, "offset the additional tunnel costs" said the Metrolinx spokeman.
- Meanwhile, arrival on site is expected next month (February 2013) of the first of two owner-procured Caterpillar TBMs that will excavate the 6.25km of twin running 5.75m i.d. western tunnels for the Obayashi/Kenny/Kenaidan/ Technicore JV.
- The Metrolinx spokesman said: "The launch shaft is expected to be available to the tunnel contractor in early February 2013. The first TBM is expected to arrive at the launch shaft in late February 2013 and tunneling is then expected to begin in late April. The second TBM is expected to arrive at the launch shaft in late April 2013. It is expected to start tunneling in late June 2013".
- A further two Caterpillar TBMs will excavate the eastern tunnels.
Detailed revised tunnel alignment plan (Laird-Don Mills)
First tunnel award for Toronto Crosstown LRT - TunnelTalk, September 2012
Toronto axes 17km of tunnels - TunnelTalk, May 2012
New LRT plan would cut Eglinton tunneling - TunnelTalk, January 2011
Tender schedule for the 17.5km Crosstown LRT for the Toronto Metro, Canada - TunnelTalk, November 2011
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