This past weekend was a sight to behold for many self-described 'transit geeks' as two tunnel boring machines (TBMs) successfully made an above-ground journey outside Eglinton West Station at Allen Road. Dennis and Lea, named after the Mount Dennis and Leaside neighbourhoods, were carefully hoisted out of the extraction shaft on Eglinton Avenue West on two separate nights, making their crawl over to a launch shaft a short distance to the east.
The 19-kilometre Crosstown LRT includes a ten-kilometre portion underground. The tunnel is being carved out by four TBMs, with Dennis and Lea pushing east from Black Creek Drive to Yonge, while Humber and Don are expected to begin pushing west from Laird Drive to Yonge this summer. All four TMBs are scheduled to meet at Yonge and Eglinton at the end of next year.
Two large gantry cranes were positioned above the extraction and launch shafts, performing the duty of hoisting and lowering the two machines. Though the TBMs had been partially disassembled, they weighed-in at over 400 tonnes each. The machines themselves are ten metres long and six metres wide, but are followed by over 70 metres of trailer gear. Some of the trailer gear is visible in the video below by Jack Landau, which depicts both Dennis and Lea about 20 metres underground, pre-move on Wednesday:
The hoisting of Dennis began around 9 PM Friday night, with the entire machine becoming visible at about midnight. A throng of onlookers crowded around the site, taking advantage of hot chocolate and coffee provided by Metrolinx. A driverless modular trailer, boasting an impressive 13 rows of 16 wheels, was intricately positioned below the massive machine. The early Saturday morning move was deemed necessary as a precaution, coinciding with the normal subway closure hours. Once in place, Dennis made its way along Eglinton Avenue, beginning a bit before 2 AM.
The machine came to a momentary halt after it cleared the gantry crane, allowing workers to place a banner with 'Dennis' written on it.
As Dennis moved eastward, it carefully passed over a temporary bridge deck which had been installed in February. The deck reinforces the road and ensures a smoother ride for the machine.
Following its move over the bridge deck, Dennis began its final short trip to the second gantry crane, positioned over the launch shaft at the east side of Allen Road.
Now in position, Dennis was hooked into safety by the gantry crane, allowing the massive flatbed trailer to be pulled out from underneath the machine.
Now held in the air by the gantry crane supports, workers began the delicate process of lowering Dennis into the shaft. The move from the west crane to the east crane, once in motion, only took about 20 minutes. The more substantial aspect of the operation was the hoisting and lowering of the machine, which was mostly submerged by 5:30 AM.
A timelapse video put together by Forum contributor Bryan Bonnici depicts the move and the descent in further detail:
The entire operation was replicated on Saturday night, as Lea was lifted out of the extraction shaft and transported along Eglinton Avenue. Photographs of this move are a little more scarce, as the procedure was unexpectedly moved up to 10:30 PM from its original timeslot of 2 AM Sunday morning.
The next phase of tunnelling is expected to begin this June, as Dennis and Lea continue their trip eastbound. The entire project, including its 25 stations, will be operational by 2020.
For more information about the Crosstown LRT, visit the dataBase files linked below. To get involved in the discussion, check out the associated Forum thread or a leave a comment in the space provided at the bottom of the page.