A TBM named for Eliza Leggett, an active participant on the underground railroad, and later a suffragist, has been tunneling for the past 6 months on the massive I-75 reconstruction project in metropolitan Detroit. The 14.5-ft diameter TBM will excavate 4 miles of drainage tunnel which will not only drain I-75 but will improve drainage in nearby neighborhoods as well. The current drainage system on I-75 requires 7 pump stations. The new drainage tunnel will require only 1. And because of the large storage capacity of the tunnel, 20 million gallons, it can safely drain the freeway while allowing the pump station to prioritize pumping for the adjacent neighborhood first to keep residents from flooding out.
The launch pit began construction in 2019 and is approximately 60 feet in diameter, and 100 feet deep. The entire train is approximately 400 feet long, with some portions partially constructed ahead of time, and assembled one segment at a time in the launch pit. The tunnel is scheduled to be completed in mid-2023. More information can be found at Construction Equipment Guide (CEG).