> CDPQ Infra was able to take advantage of existing rights of way to create the route, rather than needing to dig costly tunnels or demolish buildings. In one a

> CDPQ Infra was able to take advantage of existing rights of way to create the route, rather than needing to dig costly tunnels or demolish buildings. In one area, they repurposed an old rail tunnel I'm listening to the podcast about Boston's Big Dig (https://www.wgbh.org/podcasts/the-big-dig https://www.wgbh.org/podcasts/the-big-dig), and one of the things that came up in Episode 6 was cost overruns in the 1990s, particularly on the I-93 segment (burying the highway to replace the elevated highway from the 60s). The engineers and administrators had no idea what they would be getting into when they drew up the estimate, because no one really knew what was underground when they started digging 100 feet below street level next to Boston harbor and well below the water table. They found everything - old pilings, sewer tunnels from the 1800s, archaic utilities, and mud that was exceptionally sticky. It turned into a series of change orders which greatly increased the $7.7B original price ($10.8B adjusted for inflation) to $14.8B. TFA mentions the Green Line extension in Boston which has been a costly disaster for different reasons, from ADA compliance to mislaid tracks. https://www.universalhub.com/2023/companies-built-green-line-extension-sue-company https://www.universalhub.com/2023/companies-built-green-line...