SUDBURY — Eversource has begun construction on a high-voltage transmission line that will stretch 9 miles along a former railway corridor from Sudbury to Hudson.

The utility plans to connect two stations with a 115-kilovolt (kV) transmission line underneath a 7.6-mile stretch of a former Massachusetts Bay Transit Authority rail corridor. It will start at the Eversource substation in Sudbury and end in Hudson, passing through small parcels of land in Marlborough and Stow along the way. The remaining 1.4 miles will be installed under streets in Hudson, according to Eversource, finishing at the Hudson Light & Power substation.

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Crews in Sudbury are working on clearing vegetation and irrigation control installation, according to construction updates on Eversource's website. "After these enabling activities are finished, crews excavate and install cable vaults and duct bank," according to a construction update posted earlier this week.

In Hudson, crews worked this week to install a cable vault between Wilkins and Chestnut streets.

"We began construction at the Sudbury substation and on the underground line route in October, and have since continued to make progress," said Eversource spokesperson Chris McKinnon, in an emailed statement. "We will begin similar construction work along Forest Ave. in Hudson next week to install duct banks and three manholes between the Hudson Light & Power substation and the MBTA corridor entrance."

McKinnon said Eversource is aiming to complete the project in late 2023 or early 2024.

Why is Eversource doing this project?

The project was identified as one of about 40 transmission solutions that came from an extended study of the regional transmission system to improve reliability across Greater Boston and "provide access to lower-cost cleaner energy resources for all of our customers," according to McKinnon.

However, Sudbury and Hudson residents have focused on protecting their communities.

The town of Sudbury sued the MBTA in 2017, arguing the lease between the MBTA and Eversource was illegal. Massachusetts Land Court dismissed the case. The town then appealed, but the state Supreme Judicial Court ruled in favor of the MBTA in 2020.

The town of Sudbury has spent approximately $1 million in litigation against the MBTA, according to Select Board meeting minutes.

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In 2021, the Select Board sent a letter to former Gov. Charlie Baker and CEO of Eversource Joseph Nolan, asking whether the project is necessary. The letter calls into question the expectations of the project, as well as mentioning environmental concerns.

"The currently proposed route along the inactive rail corridor through our drinking water supply is unquestionably the most environmentally damaging of the options considered," the letter reads.

The letter goes on to say that the excavation and handling of potential contaminants along the railway may pose risks to wetlands and wells. A December 2021 study examined soil samples of 26 locations along the corridor and found elevated levels of arsenic above state standards in 12 of the sampling locations.

More recently, two Hudson landowners whose properties abut the rail corridor filed a complaint seeking to clarify their claim to the properties and argue that the "taking" of the lands is void.

The MBTA acquired the Mass Central rail corridor in part through a 1976 agreement with Boston and Maine Railroad. The MBTA received more land in 1977 through eminent domain.

This article originally appeared on MetroWest Daily News: Eversource high voltage power line construction Sudbury to Hudson