The 19th-century Tremont Yard tunnels sit nearly forgotten, lying beneath the corporate offices of Jeanne D’Arc Credit Union, not far from the 21st-century automobile traffic whizzing by on Lowell’s Father Morissette Boulevard.

When you walk into the coolly modern JDCU building, there’s little to indicate that the tunnels exist. The door that leads to them looks like it might open the way to shoulder-high stacks of century-old bank registers or dusty volumes containing the minutes of long-ago board meetings.

The remains of the Tremont Yard tunnels lie beyond that nondescript door. At one time, there was talk about converting the tunnels into a restaurant or a wine cellar. For lovers of history, thankfully, they remain as they were. As you pass through the doorway and stand among the aged fieldstone and brick, staring deep into the dark of the tunnels where light doesn’t quite reach, it’s easy to feel the present fall away for a moment, as if you have entered a time machine.

James Francis designed the tunnels as an experiment in the use of turbine power to run the mill that once stood on the floors above the powerhouse. Since the 1840s, Francis, chief engineer of a company called Proprietors of the Locks and Canals on Merrimack River, sought new techniques to increase the efficiency of water power.

These turbines were part of his grand experiment. In 1855, he published “Lowell Hydraulic Experiments,” a book on the subject. It went through numerous reprints, and the result of his work, the Francis turbine, remains the most widely used hydro turbine today. The largest hydropower station in the world, the Three Gorges Dam on China’s Yangtze River, uses 32 of them. Another famous example of where this Lowell-born technology helped revolutionize water power is Washington state’s Grand Coulee Dam, which uses 27 of the turbines.

If you were to return to Lowell during the Industrial Revolution, you would see a mill building where the JDCU offices now stand. That building, known plainly as Mill No. 2, included manufacturing space on its upper floors. The first story housed the turbines that were powered by water delivered by the tunnels. The building didn’t elicit much interest until 2007.

Ten years ago, the state, through Lowell Heritage State Park, hoped to revitalize and preserve the site by encouraging private development. Soucy Industries of Pelham, N.H., stepped forward and constructed a new building atop the historical foundation, preserving the tunnels.

To step into the Tremont Yard tunnels is to step back in time; they still smell of the damp fieldstone and bricks that have been there for 160 years. Thanks to JDCU, the Commonwealth of Massachusetts, and Soucy Industries, generations to come will enjoy the tunnels and continue to learn more about the history and heritage of Lowell. (Editor’s note: This story originally appeared in the May/June 2017 issue of Merrimack Valley Magazine.)

[ Updated April 15, 2020 ]

Jeanne D’Arc Credit Union

Lowell, Mass.

(978) 452-5001

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