A tunnel, known as a penstock, was built under Moderation Street (Bridge Street) in West Buxton to divert water from the Saco River to a new generating station.

The original Cumberland County Power Station was built in 1912 and enlarged in 1926. The new station, seen at the far end of the tunnel, was built to take advantage of unused water power capacity. The penstock allowed pressurized water to overflow into the river if the lower station turbine tripped off line. This protected the turbine and its gate from the sudden pressure.