Restoration Obscura Field Note
Hoosac Tunnel Ruins Mapping Project
West Portal Substation
Lat 42°40'33"N, Long 73°05'40"W/
This substation stands approximately 800 feet west of the Hoosac Tunnel’s western portal, just outside North Adams, Massachusetts. It was constructed in 1911 by the Boston & Maine Railroad as part of a tunnel electrification project designed to eliminate the buildup of smoke and gas inside the nearly five-mile-long bore.
The electrification system delivered 11,000 volts of 25-hertz alternating current to overhead catenary lines inside the tunnel. The power originated at the Zylonite generating station in Adams, MA, a steam-powered facility built specifically for this purpose. From there, transmission lines carried high-voltage current to this structure, where it was stepped down and distributed to electric locomotives operating exclusively within the tunnel zone.
These locomotives replaced steam engines through the tunnel itself, resolving decades of dangerous air quality issues. The system functioned from 1911 until the mid-1940s, when dieselization rendered it obsolete. The wires were dismantled, the locomotives retired, and the substations decommissioned.
Unlike the east portal infrastructure, this building survives as a complete, concrete-roofed structure. Inside, its steel support beams, brick-lined walls, and mounting points for transformers and switchgear remain visible. Along the upper edge of the interior, porcelain insulators, the distinctive “cowboy hat” style designed to shed water and prevent arc-over, were once bolted in place.
Immediately downslope from the site, Tunnel Brook runs parallel to the grade, following the historical alignment of utility lines and drainage systems associated with the tunnel’s western approach.
This is a surviving artifact of early 20th-century traction engineering. It represents a brief window when electricity replaced steam inside a mountain, and infrastructure was built to last, not be remembered.
Original images from the early-1900’s in the comments.
You can learn more about the troubled history of the tunnel and why it was nicknamed the Bloody Pit on Restoration Obscura and on the Restoration Obscura Field Guide Podcast.
www.restorationobscura.com
Hoosac Tunnel Ruins Mapping Project
West Portal Substation
Lat 42°40'33"N, Long 73°05'40"W/
This substation stands approximately 800 feet west of the Hoosac Tunnel’s western portal, just outside North Adams, Massachusetts. It was constructed in 1911 by the Boston & Maine Railroad as part of a tunnel electrification project designed to eliminate the buildup of smoke and gas inside the nearly five-mile-long bore.
The electrification system delivered 11,000 volts of 25-hertz alternating current to overhead catenary lines inside the tunnel. The power originated at the Zylonite generating station in Adams, MA, a steam-powered facility built specifically for this purpose. From there, transmission lines carried high-voltage current to this structure, where it was stepped down and distributed to electric locomotives operating exclusively within the tunnel zone.
These locomotives replaced steam engines through the tunnel itself, resolving decades of dangerous air quality issues. The system functioned from 1911 until the mid-1940s, when dieselization rendered it obsolete. The wires were dismantled, the locomotives retired, and the substations decommissioned.
Unlike the east portal infrastructure, this building survives as a complete, concrete-roofed structure. Inside, its steel support beams, brick-lined walls, and mounting points for transformers and switchgear remain visible. Along the upper edge of the interior, porcelain insulators, the distinctive “cowboy hat” style designed to shed water and prevent arc-over, were once bolted in place.
Immediately downslope from the site, Tunnel Brook runs parallel to the grade, following the historical alignment of utility lines and drainage systems associated with the tunnel’s western approach.
This is a surviving artifact of early 20th-century traction engineering. It represents a brief window when electricity replaced steam inside a mountain, and infrastructure was built to last, not be remembered.
Original images from the early-1900’s in the comments.
You can learn more about the troubled history of the tunnel and why it was nicknamed the Bloody Pit on Restoration Obscura and on the Restoration Obscura Field Guide Podcast.
www.restorationobscura.com
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