For the full story of the Hoosac Tunnel’s construction, visit jkrails.net.
There were many problems connected with the construction of the Hoosac Tunnel. At the east end, progress was very slow. The black blasting powder of the day was no match for the hard, metamorphic rock. The west end’s soft, saturated soil would flow as soon as the miners scooped it. One worker likened it to “shoveling eels.” The east end was conquered by time and technology; the west end by backs and bricks.
It was finally decided that the best way to attack the West side of Hoosac Mountain was to dig a 500-foot-long trench, construct a brick invert “tub,” topped by a brick arch, forming a tube six to eight bricks thick, which was then backfilled with soil. Estimates are 20,000,000 bricks line the tunnel; all of them were made on-site.
Subsurface water was a major problem. The solution was to dig a series of wells along the tunnel line to monitor soil conditions and draw out huge volumes of water.
Mother Nature released a torrent on Sunday October 3, 1869. The storm was estimated to have dumped six inches of rain on the area. The natural brook that crossed over the tunnel (and still does today – Ed.) overflowed, and filled the tunnel with water, sand and rocks — behind the mining gang. Almost all of the miners reached the wells and climbed to safety. One man was lost to the torrents.
It took three weeks to remove the storm debris, but the brick tube survived in good shape. To further maximize drainage, engineers built flagstone drains outside of the tube, and inside just under the centerline below the tracks. Nonetheless, water clearly has been an ongoing problem for the tunnels West end up to the present day.
As the bore was extended into the mountain, logs were driven into the wet soil, and covered with boards to hold back the earth. The tube progressed for 883 feet to where soil stable enough to support the brick arch without the bottom invert, was found.