The Hoosac Tunnel (also called Hoosic or Hoosick Tunnel) is a 4.75-mile (7.64 km) active railroad tunnel in western Massachusetts that passes through the Hoosac Range, an extension of Vermont's Green Mountains. It runs in a straight line from its east portal, along the Deerfield River in the town of Florida, to its west portal, in the city of North Adams. Work began in 1851 under an estimated cost of $2 million and ended in 1875, having used $21 million. At its completion, the tunnel was the world's second-longest, after the 8.5-mile (13.7 km) Mont Cenis Tunnel through the French Alps. It was the longest tunnel in North America until the 1916 completion of the Connaught Tunnel under Rogers Pass in British Columbia. It remains the longest active transportation tunnel east of the Rocky Mountains, and as of 1989 is the sixth-longest railroad tunnel in North America. The American Society of Civil Engineers made the tunnel an Historic Civil Engineering Landmark in 1975. "Hoosac" is an Algonquian word meaning "place of stones".
Construction
Proposal and beginning
The tunnel project was originally proposed in 1819 as a canal to connect Boston to Upstate New York via the Deerfield River on the east of the Hoosac Range and the Hoosic River on the west. That project was shelved, and later reborn as part of the new Troy and Greenfield Railroad. The project was nicknamed "The Great Bore" by its critics, including future Supreme Court Justice Oliver Wendell Holmes Jr., who said that he would like to "wall up a dozen lawyers at one end of the tunnel and put a good fee at the other." The most important proponent of the northern route and the Hoosac Tunnel was Alvah Crocker, a self-made paper mill owner from Fitchburg, Massachusetts. The project was promoted by Crocker but mostly organized and engineered by others, notably Herman Haupt in the early stages, and several other firms under contract, under the direction of several head engineers assigned by the state of Massachusetts, which took over the project after it initially failed and went bankrupt. In 1841, Crocker formed the Fitchburg Railroad (chartered 1842, opened 1845) between Boston and Fitchburg. In 1844, Crocker incorporated the existing Vermont and Massachusetts Railroad, which ran from Fitchburg west to Greenfield, as well as northward (from Millers Falls) to Brattleboro, Vermont. In 1848, Crocker secured from the legislature a charter for the Troy & Greenfield Railroad (T & G), with provisions for a tunnel through Hoosac Mountain. The first chief engineer of the tunnel project was A.F. Edwards. In 1854, the Commonwealth of Massachusetts provided $2,000,000 (equal to $71,666,667 today) in credit to Edward Wellman Serrell and Company, which began work in 1855. In 1856, Herman Haupt took over as chief engineer. The Western Railroad, led by Chester W. Chapin, which ran a southern route through Springfield and Pittsfield, opposed the Hoosac Tunnel and its northern route through the state. It successfully lobbied to block state funding of the tunnel in 1861, which bankrupted Haupt and temporarily stopped the project. Haupt had excavated 4,250 feet (1,300 m), or about a fifth of the distance, at that point. He left and became a Union Army railroad engineer and general in the American Civil War.
Completion
In 1862, the Troy and Greenfield Railroad defaulted on its loan from the Commonwealth of Massachusetts, which foreclosed on the mortgage and took control of the railroad, including the tunnel project. The state sent engineer Charles Storrow to Europe to study modern tunneling techniques, including the use of nitroglycerin and compressed air. In 1863 the state, with Alvah Crocker now superintendent of railroads, restarted the project and made Thomas Doane the chief engineer. In 1868, the Massachusetts state legislature appropriated $5 million to complete the project. Canadian engineer Walter Shanly (sometimes spelled Shanley) and his brother Francis took over the project from the state and remained through the completion of the tunnel boring. Among the consulting engineers at the time was Benjamin Henry Latrobe II, a noted civil engineer who was serving as the chief engineer of the Baltimore and Ohio Railroad. The final chief engineer was Bernard N. Farren, who took over on November 19, 1874, and on Thanksgiving Day that year, the last 16 feet (4.9 m) of rock was removed beneath the town of North Adams. Farren completed the work, including enlarging sections of the tunnel, reinforcing weak areas with arching, completing drainage systems and completing the east tunnel facade. The first train passed through the tunnel on February 9, 1875.
Technology
The tunnel construction project required excavation of 2,000,000 tonnes (2,000,000 long tons; 2,200,000 short tons) of rock. On March 16, 1853, "Wilson's Patented Stone-Cutting Machine" (a tunnel boring machine) was used; it failed after excavating 10 feet (3.0 m) of rock. Tunnel builders resorted to hand digging, and later used the Burleigh Drilling-machine, one of the first pneumatic drills. Construction also featured the first large-scale commercial use of nitroglycerin and electric blasting caps and the first such use in the United States. Digging the Central Shaft also allowed workers to open two additional faces to excavate: once the shaft was completed in 1870, workers dug outwards from the center to meet the tunnels being dug from the east and west portals. Engineers built a 1,000-foot (300 m) elevator to hoist the excavated rock from the Central Shaft. One of the many engineering challenges posed by the project was getting the proper alignment between the four tunnel segments that were being dug: the east and west portal tunnels and the two tunnels dug outward from the central shaft. Engineers cleared a path through the forest over the mountain and strung a straight line from the east to west portals through "sighting posts" on the east and west peaks of Hoosac Mountain. In 1866, Thomas Doane took over as chief engineer. He resurveyed the alignment of the tunnel by constructing six towers.
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