Trainz User ID: 124863
TS12 Build: 61388
T:ANE Build: 84356
www.hoosactunnel.net has a good history and modern pictures of the tunnel. Carl Byron's book "A Pinprick of Light" is more detailed with lots of historical references.
In summary the Troy and Greenfield or one of the early variants in the company name, under ownership of the Fitchburg Railroad, started building the tunnel in 1850s, and didn't finish the tunnel until 1875 with its final finishing completed in 1877. About 186 lives were lost in accidents and on the job with 13 falling to their death while constructing the central shaft. Many engineering practices were implemented during the construction which are now used in their modern form today. The earliest pneumatic drilling machine dug the "Little Tunnel" in North Adams then was sent to the east portal, about 8 miles away to drill through the hard rock. Instead the drill wasn't powerful enough and got stuck and remained in place for years afterwards until it was cut up for scrap. But... the drilling machine idea stuck and it was used later on with bigger and faster drills, which could break into the granite, basalt, schist and limestone.
Hermann Haupt, one of the great construction engineers and builders for the Pennsylvania Railroad, was hired on to build the line. The problem is the construction took so long the stakeholders got mad so the project was sold to the state. What was billed as costing about $3.5 million, ended up costing $25 million! Contractors mostly quit or were fired for not upholding the strict requirements for the work completion. The thing is because of the near bankruptcy of the project at the time, the Massachusetts Statehouse and governors then held the purse strings and dolled out tiny sums of money upon completion of the various sections.
The competing railroad to the south saw a drop of business once this tunnel opened so the Boston and Albany president paid off Governor Andrew to put up roadblocks to keep the project hamstrung. The engineers continued anyway, even put in their own funds, paying for the construction crews and equipment to the end. During this time, tri-nitroglycerine was put into use by Dr. Mowbray. Dr. Mowbray was an explosives engineer who determined the best positioning of explosives in a particular pattern to create the most effective blast. Nitroglycerine was used, but it was determined to be too unstable, however, it was discovered that when it was frozen it didn't explode until charged. They also tried dynamite, but it wasn't refined enough to be predictable or powerful enough. The Tri-nitro allowed for quicker building and the crews finally made progress. These blast patterns developed by Dr. Mowbray, are the same as those used today.
The engineers made use of conning towers to site plumb lines which were dropped through tiny shafts dug into the ground to the tunnel below. The crews below would use the plumb line plus the siting towers above which had lanterns in them as guide points to keep the tunnel in the proper path. When the tunnel opened, the two sides met only an inch or two off from the planned path. Not bad for 19th century technology. Today we use satellites and laser beams to guide the equipment through its bore.
The tunnel also was not built straight at grade and tips upward towards the central shaft from each direction. The grade, if I recall is 1/2 percent on each side. (It might be more or less, but I can't remember). The reason is to drain the constant water seepage out of the tunnels into cisterns and pipes and keep the tunnel dry.
The tunnel was initially opened as a double-tracked tunnel in 1875 with the final edifices placed on by 1877. From it's opening right through the early 20th Century, there were about 100 trains a day passing along the line. This caused way too much smoke in the tunnels and killed or severely injured crews and passengers. Because of the smoke, the central shaft was fitted with large blowers which were electrically powered. This helped, but it was not enough so when the B&M came under New Haven control during the early 1900s, the line was electrified. The electric service used big box motors (B&M class 5000s), which are similar to those used on the New Haven Railroad at the time. In fact the New Haven planned on electrifying the line as far west as Williamstown and as far east as Deerfield. The blowers were still used even with the electrics pulling the steam trains through the tunnel because of the stacks sending out noxious fumes. The same blowers, retrofitted with modern motors and updated in the 1940s, are still in use today.
The electric service lasted until 1946 when the motors, now quite elderly, having worked straight for 30-plus years, were replaced by diesels. In the 1950s the line was single-tracked through the tunnel, and in the 1970s the tunnel roof was raised to handle larger equipment. There are plans to do this again so container traffic does not need to be unstacked at Mechanicville for the trip east. Today the same line sees about 6 trains a day, which is a far cry from the nearly 100 per day when the tunnel first opened. Imagine a line with 100 trains a day!
When the tunnel opened, it was the longest railroad tunnel in the world, and stood as the longest tunnel in North America until the great tunnels in the Canadian Rockies and Cascade Mountains were built nearly 50 years later. What's really cool is much of the technology used in the tunnel construction was then improved and used today for the same purpose such as the big drilling machines and the guides and sighting towers, though we use lasers and satellites instead of rock piles with a wooden framework fitted with lanterns.
That's it for a quick summary!
Trainz User ID: 124863
TS12 Build: 61388
T:ANE Build: 84356
Thank for info about History !!
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