Daily Grind Opens Guilford
Rail to Double - Stack Traffic
Guilford Rail System is raising the roof for its range of services as it increases the height of the Hoosac Tunnel from 18 feet 3 inches to 19 feet 6 inches. This will allow Guilford Rail to handle covered tri-level auto carriers and double-stack intermodal container freight cars moving between New England and Chicago.
To accomplish this monumental task, specially designed grinders are being used to remove varying types of rock from the tunnel's roof. Upon completion of this project Guilford Rail will be able to expand its movement of double-stack traffic out of its brand new intermodal terminal in Ayer, MA (see page 12).
Approximately one year ago Guilford Rail's engineers began looking at different methods for accomplishing this project. From drilling and the use of explosives to using a mechanical device that is inserted into drilled holes and expands to split rock, many options were examined. "We chose the grinding method for the expediency, efficiency and the safety it offered us," said Project Engineer Phil Brake.
To accurately determine the volume of rock that needed to be removed from the tunnel, a laser survey was performed by Shannon & Wilson of Seattle, Washington and L-Kopia Laser Survey from Sweden. In one day over 20 million survey points were taken throughout the 4.75 mile long tunnel.
Spot grinding began on September 3 at the West portal of the tunnel. While necessary repairs and brick patch work have been done over the years, and a partial steel lining and insulation installed, the tunnel's width has remained unchanged since its original construction, completed in 1876.
Hardrock Tunnel Contractors of Las Vegas, Nevada were brought in for the job, with their special track-mounted 80,000 lb. grinding machines. Each machine is an excavator with a hydraulic unit mounted on the end of an arm that powers a 5-ton, cone-shaped grinder. Sensors tell the grinder's operator exactly where to cut on the uneven roof. The tunnel project will be followed by the undercutting, raising and reconstruction of 15 to 20 bridges early next year.
Depending on the density of the rock the project will take six to nine months to complete. Despite the massive amount of work needed to be done, Guilford Rail continues daily rail service through the tunnel, while allowing 10 uninterupted hours per day for Hardrock to grind.
"The Hoosac Tunnel is world renowned for both engineering accomplishments and failures during its construction," said Brake. "Another chapter in the history of this tunnel is being written and it is a distinct privilege to be a part of it."
According to Gerald Dale of Hardrock Tunnel Contractors, "Considering the history and fantastic accomplishments of the past to build this great tunnel, to be a significant part of its continuing evolution and growing importance to the railroad industry is an honor for us."
In the early days of the railroad, the Hoosac Tunnel was dug through a mountain in western Massachusetts to allow trains to go straight from Boston, through North Adams, to Albany, rather than take the existing route, now owned by Conrail, south through Springfield.
The project was begun in 1851 with a $2 million dollar grant from the Commonwealth of Massachusetts. Despite the large amount of funding for its day, the early stages of the project had more than their share of jagged edges. A steam-driven machine was to be the tool that would cut through the mountain in under a year. It never got further than 10 feet into the rock.
The engineers were forced to revert to using picks and hammers, and hand-blasting holes with black powder. By 1862, less than a mile of tunnel had been completed when the coupling of the Burleigh compressed-air drill and the discovery of nitroglycerin as an explosive gave project engineers the tools they desperately needed.
Finally, in late 1873, workers tunneling from east and west met beneath the mountain less than 1� inches off center from each other. Twenty five years, 650% over budget and almost 200 lives later, the first railroad car ran through the tunnel, in 1875. By 1900, dozens of trains were making the trip through the tunnel each day.