The Great Northern Tunnel is a one-mile-long tunnel that runs beneath downtown Seattle from Alaskan Way (below Virginia Street) on the waterfront, to 4th Avenue S and Washington Street. The Great Northern Railway built it in 1904, at the insistence of Seattle City Engineer Reginald H. Thomson (1856-1949), to help alleviate rail congestion on Railroad Avenue (now Alaskan Way) and it is still in use today. In its heyday, the Great Northern Tunnel was the largest, although not the longest, tunnel in the nation. It cost $1,500,000 to build and was intended for use by both the Great Northern and the Northern Pacific Railroads, which split construction costs. Today the tunnel is owned and operated by the Burlington Northern -- Santa Fe Railway.
As Befits a Beautiful and Important City
The Great Northern Railway began service to Seattle from the East Coast in June 1893. The route the railroad chose crossed the Cascade Mountains northeast of Seattle through Stevens Pass (elevation 4061 feet), wandered through Snohomish County to Everett, entering Seattle from the north. The first Great Northern Depot was located at the foot (at about 2nd Avenue) of Columbia Street in a small clapboard building it shared with the Northern Pacific Railroad. The Seattle City Council complained that the facility was unbecoming of such a beautiful and important city and urged the railroads to build a much bigger and better passenger station.
Initially, James J. Hill (1838-1916), Great Northern's owner, wanted to build his terminals south of Jackson Street on a pier extending out over the tideflats so that cargo could be loaded directly on and off ships. The Great Northern operation in Seattle was to be the "Gateway to the Orient" with domestic goods sailing west and foreign goods traveling east by rail. The Seattle City Council rejected this plan because it would greatly increase the congestion and volume of train traffic on Railroad Avenue. The council gave Hill a piece of reclaimed tideflats south of Dearborn Street for his rail operations. Hill, wanting to be closer to the downtown business district, purchased the land between Dearborn and Jackson streets. He decided to build his new Great Northern Depot on 3rd Avenue between Jackson and King Streets. But first, Hill had to dig the promised train tunnel.
An Army of Workers
After a year of surveys and planning, construction of the Great Northern Tunnel finally began on April 4, 1903. An army of 350 workers with pickaxes, shovels, and wheelbarrows began digging into the hillside at a point between Western Avenue and, what was in 1903, Elliott Avenue and between Stewart and Virginia streets, the northern portal. Shortly thereafter, crews also started digging into the hillside at 4th Avenue and Washington Street, the southern portal. The engineers in charge of the excavation hoped to meet in the middle somewhere deep beneath the Seattle business district.
In the beginning, the miners encountered soft soil and the digging proceeded at 18 feet a day, a relatively fast pace. During the excavation, water seepage plagued the crews, mostly on the north end, which slowed progress. Periodically, the crews encountered dense blue clay and hard cement gravel formations which required drilling and further slowed progress down to 12 feet a day. At one point, 140 feet beneath the First Presbyterian Church at 4th Avenue and Spring Street, the miners discovered remains of a pre-historic forest, estimated to be at least 2,000 years old. Among the detritus, the excavation crew encountered a naturally preserved tree, more than three feet in diameter. After being exposed to the air, the tree slowly disintegrated into a mound of wood pulp.
A Historic Breakthrough
By October 13, 1904, the engineers estimated the advanced mining crews were only about 300 feet from each other. The digging continued day and night, each shift wanting to be the one to make the historic breakthrough. The crew in the north tunnel was about 60 feet west of 4th Avenue and 40 feet north of University Street. The crew in the south tunnel was working just below 4th Avenue at about Seneca Street. Both crews were working approximately 125 feet under the city. At their current rate of progress, the breakthrough was predicted for about November 5th.
But so intense was the rivalry between the day crew and the night crew that the two tunnels were connected on Wednesday, October 26, 1904. The day crew in the south tunnel encountered a pocket of soft dirt, enabling them to break through the last remaining foot of earth into the north tunnel at 5:55 p.m., just before the end of their shift. The breakthrough had been scheduled for about 10:00 p.m. but the day shift advance mining crew, in their enthusiasm to make history, and apparently without regard for established safety procedures, dug a man-sized hole through the wall. They immediately crawled through, meeting the advance mining crew in the north tunnel.
Still, the work was far from being completed. Workers removing loose debris from the core of the tunnel were still about 400 feet apart. According to all reports, the two tunnel shafts lined up almost perfectly, approximately 125 feet below ground under the Independent Telephone Company Building (now the Hotel Monaco) on the west side of 4th Avenue between Seneca and Spring streets. Two months later, the tunnel was complete in every detail and ready for train traffic. However, it was not used until the completion of the King Street Station in May 1906, another 17 months.
How It Was Done
So, how exactly was this tunnel constructed? The work was accomplished several ways. To begin with, an advance crew of expert miners tunneled ahead, making a shaft eight feet high and six feet wide at the designated roof line of the tunnel. Next, crews working about 100 feet back from the advance crew, dug debris from the sides of the tunnel, and made temporary walls of timber. The debris in the middle of the tunnel, known as the core, was removed last. As rapidly as the space between the core and dirt wall, known as drifts, was cleared, cement walls were installed. A temporary vaulted timber roof was also put in, to protect the crews removing the core debris. As soon as several feet of core debris was removed, a concrete floor, four feet thick, was poured and a permanent roof installed. Eventually the entire length of the tunnel was lined in concrete. The walls ranged from 5 1/2 feet thick at the bottom to 4 1/2 feet thick at the top. The vaulted roof ranged from 3 1/2 feet thick at the top to 4 1/2 feet thick where the roof met the walls. Great Northern engineers built, in every way, a quite substantial tunnel.
While under construction, the tunnel was illuminated with electric lights and ventilated with large electric fans. Small electric trains removed the loose dirt from inside the tunnel. Large electric shovels transferred the accumulated dirt to large gondola cars where it was transported to the King Street Station building site and used as fill. The excess fill dirt was used to level the future rail yard area, south of King Street.
A Great Engineering Achievement
In 1904, the Great Northern Tunnel, although not the longest, was the highest, 28 feet, and widest, 30 feet, in the United States. The finished tunnel was lighted by electricity, well ventilated and large enough to accommodate a double line of tracks. In constructing the tunnel, $1,000,000 was spent on labor alone and $500,000 was spent for materials and other costs. The tunnel was intended for use by both the Great Northern and the Northern Pacific Railroads, who split the cost of construction.
To complement this great engineering achievement, James J. Hill built the King Street Station, at a cost of $500,000, just south of the tunnel's southern portal. Construction of the depot began in December 22, 1904, and was completed and open for travel on May 10, 1906. The King Street Station, a large, beautiful, brick building in "Railroad Italianate" style was designed by the architectural firm of Reed and Stem, best known for designing the New York Central's Grand Central Station in Manhattan. The station has a magnificent clock tower approximately 245 feet tall, modeled after the tower at the Piazza de San Marco in Venice. Finally, Seattle had the grand railway station, which it deserved and of which it could be proud.
Today, the Burlington Northern -- Santa Fe Railway owns and operates the King Street Station and the Great Northern Tunnel, sharing the facilities with Amtrak. The northern portal of the tunnel can be seen from the public parking lot behind the Waterfront Landings Condominiums (1950 Alaskan Way, at the foot of Virginia Street). There is an excellent view of the southern portal from the overpass at 4th Avenue and Main Street and, affixed to the railing, a brass plaque commemorating the landmark.