Lieutenant William F Callahan Tunnel (MA 1A)

This 2005 photo shows the rebuilt northbound approach to the Callahan Tunnel in the North End of Boston. The tunnel approach was rebuilt in conjunction with the Central Artery (I-93) tunnel project. (Photo by Jim K. Georges.)

Construction started:     
Opened to traffic:     
Number of tubes:     
Number of traffic lanes:     
Length between portals:
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Operating headroom of tunnel:     
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Maximum depth, mean high water to roadway:
Number of fans (original configuration):   
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April 30, 1959
November 11, 1961
1 tube
2 lanes (northbound)
5,650 feet (1,545 meters)
1,500 feet (457.2 meters)
12 feet, 6 inches (3.8 meters)
30 feet, 98 inches (9.3 meters)
90 feet (27.4 meters)
12 fans
$29,000,000 (including approaches)

Passenger car EZ-Pass toll (southbound):
Passenger car pay-by-plate toll (southbound):

$1.50
$2.05

Hazmat and height restrictions apply.

A STORY THAT PREDATES THE SUMNER: Plans for a second vehicular tube underneath Boston Harbor actually predated construction of its older companion, the Sumner Tunnel. In 1920, engineers proposed a "teaming tunnel" that featured a dual-tube design, with each tube accommodating two lanes of vehicular traffic.

The early tunnel design appeared to incorporate the same emerging ventilation concepts being developed by Clifford Holland for the Hudson River Vehicular Tunnel (later renamed the Holland Tunnel [I-78]) in New York. Holland's revolutionary two-duct system utilized one duct to draw in fresh air and another to expel exhaust air, a design eventually adopted by vehicular tunnels worldwide.

To facilitate the exchange of clean and dirty air, the team developed a system of ventilator fans and airshafts to circulate clear air throughout the length of the tunnel. Helical approaches were planned to connect the tunnel with the local street networks in Boston and East Boston. The twin-tube tunnel was estimated to cost $10.7 million.

Planners and politicians debated through the mid-to-late 1920s whether a four-lane suspension bridge or a single-tube, two-lane tunnel should be built across Boston Harbor. Even the Massachusetts Division of Metropolitan Planning, which favored the single-tube alternative due to its lower estimated cost ($9 million for the single-tube tunnel alternative versus $16 million for a suspension bridge alternative) acknowledged that a second two-lane tube would be necessary before 1940.

Construction of the Sumner Tunnel began on March 30, 1931. The tunnel was opened to traffic on June 30, 1934. For the first time, motorists were able to travel directly from Downtown Boston to Logan Airport in just five minutes.

However, the idea of a second harbor tube did not disappear with construction of the Sumner Tunnel. By the waning days of World War II, rapidly increasing traffic through the existing tunnel and anticipated growth at Logan Airport revived plans for a second crossing.

DEMONSTRATING THE NEED FOR A SECOND TUNNEL: In April 1945, during the waning days of World War II, engineers began exploring a potential second harbor tunnel alongside the existing Sumner Tunnel. The tunnel was running at its 23,000 vehicle-per-day capacity - and slightly over peak capacity during the summer - prior to the start of World War II. Engineers projected the volumes in the Sumner Tunnel would reach 30,000 per day immediately after the war and 45,000 per day before 1965, with airport traffic comprising nearly 20% of total traffic.

In addition to building a second harbor tube, engineers also recommended building the following routes through East Boston:

  • A six-lane tunnel from the Sumner Tunnel (and parallel tunnel) approach northeast towards McClellan Highway. This was the genesis of what was to eventually become the elevated East Boston Expressway (former Route C1, now MA 1A), which was the first controlled-access freeway within Boston city limits.

  • A four-lane elevated highway connecting the Sumner Tunnel (and parallel tunnel) approach with Logan Airport. The highway, which was to be routed along Maverick Street was never built in that form, though additional access would come decades later with the construction of improved approaches in the 1990s as part of the Ted Williams Tunnel (I-90) project.

After nearly three years of discussion and debate, the Massachusetts Department of Public Works (MassDPW) submitted a 10-year, $356 million Master Highway Plan for the Boston Metropolitan Area to Governor Robert Bradford. The ambitious plan called for the construction of 87 miles (140 kilometers) of new expressways, along with second Boston Harbor tunnel and a new bridge over the Mystic River.

The Boston Globe described the route of the parallel tunnel as follows:

"The proposed second traffic tube to East Boston would be located on Atlantic Avenue opposite Clinton Street, and a branch at Richmond Street and Atlantic Avenue. The tunnel would connect with the present tube. This arrangement would enable two-way traffic in either of the tubes should one or the other become blocked."

The Globe also described the connections to the proposed East Boston Expressway in East Boston and the elevated Central Artery in Boston as follows:

"An express highway would carry the traffic from the tunnel exit in East Boston to the present high-speed highways connecting with main arteries to the North Shore and the Newburyport Turnpike. At its Boston exits, the vehicular traffic would connect with the proposed Central Artery and the Belt Route."

In 1951, Governor Paul Dever, who oversaw parts of the state's postwar highway construction program - including the Central Artery, Route 128, and Storrow Drive - asked the State Legislature to approve what The Boston Globe called the "biggest single construction job" in the second harbor tunnel. The governor did not provide a cost estimate, but engineers advised the Massachusetts Department of Public Works (MassDPW) that construction would cost between $25 million and $30 million. While the governor cited congestion relief as a key benefit of its construction, he pulled on Cold War-era sentiment to cite its potential use as a bomb shelter.

This 1959 photo shows preliminary construction underway at the East Boston portal for the Callahan Tunnel. (Photo from the Boston Public Library archives, www.bpl.org.)

VOLPE MAKES THE CASE, BUT A LOGJAM ENSUES: In 1954, John Volpe, the state's public works commissioner who later served as governor and then as U.S. secretary of transportation under President Richard Nixon, presented his case for the second harbor tunnel before the House Ways and Means Committee. At the time, plans for the second tunnel were one-third complete, and Volpe requested additional funds so that construction could start by 1959.

Even as Volpe presented his case, some officials and business leaders voiced their opinion that a new bridge, which would have as many as six lanes, was a better solution; however, as was the case a quarter-century earlier, objections were raised not only over potential costs (as much as $80 million for a six-lane bridge), but also the high clearances required for the bridge that were incompatible with normal operations at nearby Logan Airport.

With progress at a standstill, Governor Christian Herter appointed a five-member committee - with Volpe serving as chairman - to study the viability of a tunnel or bridge, as well as the potential consolidation of the Sumner Tunnel, Mystic River (now Tobin) Bridge, and new crossing under a single authority.At the time, the Sumner Tunnel was operated by the City of Boston, while the Mystic River Bridge was operated by the state-owned Mystic River Bridge Authority.

The postwar bridge proposal faded, but by 1957, some doubts emerged about whether the Massachusetts Port Authority (Massport), which now had jurisdiction over the Mystic River Bridge, the Sumner Tunnel, and the proposed parallel tunnel, would build the new tunnel. Over the objection of Boston Mayor John Hynes, Massport said it favored a connection between the Mystic River Bridge and the proposed Inner Belt Expressway (unbuilt I-695) before a second tunnel was built. With President Dwight Eisenhower having signed the Interstate Highway Act into law the previous year, some state officials sought 90 percent federal funding for improvements to the Sumner Tunnel and construction of the new parallel tunnel, even as the project remained at an impasse with Massport.

BREAKING THE LOGJAM: On October 17, 1958, the Boston City Council voted unanimously on a proposal to allow the Massachusetts Turnpike Authority to take over jurisdiction of the Sumner Tunnel and construction of the new parallel tunnel, in exchange for a $10 million payout to the city. William F. Callahan, the Chairman of the Turnpike Authority, said construction would begin within 18 months of the transfer.

The new tunnel was to be built 50 to 100 yards (45.7 to 91.4 meters) east of the existing Sumner Tunnel. Upon completion, the new tunnel would carry northbound (East Boston-bound) traffic, while the Sumner Tunnel would carry southbound (Boston-bound) traffic. Callahan emphasized that the new tunnel - while built and operated by the Turnpike Authority - would be an "absolutely separate entity" from the turnpike itself, whose extension from Weston to Boston was being planned at the time.

The Turnpike Authority floated a $42.8 million revenue bond issue for construction of the new tunnel. It also issued a separate $10 million bond issue for the authority to purchase the Sumner Tunnel from the City of Boston. With financing now in place and a single authority overseeing both facilities, the long-discussed second tunnel project finally moved from the planning stage toward construction.

This 1961 photo shows construction of the concrete roadway slab inside the Callahan Tunnel. (Photo from the Boston Public Library archives, www.bpl.org.)

"We're right on schedule� Unless we run into something which will cause a big delay, we should have the tunnel built by the target date in December 1961." - Irving R. Huie, project manager of the Callahan Tunnel project in a 1959 Boston Globe interview

BUILDING THE TUNNEL: The ceremonial groundbreaking for the second tunnel took place on April 30, 1959. Actual excavation began soon afterward from both the Boston and East Boston sides, with crews driving toward the middle of Boston Harbor. Irving R. Huie, the project's chief engineer and project manager, was just 30 years old when construction began. Huie later managed construction of the Massachusetts Turnpike (I-90) extension from I-95 / MA 128 (Yankee Division Highway) in Weston east to I-93 / US 1 / MA 3 (John F. Fitzgerald Expressway / Central Artery) in Boston.

Like the Sumner Tunnel nearly three decades earlier, the new tunnel was built using the tunneling shield method in which a cylindrical protective shield was used to bore under Boston Harbor while shielding workers from collapse and water ingress. This method was used for the 4,800-foot (1,463-meter) distance between the portal transitions, while the Boston and East Boston landside approaches to the tunnel were built using a more traditional cut-and-cover method.

The shield, which measured 32 feet (9.8 meters) in diameter, was a complex arrangement of hydraulic rams, muck diggers, davit arms, and power tools. It was hydraulically propelled and had sliding steel bulkheads at the heading to support loose material. The 28 hydraulic rams, which supported the heading during excavation, were each capable of exerting a force of 200 tons (181.4 metric tons) and could advance the shield four feet (1.2 meters) with each shove before work proceeded to the next section.

A conveyor belt system was designed to remove 134,000 cubic yards (102,450 cubic meters) of spoil and sediment from the shield through the completed sections of tunnel to the surface, where the material was transported by truck off-site. Much of the excavated material was transported to Patten's Cove along Morrissey Boulevard, where the Metropolitan District Commission (MDC) used the fill to reclaim portions of the tidal marsh for recreational use.

NAMED AFTER A WAR HERO: In early 1960, the tunnel was named after Lieutenant William F. Callahan, Jr., the son of the Turnpike Authority chairman. The younger Callahan was a 1943 graduate of Pennsylvania Military College who served in the 85th Mountain Infantry Regiment of the 10th Mountain Division. He was killed in the mountains of northern Italy just days before the end of World War II in 1945.

SANDHOGS SAVE THE DAY: Around the clock, every day except Sunday, a work crew comprising 45 workers, or "sandhogs," descended into airlocks to work under Boston Harbor. The sandhogs worked in a high-pressure chamber that was the equivalent of 1.7 atmospheres, or 1.7 times the normal air pressure found at sea level.

The skill and courage of the sandhogs were tested on the afternoon and evening of July 2, 1960, when high pressure blew a hole through 35 feet (10.7 meters) of the harbor floor, flooding the tunnel with as much as nine feet (2.7 meters) of water.

From the Boston Globe account of the break:

As the pressure fell with the escape of air, the water began to pour through the now-gaping hole. Only the onslaught of debris hurled by the 45 sandhogs prevented disaster.

One sandhog told the Globe that the sandhogs "threw everything" at the gaping hole, while another added that "if we could have found a dead rat, we would have stuffed it in too."

NOT MISSING A STEP: Despite the incident, construction of the tunnel continued on schedule. On March 30, 1961, less than nine months after the tunnel breach incident, the tunneling shield removed the last of the spoil and sediment beneath Boston Harbor. The tunnel's primary liner is high-strength steel; the concrete infill of the final liner is 9.8 inches (25 centimeters) thick.

Once the steel and concrete linings were completed, work began on bringing the tunnel to its final form. The concrete roadway slab, which accommodates two lanes each traffic (each lane 12.1 feet or 3.7 meters) wide, is supported by steel floor beams measuring 29.5 inches (75 centimeters) wide at the center (widest point). Lights and traffic signals were also installed.

While the sandhogs worked below to connect Boston to East Boston, other crews worked above to build the tunnel's two 118-foot (36-meter) ventilation towers in Boston and East Boston. Each ventilation tower had six fans, three for fresh air and three for exhaust air; the fans were made slightly larger for the East Boston tower to accommodate the additional exhaust generated by vehicles climbing the incline toward East Boston. A combination service building and maintenance facility was also built in East Boston.

THE TUNNEL OPENS: On November 11, 1961, a little over 30 months after the groundbreaking and one month ahead of schedule, the $29 million Callahan Tunnel was opened to traffic.

Immediately after the Callahan Tunnel was opened, work began on a seven-month project to modernize the Sumner Tunnel. Work included repairing the concrete ceiling, repaving the roadway with a new asphalt pavement, replacing tiles that had become weakened during freeze-thaw cycles, and installing new lighting. During this period, the Callahan Tunnel assumed two-way operations. As part of the modernization program, the Turnpike Authority also purchased two motor-driven wall washers to clean the tunnels overnight. Upon completion of the Sumner Tunnel modernization project on June 15, 1962, a long-sought goal had been achieved: four lanes of traffic under Boston Harbor through dual two-lane tubes.

While the Sumner Tunnel was undergoing renovations, the initial toll on the Callahan Tunnel was 20 cents. The toll was raised to 25 cents for both the Sumner and Callahan Tunnels

This 1961 photo shows construction nearing completion at the Boston portal for the Callahan Tunnel. (Photo from the Boston Public Library archives, www.bpl.org.)

A NEW CEILING AND REFURBISHED ROADWAY: In 1989, nine vehicles were damaged by falling ceiling tiles. Engineers attributed the failures to daily tunnel washings and accumulated diesel exhaust, which combined to create mild sulfuric and carbonic acids that attacked the mortar and caused the ceiling tiles to debond.

Once funding was secured for repairs in 1990, work began the following year on replacing the six-inch (15-centimeter) cast-in-place ceiling. During preliminary demolition, engineers discovered that soot above the ceiling contained lead deposited by the combustion of leaded gasoline. This would have classified the concrete demolition debris as hazardous material, potentially increasing disposal costs by more than 300 percent. To avoid the additional expense, ceiling work was suspended for a month while crews power-washed and vacuum-cleaned the contaminated surfaces before the material was moved off-site.

The new ceiling consisted of more than 3,000 porcelain-coated encapsulated steel panels with a fire-retardant infill. To expedite construction, the new ceiling was installed at a rate of 100 to 130 feet (30 to 40 meters) per work shift, approximately 165 feet (50 meters) behind demolition of the old ceiling.

While work on the ceiling was underway, engineers also repaired extensive deterioration beneath the roadway. The roadway slab and tunnel liner around the fresh air duct had deteriorated severely from road salts carried into the tunnel by passing vehicles. When the salts mixed with tunnel drainage water, the resulting chloride attack had, in some locations, reduced the concrete to gravel. Because the tunnel was available for construction for only six and one-half hours each night, the chief project engineer worked with a manufacturer to develop a rapid-setting, high-strength, polymer-modified shotcrete (concrete or mortar projected at high velocity onto a surface) that achieved its initial set within 20 minutes.

After a year of overnight and weekend construction, the Callahan Tunnel rehabilitation project was completed on July 29, 1992, at a cost of $8.5 million.

A NEW AGENCY: In July 2009, Governor Deval Patrick signed the "Act Modernizing the Transportation Systems of the Commonwealth" into law. The Act, which became effective at the end of 2009, enabled the creation of a new Massachusetts Department of Transportation (MassDOT), which consolidated the operations of the Massachusetts Turnpike Authority (which operated the Sumner and Callahan Tunnels), the Massachusetts Port Authority (which operated the Tobin Bridge), the Massachusetts Department of Highways, and the Registry of Motor Vehicles into a single state agency.

AND NEW WALL PANELS: The second major rehabilitation of the Callahan Tunnel, and the first one under MassDOT ownership, took place in 2013-2014, when a $35 million project began to replace the tunnel's more than 2,800 wall panels, as well as rehabilitate the tunnel's deck, curb line, and gutters. Prior to the project, engineers removed 123 deteriorated wall panels in December 2012 after one panel fell onto the roadway (there were no injuries), and in January 2013, engineers removed the remaining wall panels. The tunnel was closed completely for three months from December 2013 through March 2014, with weekend and overnight closures continuing through August 2014.

According to MassDOT, the Callahan Tunnel carries approximately 40,000 vehicles per day (AADT).

These photos were taken during the 2013-2014 rehabilitation project on the Callahan Tunnel (MA 1A). (Photo credit: BridgePreservation.com / PPG Industries.)

SOURCES: "Recommends Four-Way Teaming Tunnel Between City Proper and East Boston, The Boston Daily Globe (1/30/1920); "Another Tube in East Boston Tunnel" by Louis M. Lyons, The Daily Boston Globe (4/11/1945); "Second Tunnel Features Compromise Traffic Plan" by John G. Harris, The Daily Boston Globe (4/23/1947); "Relief for Boston Seen Waiting on Traffic Analysis, The Daily Boston Globe (9/10/1947); "Plan Eight Boston Speed Highway," The Daily Boston Globe (2/15/1948); "Navy Would Oppose Bridge Across Harbor, Legislators Told," The Daily Boston Globe (3/17/1948); Master Highway Plan for the Boston Metropolitan Area, Massachusetts Department of Public Works (1948); "Politics and Politicans: Second Toll Tunnel Biggest Construction Job Asked by Dever" by John G. Harris, The Daily Boston Globe (1/14/1951); "At the State House: Another Tunnel Needed by '59, Says Volpe, The Daily Boston Globe (2/02/1954); "Our Underwater Traffic Jam" by K.S. Bartlett, The Daily Boston Globe (1/16/1955); "New Authority Would Build Second Auto Tunnel" by William J. Lewis, The Daily Boston Globe (6/23/1955); "US Help Possible in Building Second Tube to East Boston," The Daily Boston Globe (6/07/1957); "Senator Hennigan Seeks Second Harbor Tunnel," The Daily Boston Globe (2/26/1958); "Port Issue Airing Due Wednesday" by Joseph A. Keblinksky, The Daily Boston Globe (4/13/1958); "House Favors Tunnel Shift" by S.J. Micciche, The Daily Boston Globe (5/22/1958); "Council Clears Way for Second Harbor Tube" by Joseph A. Keblinsky, The Daily Boston Globe (10/18/1958); "Work Due To Start in June on Second East Boston Tunnel," The Daily Boston Globe (4/10/1959); "Ground Broken in East Boston for Second Tunnel," The Boston Globe (5/01/1959); "Huie Directs Work on Second Harbor Tube" by Robert B. Carr, The Daily Boston Globe (12/05/1959); "New Harbor Tunnel Grows by 16 Feet a Day" by Lawrence E. Ryan, The Boston Globe (2/19/1960); "Mud from New Tunnel Builds MDC Playground" by Earl Banner, The Boston Globe (4/08/1960); "'We Mine Down Muck, Move Shield, and Put Up Iron'" by Paul Benzaquin, The Boston Globe (5/22/1960); "Sea Pours into New Hub Tunnel, Sandhogs Win 6-Hour Battle To Save It" by Mark Feinberg, The Boston Globe (7/03/1960); "Callahan Tunnel To Be Ready by November" by Lawrence E. Ryan, The Boston Globe (2/22/1961); "Digging Crews Complete Tunnel Break-Through," The Boston Globe (3/31/1961); "Second Tube Tunnels Along," The Boston Globe (4/30/1961); "Giant 'Squirrel Cages' Ready as New Boston Tube Nears Opening Day" by A.S. Plotkin, The Boston Globe (9/10/1961); "Speakers Praise Both Callahans as Ribbon Cutting Opens Tunnel" by Edward McGrath, The Boston Globe (11/12/1961); "Tunnel Was Team Job of Many Skills," The Boston Globe (11/12/1961); "Sightseers Tie Up Tunnel," The Boston Globe (11/13/1961); "Ask the Globe," The Boston Globe (5/06/1989); "State Panal OKs Bond Measure To Refurbish Two Tunnels" by Ronald Rosenberg, The Boston Globe (4/26/1990); "Officials Say Renovation of Callahan Tunnel Done" by Brian Bishop, The Boston Globe (7/30/1992); "Rehabilitation of the Sumner / Callahan Tunnels" by Henry A. Russell, Jr., Concrete Repair Bulletin (May-June 2002); "Tunnel Visions: Big Dig Tragedy Puts Onus on Boston's Old Reliables" by Mac Daniel and Ari Bloomekatz, The Boston Globe (7/16/2006); "Big Dig Report: Sumner, Callahan Tunnels Have Problems" by M.R.F. Buckley, WCVB-TV (9/26/2006); "Two Boston Tunnels Require Repairs" by Katie Zezima, The New York Times (9/27/2006); "Irving Huie, 78, Led Project To Build Callahan Tunnel" by Peter J. Howe, The Boston Globe (8/07/2007); "Boston's Callahan Tunnel Set for Three-Month Rehab Closure" by Johanna Knapschaefer, Engineering News-Record (7/02/2013); "Moving Ahead in the Shut-down Callahan Tunnel" by Martine Powers, The Boston Globe (1/08/2014); "Callahan Tunnel Set To Reopen for Monday Morning's Commute" by Steve Annear, Boston Magazine (3/07/2014); BridgePreservation.com; Island Pavement Cutting; Massachusetts Department of Transportation.

  • MA 1A shield by Barry L. Camp.
  • Lightposts by Millerbernd Manufacturing Company.
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CALLAHAN TUNNEL LINKS:

CALLAHAN TUNNEL CURRENT TRAFFIC CONDITIONS:

CALLAHAN TUNNEL VIDEO LINKS:

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