About the Cumberland Gap Tunnel

 

The Cumberland Gap Tunnel opened to highway traffic on October 18, 1996. The tunnels are located in the Cumberland Mountains of the Appalachian Range, where the states of Kentucky, Tennessee and Virginia converge.

Tennessee Portal

 

Pioneers such as Dr. Thomas Walker and Daniel Boone first discovered the “Wilderness Trail”, opening the western territory to settlers and pioneers. Cumberland Gap was known as the “Gateway to the West”. With the opening of the tunnel, the Cumberland Gap and the Wilderness Road were restored; and visitors are now able to gain the perspective of the early travelers. Modern technology has paved the way for restoration of the past.

Daniel Boone Parking Lot

 

The Cumberland Gap Tunnel uses a variety of technology to monitor, direct and respond to traffic. A control room operator watches several monitors in order to locate any potential problems which may arise outside or within the tunnels. The control room operator has direct contact with all employees and is able to control the variable message signs through the Vanguard Traffic Control System.

Tunnel Control Room

 

The tunnel is also equipped with a SCADA system (Supervisory Control and Data Acquisition System). SCADA monitors and controls the operation of ventilation fans, carbon monoxide gas monitors, smoke detectors and linear heat detectors, all located in the tunnel ceiling. SCADA alerts the control room operator of mechanical malfunctions within the buildings as well.

 

Operators are on duty 24 hours a day, seven days a week. All of the operators at the Cumberland Gap Tunnel are EMT certified and are able to respond to any emergency. Ambulances, Fire/Rescue trucks, and utility wreckers are located at each portal building.

 

 

 

Planning

 

The goal of the Cumberland Gap Tunnel project engineers was to facilitate safer travel along U.S. Route 25E, restore and preserve one of the nation's most historic routes, and to enhance recreational opportunities along the Gap.

 

A view from the top of the mountain on the existing highway before the Cumberland Gap Tunnel was constructed.

The 2.3-mile modern-day highway was constructed in 1916 and modernized in the 1960’s, however, by the 1950’s; it was obvious that the 2.3-mile crossing over Cumberland Gap linking Middlesboro, Kentucky to Cumberland Gap, Tennessee, had become a death trap. "Massacre Mountain" was one of the more popular and grisly nicknames, due to the number of motorists who lost their lives while traveling on the treacherous highway. Discussion of a tunnel under Cumberland Gap was first initiated by the National Park Service in 1956. During the next decade, studies were conducted that recommended a tunnel to improve the roadway without damaging the scenic and historic attributes of the Cumberland Gap.

 

During construction at the tunnel

In 1979, geologists examined exposed rock on the surface of the mountain and identified the various rock types. Next, a small-diameter horizontal core hole 2000-feet long, was drilled to provide even more geologic detail. Subsequently in 1985, a pilot tunnel, 10-feet high, 10-feet wide and 4100-feet long was excavated. This revealed many characteristics of the mountain that would later pose challenges to the Cumberland Gap Tunnel project. Thick clay infillings, limestone formations, caves and a lake were encountered. Numerous underground streams were a major challenge as well. Although Congress initially appropriated money for the project in 1979, the battle to improve the deadly U.S. Route 25E crossing, dragged on for two decades. An annual vote was taken on whether to continue paying for the design and construction of highway projects. At the urging of U.S. Representative Hal Rogers, a member of the House Appropriations Committee, the Cumberland Gap Tunnel project eventually became part of a highway budget that did not require annual reauthorization. Another boost to the project was the commitment of at least $2 million by the states of Kentucky and Tennessee to operate and maintain the finished tunnels.

 

 

 

Construction

 

A view of northbound portal on the Kentucky side during tunnel construction.

On June 21, 1991, construction began on the actual Cumberland Gap Tunnel project with the blasting of the northbound tunnel. This was one of the most important and expensive public works projects that was ever carried out in the state of Kentucky, as it replaced a narrow, deadly and winding road through the historic Cumberland Gap. By the time construction began, the two-lane route over the Gap was carrying twice as much traffic as it was designed to handle; and it had an accident rate six times higher than on similar federal highways.

 

On July 9, 1992, the two sides of the tunnel met in precise alignment in the center. The project was completed 1,947 days after the initial blast at a cost of $280 million. On October 18, 1996, a ceremony involving officials from Virginia, Kentucky and Tennessee celebrated the opening of the Cumberland Gap Tunnel.

The Kentucky portal during the Spring.

 

Seventeen years in the making, the Cumberland Gap tunnel project has spurred highway expansion in three states, hopes for tourism in small communities near the Gap, and dreams of restoring the wilderness trail that Daniel Boone blazed in the 1700s. The tunnel is "the most significant thing that has happened there since Daniel Boone began to bring settlers through the Gap."

- U.S. Rep. Hal Rogers

 

The tunnels, each carrying two-lanes of traffic, were bored through 4100-feet of solid rock. The tunnels, at the tallest point, are 30-feet high. Cross passages, located every 300-feet, connect the two tunnels and are equipped with fire extinguishers and phones for emergency use. Since the mountain releases approximately 450 gallons of water every minute, thick PVC liner around the tunnels ensures that the bores stay dry. Air quality is monitored constantly by electronic sensors, and ventilation fans are located every 600-feet to keep air circulating in the tunnel. Variable message board signs are located in the Cumberland Gap vicinity to warn drivers of impending hazardous traffic and weather conditions or to direct traffic flow. AM and FM radio stations can be overridden with emergency messages as well.

Looking north out of the southbound tunnel.

 

In addition, portal buildings at tunnel entrances house state-of-the-art ventilation, lighting and communications equipment, as well as closed-circuit cameras. Separate water storage tanks were constructed for use in the event of a fire in the tunnel. The Cumberland Gap Tunnel has dedicated fire, rescue and towing team’s on-duty 24-hours a day.

 

New road to the town of Cumberland Gap.

The project included five-miles of new four-lane approaches to the tunnels and two interchanges, one for the Cumberland Gap park entrance and another with US 58. Construction encompassed seven roadway bridges (four in Kentucky, three in Tennessee), a 200-ft. railroad steel box girder bridge, two pedestrian bridges on hiking trails, and three parking areas. An abandoned railroad tunnel under old U.S. Route 25E was repaired which later housed electrical, telephone, cable and water lines under the new U.S. Route 25E and US 58 interchange. Vehicular crossovers at tunnel entrances were constructed to allow for two-way traffic through the tunnel if one tunnel had to be closed.

 

The use of sandstone masonry, Cor-Ten weathering steel, concrete blended with earth-tone elements and the planting of many native trees help blend modern technology with the natural beauty of Cumberland Gap. As an offshoot of the Cumberland Gap Tunnel project, Kentucky completed U.S. Route 25E, a four-lane highway from Barbourville to Pineville. Tennessee also completed upgrades to U.S. Route 25E from Morristown to Harrogate.

 




Continue reading about restoring the gap...