MEGA-Tunnels Of The WorldFor centuries, mountains and lakes posed massive problems for engineers. Like bridges, tunnels are a modern day engineering marvel, even though humans have been boring them for thousands of years.
In the past, we hewed tunnels out of massive rock faces with chisels and hammers; over the centuries, our methods have improved. Now, we bore tunnels with Tunnel Boring Machines (TBM), or “moles”, allowing us to dig deeper and farther than we ever have before.
As we mentioned, the longest tunnels are located in continents like Europe and Asia, but there are other modern marvels scattered across the globe as well. To give you the full picture on the longest rail and road tunnels to date, we’ve highlighted 10 of the longest (and impressive) tunnels in the world below.
Currently the longest and most expensive rail tunnel in the world, the Gotthard Base Tunnel opened for service on 11 Dec. 2016. Located 8,040 ft (2,450m) beneath the heart of the Gotthard axis in the Swiss Alps, the Gotthard Base Tunnel is the deepest railway tunnel to date and is used primarily to transfer both passengers and freight between northern and southern Europe.
Connecting the Japanese islands of Honshu and Hokkaido via the Tsugaru Strait, Seikan Tunnel lies 790 ft below sea level and is the longest tunnel in the world with an undersea passage. Designed for mass transit, construction of the tunnel lasted nearly 50 years, spanning from 1971 until its official opening in March 2016.
The Channel Tunnel is both a railway and shuttle transportation system connecting the UK and northern France. The undersea portion of the Channel Tunnel extends below the English Channel at the Strait of Dover, and has the longest undersea segment in the world at 23 mi (39 km). Construction for the Channel Tunnel began in 1988 and ended in 1994.
New Guanjiao Tunnel
The New Guanjiao Tunnel is a dual-bore, dual-rail tunnel extending across the Qinghai-Tibet railway in Guanjiao Mountain. The longest railway in China, it sits at 10,800 ft above sea level and took seven years to complete before it opened in 2014.
The Guadarrama Tunnel was built between 2002 and 2007 to shorten the travel time between Madrid and Segovia, two heavily trafficked tourist destinations separated by the Sierra de Guadarrama mountain range. Before the construction of the tunnel, which cuts directly through the mountains, travel time between the cities took well over an hour. Now, the tunnel services high-speed railway trains, reducing traffic time to thirty minutes.
The Laerdal Tunnel is a two-lane road tunnel connecting Laerdal and Aurland in Norway. The longest road tunnel in the world, it was built to replace ferry and mountain passage during the winter when traveling between Oslo and Bergen. The tunnel itself was designed with special neon lighting and limited straight sections to avoid wrecks and an overall feeling of monotony while passing through.
Kuala Lumpur’s SMART tunnel is the world’s longest multi-functional tunnel. It was designed to reduce traffic jams between Jalan Sungai Besi and Yoke Lew and to alleviate flash flooding throughout the city. A two-part tunnel, the SMART tunnel consists of a stormwater portion and a motorway portion. A complex engineering feat, construction on the tunnel took four years (2003 – 2007) and has already spared the city from over seven potentially dangerous flash floods in its city center.
Anton Anderson Memorial Tunnel
The Anton Anderson Memorial Tunnel is part of a greater network of tunnels and bridges located within the Chugach National Forest in Alaska. The Anton Anderson Tunnel is a single-lane highway that passes underneath Maynard Mountain, also a part of the Chugach Mountain Range.
Reaching a maximum elevation of about 11,160 ft, the Eisenhower Tunnel, located 60 miles outside of Denver, Colorado, is one of the highest vehicular tunnels in the world. Dual-bored with four lanes, it was one of the final major installments to the Interstate Highway system, and carries traffic under the Continental Divide in the Rocky Mountains.
Zion-Mount Carmel Tunnel
The Zion-Mount Carmel Tunnel was constructed in the 1930s to grant direct access to Bryce Canyon and Grand Canyon from Zion National Park. Built with mining techniques as opposed to traditional tunneling techniques, the tunnel’s dimensions are not large enough to accommodate multiple vehicles at once. Thus, drivers must pay a fee to transit the tunnel, and drivers of large vehicles (11 ft high, 7 ft wide) must give advanced notice before they are permitted passage.
While this is by no means an exhaustive list, we did our best to include the most talked about tunnels today.
The ground-fault circuit interrupter, or GFCI, is a fast-acting circuit breaker designed to shut off electric power in the event of a ground-fault within as little as 1/40 of a second. Electrical hazards are an area of major safety concern in most industries and account for a large number of injuries and fatalities. Extension cords and ground fault circuit interrupters (GFCIs) can be found on any construction site, shop, and jobsite as well as office buildings, warehouses and manufacturing plants. Remembering a few safety tips can help prevent serious injuries from happening.
A ground fault circuit interrupter can help prevent electrocution. If a person’s body starts to receive a shock, the GFCI senses this and cuts off the power before he/she can get injured. A “ground fault” is a conducting connection (whether intentional or accidental) between any electric conductor and any conducting material that is grounded or that may become grounded. Because of this potential for shock, GFCI protection is used to protect human life. It works by comparing the amount of current going to and returning from equipment along the circuit conductors.
It is recommended that GFCIs be installed in areas where appliances and power tools are used in close proximity to water. Tap water or wet objects are able to conduct electricity very easily and can connect your body to a ground potential, thus increasing your chances of receiving a shock from a ground fault. Appliances that have built-in GFCI protection, as now required for hair dryers, may not need additional GFCI protection, but there are still many appliances not equipped with GFCI protection. It takes only 5 mA (0.005 A) of current leakage from the hot wire to the ground to cause a GFCI to trip.
- From a small kitchen lobby in an office building to an industrial food plant, when using electrical equipment or extension cords near a water source they should be plugged into an outlet that is GFCI protected.
- When operating machine pumps, welding equipment, or other high energy producing equipment or tools, an industrial GFCI should be used.
- Always test GFCIs before use by using the test and reset buttons. If found defective do not use.
- Inspect all tools and equipment before use, if the ground pin is missing do not use it.