Nick's Lists Follow Up: Tunnels

After the success of my series on bridges for the last few days, I feel it appropriate to do a short follow up list on tunnels.  Again, as with the bridges, I am focusing on tunnels in America.  The criteria for making this short list is essentially the same as the bridge list: engineering quality, importance in the highway network, historical significance, an aestethics.  Obviously since tunnels are not quite as spectacular to look at, the aesthetics factor is not quite as important as it is with the bridges.  That being said, I am not going to do an official ranking of these tunnels.  This is just a list of some of my favorite tubes that I have either driven through or watched videos and seen pictures of on the Internet.  So let's take a look.  Hope you enjoy it. 

Fort McHenry Tunnel: I-95 under Baltimore Harbor, Baltimore Maryland
Length 1.5 Miles
Toll-$2

I find it odd that the MdTA website calls the Fort McHenry Tunnel the "final" link in I-95, considering it is still incomplete.  Nevertheless, the "Baltimore Bottleneck," as it became to be known, was a major choke point in the trip from Washington to New York for years as there was no fixed crossing over the harbor.  Traffic had to empty onto Baltimore's already crowded downtown streets, adding hours to a trip that is long enough already.  The opening of the Harbor Tunnel in 1957 eased some of the stress, but as populations grew, and traffic counts grew, the 4-lane Harbor Tunnel just could not handle the load, and the Baltimore Bottleneck returned.  Baltimore serves almost as much through traffic as it does commuter traffic, and both use the same main drags.  The Key Bridge is a little bit out of the way, but it is a nice little drive with not a lot of company.  The Fort McHenry Tunnel can claim itself to be the widest underwater submerged-tube tunnel in the world, as it is the only tunnel with dual tubes in each direction for a total of 8 lanes of traffic.  When this tunnel opened in November 1985, that officially marked the day the old Baltimore Bottleneck died.  Baltimore still has its fair share of choke points, but I no longer count the harbor as one of them. 

Anton Anderson Memorial Tunnel: Portage-Glacier Highway through Maynard Mountain, Whittier, AK
Length: 2.5 miles
Toll: $12

Ah yes, the old Alaskan Tunnel to Nowhere, or was that supposed to be a bridge?  Actually, this is a tunnel to somewhere, Whittier as a matter of fact.  On top of that, the good folks in Whittier now have a direct automobile route to get to Anchorage by way of the Seward Highway.  This is a converted railroad tunnel dating from World War II, and it's not totally converted.  The way this thing runs is weird.  There is only one lane in the tunnel and it's shared with the railroad track.  A computer system directs traffic from both directions in and out of the tunnel.  While vehicles wait their turn, they have to park in a "staging" area on both sides of the tunnel, while they wait for the other direction of traffic to empty out.  Trucks and large vehicles always go last so that (according to the website), in the event of an accident there are the fewest number of people possible in the tunnel.  The tunnel also closes in 15 minute intervals, and through the duration of the night, so that the Alaska Railroad can use the track.  The conversion to an auto-ready road, detailed here, explains that the existing one-lane railroad tunnel was chosen (as opposed to a brand new tunnel) as it would save tens of millions of dollars in construction costs.  However, more rock had to be excavated and the road bed completely rebuilt, as well as installing ventilation systems and safety escapes.   I know that I said aesthetics would not play a huge role in this list, but this is amazing.  The portals look like the entrance to a mine shaft and the inside of the tunnel is just freaky looking.  Check it out.



Portal House-Taken from dailyventure.com



Tunnel Interior.  Notice the railroad track on the road bed.  Taken from Wikimedia Commons courtesy of Mark Fickett

Chesapeake Bay Bridge Tunnel: US 13 over mouth of Chesapeake Bay, Cape Charles and Virginia Beach, VA
Length: 20 miles
Toll: $12 (24 hour return trip with receipt is only $5)

This is one of the Seven Engineering Wonders of the World, and has won numerous other awards.  I've seen it.  I have not actually driven it, but I've seen it.  For decades, the Eastern Shore of Virginia (Accomack and Northampton Counties) were splendidly isolated from mainland Virginia by way of the Chesapeake Bay.  In order for residents to go to the rest of the state, they had to go up through Maryland and back down Route 40 by the Hatem bridge, creating even more of a hassel than for Maryland residents going to and from Ocean City.  The opening of the Chesapeake Bay Bridge in Maryland made life tons easier for Maryland residents, but didnt' really do much for Eastern Shore Virginia residents (although that cut at least 3 hours off the drive to Richmond).  Bridge-tunnel technology had already been in place in Southern Virginia for a few years prior to the opening of the CBBT.  The I-64 Hampton Roads Bridge Tunnel (HRBT) was the first of its kind.  It was necessary because engineers wanted a low profile for the bridge, yet at the same time allow ocean going vessels to reach the ports of Norfolk and Newport News, as well as the Naval Station (the largest on the East Coast).  Out of fears of potential sabotage, the bridge-tunnel design was conceived, as it allowed the low profile engineers were after, and by tunneling underwater (as opposed to rising above it), it allowed large ships to safely navigate into the Bay, Hampton Roads, and the Elizabeth and James Rivers (for the trip to Richmond).  With this idea in mind, the CBBT opened in 1964, with not 1, but 2 tunnel portions: The Thimble Shoal Channel closer to Virginia Beach and the Chesapeake Channel, closer to the Eastern Shore.  The Thimble Shoal Channel allows access to vessels bound for the Southern Virginia ports, while the Chesapeake Channel allows vessels bound for the Upper Chesapeake Ports (Baltimore, Washington, and even Philadelphia by way of the C&D Canal) to pass.  Pictures don't do this trip justice, so we turn once again to our old friend Freewayjim.  Take a look. 

Allegheny Mountain Tunnel: I-70 and I-76 (Pennsylvania Turnpike) through Allegheny Mountain, Somerset and New Baltimore, PA
Length: 1.1 miles (elevation 2,314 feet)
Toll: Part of closed-system toll road

For tunnel enthusiasts, the Pennsylvania Turnpike is a must drive, the so-called "tunnel highway."  At one time there were as many as 7 tunnels through the Ridge and Valley Appalachians and Allegheny Plateau.  I decided to go with the Allegheny Tunnel for a couple reasons.  First, it's the only turnpike tunnel I've actually been through (while on my way to the Pro Football Hall of Fame in 2008), and it holds distinctions as the longest and highest tunnel in the system.  However, all of the (remaining) tunnels can be given a similar analysis.  When the turnpike first opened in the 1940s (predating the Interstate System), the dualized turnpike had to reduce to 2 lanes as they entered the tunnels, as many of them were converted railroad tunnels.  However, even in rural Western PA, traffic counts started to rise and the tunnels became major choke points.  Therefore, in an effort to improve traffic flow, three tunnels were shut down (Rays Hill, Laurel Hill, and Sideling Hill), and the remaining tunnels (Allegheny, Tuscarora, Kittatiny, and Blue Mountains) twinned.  The really neat (and somewhat weird) thing, is that the old tunnels are still in existence as part of the Abandoned Pennsylvania Turnpike.  The abandoned turnpike was used for testing road technology we all know today (such as rumble strips).  Conservation efforts are underway to convert the abandoned turnpike into a hiking and biking pathway system.  However, years of neglect and vegetative overgrowh have probably made the tunnels structurally insufficient, so nobody dare venture into them.  Anyway, the road to the Allegheny Tunnel is long and windy, literally.  It is part of the longest exit-less stretch on the turnpike (33 miles between Somerset and Bedford), and the climb up Allegheny mountain is something like 5 miles at 6% grade.  It's a killer on your transmission, so take it easy.  The good news for all you geology nerds is that when you do make it, you have reached the top of the Allegheny Plateau, and are crossing the Eastern Continental Divide.  On the Western edge you have entered the Monongahela/Ohio/Mississippi River watershed.  On the Eastern side, you're in the Chesapeake Bay Watershed.  Pretty cool, huh? 

Eisenhower Memorial Tunnel: I-70 Rocky Mountains just north of Loveland Pass, CO
Length: 1.7 miles (average elevation 11, 112 feet)
Toll: None

The highest point along the Interstate Highway System, the Eisenhower Tunnel is just one piece in one of the most challenging engineering undertakings in the history of road construction: Interstate 70 through Rocky Mountain Colorado.  This was not nearly as challenging as Glenwood Canyon (where major steps were taken to preserve the ecology of the area as well), but still not easy.  This allowed ski-crazy residents of Denver to travel to their favorite slopes using Interstate highways instead of the winding and dangerous Route 6 over Loveland Pass.  Another interesting fact about the Eisenhower Tunnel is that its elevation is so high, you get changes from Spring to Winter in no time.  You can see the changes in this series of photographs from aaroads of I-70 eastbound in Summit County.  There are also simiilar perspectives from I-70 westbound in Clear Creek County.  As you make the ascent toward the tunnel, the snowcover on the side of the road increases drastically.  Way cool.

OK...I hope that takes care of your desires for tunnels.  Keep a look out for more road trip and science/engineering features on Caputo's Corner.