I'm proud to say that we're working on some ambitious transit projects in America right now; the new Hudson River ARC tunnel is an obvious example. But last week I had the opportunity to tour the construction site of what will become, when completed, the world's deepest immersed transit tube: the Marmaray Tunnel in Turkey.
This is one of those engineering marvels that kids--and adults--around the globe will be reading about someday and saying, "Wow! How did they ever do that?"
The world transportation community is already watching and hoping to learn from Turkey's experience.
The Marmaray tunnel will not only connect the beautiful city of Istanbul more efficiently with its eastern suburbs; because Turkey has one foot in Europe and one foot in Asia, it will also be the world's first intercontinental submerged public transit route.
“Yes, you will be able to go from Europe to Asia without getting off the train,” said Serap Timur, of Turkey’s General Directorate of Railways, Harbours and Airports Construction (DLH).
The underground segment of this 47.5 mile project will be about 8.5 miles. The crossing beneath the Bosphorus Strait will measure .87 miles and consist of two tubes with 11 sections of immersed tunnel. At its deepest, the tunnel will be submerged to a depth of 197 feet.
Visiting the site was exhilarating. To see how the tunnel segments are floated into position then submerged into a waiting trench then connected--it's really something.
But not only is this exciting from an engineering perspective; it also promises tremendous benefits to the Turkish people.
First, because of the existing process--arriving at a transit terminus, waiting for a ferry, crossing the Bosphorus, and picking up a train on the opposite side--the Maramaray Tunnel will trim 80 minutes from the Gebze-to-Halkali transit line. That's nearly an hour and a half saved each way!
Second, the revitalized transit system will be able to accommodate 75,000 passengers every hour. That's a huge increase--750%--over the current capacity of 10,000 per hour.
And, since many commuters currently depend on the two existing roadway bridges, this project promises to reduce congestion on those routes and cut greenhouse gas emissions dramatically.
Plus, in addition to the three new underground stations, the Turkish Rail System (TCDD) is refurbishing 37 stations along the length of the Gebze-Haliki line. TCDD is also bringing in entirely new electrical and mechanical systems and upgrading track. We're talking about a completely rejuvenated transit line.
Further, the tracks are designed to accommodate freight and passenger rail as well as transit. So, in between transit rush hours, goods will have a much more efficient route between the two continents. This means it will soon be possible to travel by train all the way from London through Marmaray and into China.
I don't think you have to be a transit fanatic to get excited about the scope of this project. But this is only one feature in Turkey's game-changing approach to transportation. Later, I'll blog about their new high-speed rail line and other ambitious projects. So please tune in to see what lessons American transportation planners can learn from this extraordinary effort.