Omar Barragan, Host: It's one of the most unique pieces of architecture along the CTA system
and it is a signature structure on the Illinois Institute of Technology campus
"It" is the Exelon Tube which encases a section of Green Line track
above the McCormick Tribune Campus Center.
The Exelon Tube - a striking testament to human ingenuity,
The 530-foot-long steel and concrete structure is 
the focal point of the Illinois Institute of Technology at 32nd and State. 
It incorporates the 'L' tracks into the design and caps the 
110,000 square foot McCormick Tribune Campus Center - opened in 2003.
>>"From the moment the design was revealed
people here on campus were just very intrigued
to see it built -- particularly the tube."
>>Rem Koolhaas of the Netherlands submitted the winning design in 1997 
when IIT decided to build a new campus center. 
>> "We had envisioned a building that would have to sit
on one or the other side of the CTA tracks 
and Koolhaas came up with the idea 
that the building would kind of slide underneath the tracks."
>> The Tube's function was to muffle the sound of the Green Line trains
as they pass over the building on approach to and departure from 
the 35th-Bronzeville-IIT station.
>> "I know when the design first came in, we in the CTA engineering department 
were very impressed with it. Not only the campus center,
but the enclosure, the tube, that would go around our elevated tracks."
>> But there were some concerns. 
The original design called for a totally enclosed structure.
>> "We wanted to see that open, the top of the roof open, to allow daylight to enter
to allow free ventilation, also to relieve air pressure 
as the train enters and leaves the tunnel."
>> CTA also needed a guarantee the project could be done without disrupting service.
>> "They were very cautious about how they were
going to factor this
against the stringent expectation for service that the city has for them."
>> "We were able to provide a window for them to work at night 
when the Green Line trains weren't running."
>> "So we were building from midnight to 
5 a.m. for two years 
and then and only then could we build the building that
slides underneath the train tracks."
>> The end result is a city block-long tube 
with regularly spaced steel arches on top and a reinforced concrete bottom.
The trains are little more than background noise inside the center
where students study...
socialize...
...and even operate a radio station.  
>> "Sound can only travel in one direction.  
So if it's traveling up to the top of the tube, 
it's going to go up to the heavens."
a series of support columns holds the structure in place.
>> "The black painted steel columns hold up the roof of the building.
The exposed concrete grade square columns hold up the train tracks, 
and then there are these diagonal pylons
which are painted black and they're massive
and that's what's holding up the Tube."
>> The tube itself is a must-see for architectural buffs from around the world.
>> "I think it's become a definer for Chicago.
Certainly in architecture circles people are highly interested 
in what you put here on campus.   
We get busloads of people coming to look at the tube."
"I don't know if it's been in a movie yet, 
but I bet it will be."

>> You can see the Tube for yourself.
The campus center is open to the public until 7 p.m. daily. 
Contact IIT for information on guided and audio tours.
