The 606 boasts another number:
38.
That’s how many bridges spanned the 2.7-mile stretch of former rail bed on the Near Northwest Side that is being turned into a walking and biking trail and park system.
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On Saturday, you can learn about them, do your own model bridge-building and get a look at the under-construction Milwaukee Avenue bridge with the city’s chief bridge engineer.
The latest installment in The 606 Trail Mix series is a free, family-friendly drop-in event that celebrates the bridges that made the rail bed possible.
“It’s our history,” said Luis Benitez, the chief bridge engineer. “They’re beautiful architecture, beautiful old structures, and we’re trying to reuse this infrastructure and incorporate it into … this beautiful 2.7 miles.”
The bridges were constructed to elevate the system’s train crossings, which were originally at grade level, said Jean Linsner, Exelon Fellow for Education at The Trust for Public Land, The 606 Trail’s lead private partner.
Grade-level crossings are dangerous. More than one person a day was being killed at grade-level crossings in Chicago, Linsner said. So in 1893, railroads were mandated by law to start elevating their train crossings in the city.
The Bloomingdale Line was one of the last to be elevated. As a result, by the time the work was done in 1915, the railroad was able to rely on construction advances — and do the work while the train line was still operating.
The 606 thus sits on top of engineering history.
“They used really advanced practices in the use of concrete,” Linsner said. “One hundred years ago it was quite a model in terms of construction.”
The bridges have been a focus of construction of the 606, which is scheduled to open in June 2015.
The bridge over Ashland Avenue was picked up and moved — on a truck with 88 wheels — to Western Avenue, lowering The 606’s bridge count to 37.
The Milwaukee Avenue bridge is being revamped; the concrete piers that supported it will be removed and replaced with arches that will support the bridge from above.
On Saturday, families will be able to design and build bridges out of recycled material; use toothpicks and marshmallows to figure out how much load their bridges can carry; and make a human suspension bridge that will allow people to feel how the cables in a suspension bridge work.
And Benitez will take groups to the Milwaukee Avenue bridge and discuss steel girders, suspension bridges and, he promises, “everything anyone would want to know about engineering.”
“Bridges: Up, Over, Through and Down” will be at the Bucktown-Wicker Park Library, 1701 N. Milwaukee Ave., from 11 a.m. to 2 p.m. Saturday. More information is at the606.org/events/.