Originally Posted by Baronvonellis
Why was the Kennedy only capped in that one spot? Just for a parking lot and storage. It seems like a waste.
In addition to the big railyard above, the fact that Halsted also crossed on an angle created some unique structural needs - the supports for the Halsted overpass fell directly on top of the Kennedy beneath.
The least expensive way to layer everything together was simply to dig a trench for the Kennedy and then cap it with big plate girders deep enough to support several freight trains and another overpass on top. Also, the C&NW (which owned the railyard) was an extraordinarily powerful corporation in 1960s Chicago, so they had to be accommodated at great cost. Even Marshall Field, when he built the Merchandise Mart, had to accommodate another C&NW railyard beneath the building.
It certainly wasn't a quality-of-life issue that made them build a cap... this area was highly industrial and nobody lived nearby to care about greenspace or pollution. Remember, they didn't even cap the IC through Grant Park until the 2000s when Millennium Park was built.