Charlie:
It was called the Division Street Yard by the Milwaukee Road. You can see pictures of it in its last days during the mid 1980s in the Goose Island section of this website, including the graffiti covered freight house.
The yard and related structures were gone by about 1991 as Milwaukee Road corporate successor Chicago Milwaukee Corporation (CMC) began to sell off and develop the land. What remained were a runaround track in dirt-paved Cherry Street to service International Salt and Big Bay Lumber and a pair of team tracks on the east side of the island at Hooker and Division Streets to serve off-line rail customers. The team tracks were in service through at least 1996.
Soo Line took over railroad operations from the Milwaukee Road in 1985 while the real estate holdings and most legal obligations including mitigation of brown fields were absorbed by CMC. CMC was the largest single landowner on Goose Island at the time by virtue of the vacant yard and related property.
CMC successor CMC Heartland Partners, eventually known as just Heartland Partners, finally dissolved in 2006 as the last of its properties were sold off. You can read more about this chain of corporate ownership by reading the online filings at the Securities and Exchange Commission (SEC) website.
For more information please check out the book I authored on The Milwaukee Road in Chicago which came out in late 2007 and is available from the Milwaukee Road Historical Association (MRHA). It includes detailed descriptions of operations at the Division Street Yard as well as across Goose Island with aerial photos and maps.
Tom