The Jaguar!, a Zierer jr. steel passes through the loop of the classic flywheel driven Schwarzkopf shuttle loop, Montezooma's Revenge. When Jaguar! first opened only the track was there, but at a later date a cage was added over the Jaguar! track to ensure that the track and riders were protected from debris coming off of the Monte trains as they traverse the loop.
Here is a pic, courtesy of of the RCDB:
http://www.rcdb.com/installationgallery292.htm?Picture=1