Alliance Grain owns the Bloomer Line. It is most busy in the fall and winter when the crops are being harvested. However, it also serves several industries. The Bloomer interchanges with CN and NS at Gibson City, and also serves a couple of industries there. I don’t know how busy the Bloomer is around the 4th of July, but since it is a slower time of year, and a holiday, the Bloomer will probably not run on the 4th. I'm not sure about how often they run during the summer, but some of their industries get quite a few cars. I would assume that they operate during the day, perhaps leaving Gibson City in the morning and returing in the afternoon/evening. I would recommend railfanning around the Gibson City area, since both NS and CNIC traffic will give you something to watch if nothing is moving on the Bloomer. Also, their shops are located in Gibson City so be sure to check that out.
A little more info on the bloomer plus a map and a small amount of locomotive and customer info can be found