The BNSF ex-Frisco St. Louis-Memphis line is about 1/2 a mile from my house, and I see trains on this line quite often as I drive on Interstate 55 south of St. Louis.
UP is a bit farther away, but I sometimes sit and watch a few UP trains go by as they pass through Valley Park, MO.
Once in a while I see a NS train crossing the Missouri River bridge near St. Charles, MO. I really miss the Santa Fe railroad--if I modeled modern stuff I would definitely be a pre merger ATSF modeler.
Jeff C