On Sunday, April 14, the CTA ran two historic 4200-series cars between shops. This video (not mine, BTW) covers a portion of the trip, basically clockwise around the Loop (Lake St., Wabash Ave., Van Buren St. and Wells St.), and then north on the Red Line. It gives a good view of the route, some signalling, and the close clearances the el track has with some of the buildings. It was not a "fan trip", and was unannounced, except for within the CTA. The cars are by Cincinnati Car Company, and date to 1922-23.
http://www.youtube.com/watch?v=ennJzHZKkCE