My father, Dr. R. D. Leonard, snapped this transparency of The Limited departing Bloomington for Springfield and St. Louis in July 1962. EMD F3A unit 103-A leads a "B" and another "A" unit. According to the late William K. Dunbar, the signal in the background was a "repeater signal" to provide a block indication for the southbound crew. All trains had to stop at "BN Target," which protected the crossing at the depot with the Nickel Plate and the Peoria & Eastern, and crews were changed at Bloomington. Since the train had stopped within the block, the new crew needed a block indication upon departing; they were not to rely on verbal information from a crew arriving from the south, because conditions in the block could change in the interim.
Mr. Dunbar further noted that the weedgrown siding in the foreground was a holdover from the days when steam locomotives were changed at Bloomington. The new engine waited there until the arriving southbound train's engine uncoupled and pulled past the switch. It then backed toward the depot to couple to the train, while the arriving locomotive backed through a crossover (note the switch stand ahead of the locomotive pilot) and proceeded to the roundhouse via the northbound track.