I started my career with the Chicago electric utility in 1961 and in 1964, it started construction on a new large two 500 MW unit coal generating station on the NW side of the Des Plaines river in Rockdale IL. On the SE side of the river was an older coal plant that received its coal by barge. That station was sandwiched between the ATSF RR & the GM&O’s Coal City track. They built a rotary dumper and a three track yard on the bluff next to the GM&O where they could park three 40 car sections of a 120 car unit train.
They bought 260 100+ ton coal gondolas and the GM&O bought about 8 new EMD SD40 units. This made two unit trains which made overnight trips between the Joliet and a mine SE of St. Louis meeting somewhere South of Springfield. We had a small EMD Switcher that had a flat car that had a radio control hut on it that would pull the three sections through the dumper and return them back to their siding. Around 4 PM, GM&O would return with their EMDs and take the train south. It was my understanding that this was, if not the first unit train, it was almost the first.
The coal dumper operator after the switcher was connected to its cut of cars would run through the dumper, all the operator had to do was push a botton to dump the car and return it upright, push button #2 and the switcher would advance one car length. Like your shampoo bottle, says, “REPEAT”. Oh by the way ,dumper was built extra strong to a