On the evening of Sept. 24, 1976, as RF&P manifest No. 110 worked its way north, a wheel began of disintegrate on a SCL boxcar. It began around Dahlgren Junction (MP 61.1) and by the time the car had gotten to Brooke Siding (MP 68.5) the wheel was gone and the truck was riding on the ties. When the car got to the switch, it took it out and a derailment followed. The following day, both the Acca (on left) and Potomac Yard (on right) derricks were working to clear the tracks. The Potomac Yard derrick was smaller and had a shorter boom, with the end painted yellow, for working under and around catenary.