Abstract: At 8:30 a.m. on October 15, 2018, and employee was being trained in the process and procedure of loading and unloading rail cars. The yard supervisor was showing the employee and a coworker how to release the straps holding the material on the rail car. As the employee was working from the rail cars catwalk that measured 73 feet long by 40 inches wide to release the straps, the coworker was located on the ground to roll up the straps as they were released. After the supervisor instructed the employee how to release the straps, he descended the ladder/steps from the top of the rail car. While exiting the catwalk, the supervisor turned to look at the employee and witnessed him step onto a plastic sheeting that covered the material on the rail car and fall approximately 12 feet to the bottom platform of the rail car. The employee sustained a broken right wrist, broken ribs, and a punctured lung, which he was hospitalized and received treatment.