Abstract: At approximately 8:00 a.m. on March 11, 1999, Employee #1 and his assistant attempted to install furnished bogies onto a track carriage. These bogies were taken off from the existed high-rise access equipment at the building. The high-rise access equipment was installed on the wall near the helicopter-landing pad located at the roof of the building. At the time of the accident, Employee #1's assistant was holding the bogie. He was situated on the top of the roof next to the track. Employee #1 climbed the ladder to the working position, and turned his body 180-degree to face to the other side. It was in this position, Employee #1 could summon more strength to work under the track and installed the bogie onto the carrier. The assistant then handed him the bogie. This bogie was too heavy for Employee #1 to hold. This resulted in the ladder moving and slipping. Employee #1 fell, and threw the bogie away to his right-hand side. The bogie hit the wall, bounced and hit his head. After the accident occurred, Employee #1 suffered a head laceration and compressed lumber. Employee #1 remained in the hospital for 10 days for medical treatment.