Abstract: On October 31, 2012, Employee # 1 was working as a SFMTA Wire Rope Maintenance Mechanic or Splicer at the Cable Car Maintenance Barn. Splicers adjust the stretched and /or damaged steel cables by moving the Tension Carriages and/or cut and splice a new piece of cable. More than half of the 20-foot diameter of the Tension Carriages are above the ground but approximately 8-ft of them are below grade and inside concrete channels 9 to 9.5-ft deep and 3-ft wide. The channels are covered by planks approximately 11-ins. wide and 5-ft long. Cable Cutting and Splicing is performed between 1 a.m. and 5 a.m., when the cable car operation is shut down under Lock-out and Tag-out. At approximately 1 a.m., Employee #1 and a coworker were assigned to cut the cable of the California Line. Since the Carriage was already pushed all the way to the back of the Barn, it had to be pulled forward. After removing an old portion of the cable and replacing it with a new and shorter one, the Carriage was located approximately 25- ft from the back wall, and except for five planks that the two Splicers were standing on. The rest of the planks had not been replaced. The triple sheave block & tackle was attached to the strong back with a clevis pin. The pin had to be removed and a new sling had to be added since the Carriage had been moved forward to a new position. At approximately 2 a.m. as Employee #1 removed the Clevis pin. The employee used a hook that was attached to the B&T's Shackle to pull it to the side but the assembly surged and Employee #1 lost his footing and fell into the concrete channel. Paramedics were called, and the employee was transported to an area hospital, where he was treated for broken ribs, a collapsed lung, and lacerated kidney. Employee #1 was hospitalized for two days.