30/40T Trolley Replacements

Advanced Crane Technologies supplied and installed one 40-ton and one 30-ton overhead electric traveling trolley at the Naval Air Warfare Center Aircraft Division. These new trolleys were custom-designed to replace aging systems inside anechoic chambers used to suspend extremely high-value loads—some exceeding $100 million—for extended periods. Because personnel often work near or briefly beneath these loads, the trolleys were engineered to meet the Navy Crane Center’s most stringent safety and reliability requirements.

The replacement trolleys feature comprehensive single failure proof mechanisms, including a dual load path reeving system, a 6:1 safety factor hook, disc brakes acting directly on the rope drum, a broken shaft detection system, unbalanced load detection at the equalizer bar, and a drum pawl engagement system. The complex removal and installation process—executed in a confined and sensitive environment—underscored ACT’s specialized capabilities in high-security, high-precision crane applications.

Overcoming Removal & Installation Challenges

The project demanded far more than standard equipment replacement. The original trolleys had been installed during facility construction, with no practical provisions for future removal or replacement, a common limitation in specialized, top-secret test facilities. ACT’s team had to design and execute a plan that would navigate these constraints while ensuring structural integrity and security compliance.

For the 30-ton trolley, a removable roof hatch was engineered, cut, and reinforced into the building structure. This provided the only feasible path to extract the old unit and lower in the new assembly. Strategic planning, placement, and coordination ensured the operation went flawlessly. Roof access panels were installed, sealed, and restored without incident.

The 40-ton trolley required even greater ingenuity. Engineers assessed the roof truss structure to determine safe load paths and installed temporary rigging components capable of bearing the trolley’s weight. Using hand chain come-a-longs, the team developed a transfer system that allowed the trolley to be picked from an overhead crane at full stick, rotated vertically with only inches of clearance between trolley rails, and then carefully transitioned back into horizontal position for final alignment. This highly choreographed process required detailed engineering of load transfers through the existing building framework and precise rigging control, yet the execution was flawless.