What is the function of the crane trolley on a mobile crane?

• A. It rotates the crane base
• B. The trolley moves the hook along the boom for lateral positioning; enables precise load placement but requires careful control to avoid collisions and overloading
• C. It raises the boom
• D. It powers the crane's stabilizers

Answer: (B)

The main idea is how the hoist gets positioned along the boom to place the load precisely. The crane trolley is the carriage that travels along the length of the boom and carries the hoist and hook. By moving on the boom, it provides horizontal or lateral positioning of the load, so you can set the load down exactly where it’s needed without moving the entire crane or rotating the base. This precise placement is why the trolley is essential. It must be operated smoothly and within the crane’s rated capacity at the chosen boom position to avoid overloading or striking nearby objects. The trolley’s job is not to rotate the crane base (that is done by slewing), not to raise the boom, and not to power the stabilizers.