Installing a crane and positioning its trolley require careful planning, accurate measurement, and strict adherence to tolerances. Begin by reviewing drawings, foundation bolts, and the crane runway. Verify that columns, runway beams, and rail centers match the approved layout. Clean all connection points and check anchor bolt threads. Use shims and leveling nuts to set base plates before final grouting. Next, install the crane runway rails. Establish a centerline with a laser or theodolite, then align rails by elevation, span, and straightness. Use rail clips, fishplates, and expansion gaps as specified. Check rail gauge at several points to prevent diagonal binding. Tighten bolts in stages and recheck alignment after each pass. Position the bridge or end carriages on the runway. Lift the bridge with certified equipment and lower it slowly onto the rails. Confirm that wheels sit fully on the rail heads and that clearances are equal. Adjust end stops and buffers so the crane cannot overrun. Verify bridge diagonal measurement; unequal diagonals can cause skewing. Trolley positioning is critical. Place the trolley on the bridge rails or track, then align its wheels with bridge centerline. Set trolley so its wheel gauge, clearances, and travel limits meet manufacturer data. If the trolley is top-running, check wheel flange contact; if under-running, check side rollers and guide clearances. Use jacking bolts, shims, or adjustable bearing housings for fine positioning. Recheck torque.