Abstract: One variation for a system for tracking lifting events at a construction site includes: a chassis configured to couple to a crane block of a crane at a construction site. The system further includes a first idler assembly including a first cable idler, a first idler arm, and a first position sensor coupled to the first idler arm. The first idler arm supports the first cable idler on a first side of the chassis and biases the first cable idler inwardly toward a first cable loop coupled to the crane block. Additionally, the system includes a controller configured to, during a lift event: read a first position value from the first position sensor; predict a weight of the load carried by the crane block based on the first position value; and generate a lift event record containing the weight of the load carried by the crane block.