A crossing gate mechanism includes a swingable gate arm, a rotatable gate arm shaft fixed to the gate arm, and an electronic sensor assembly coupled to the gate arm shaft. Rotation of the gate arm shaft corresponds with swinging of the gate arm. The electronic sensor assembly senses an angular position of the gate arm shaft and transmits a position signal corresponding thereto. The electronic sensor assembly includes a driving element that is attached to the gate arm shaft to rotate therewith. the electronic sensor assembly also includes a driven element that is driven by the driving element such that rotation of the gate arm shaft causes the driven element to rotate. The electronic sensor assembly is configured to generate the position signal based on a position of the gate arm shaft.