Gilbert produced the American Flyer Accessory 762 2 in 1 Whistle and cataloged it in the 1949 and 1950 catalogs. The whistle was unique as it featured two separate whistles with two buttons.
The 568 whistle was produced in 1956 and had a green plastic base. The whistle was different from earlier years as Gilbert continued to move towards plastic materials.
The 577 whistle was produced in 1947 through 1950 and had a green metal base. The whistle was different from later years as Gilbert began to move towards plastic materials.