The invention discloses an opening-closing top cover for a railway wagon and the railway wagon. The opening-closing top cover comprises a cylinder, a connecting rod and a movable top cover. With the adoption of the movable top cover, a boxof the railway wagon can economically and efficiently transport some granular cargoes which require moisture preventionor are harmful to the environment. The movable top cover can slide along a wagon roof with a variable arc radius section or a sidewall, so that the clearances of railway locomotives can be fully utilized to increase the capacity of the wagon, and the center of gravity of the wagon can be lowered.