Representational Pic

Indian Derby hopeful Castlebridge who, according to bloodline experts, is not exactly bred to stay the Derby trip of a mile-and-a-half, will undergo his first test of stamina at the Mahalaxmi racetrack today evening when he will run in the ten-furlong Ramniwas Ramnarain Ruia Gold Cup (Gr 2), the feature event of Sunday's eight-race card.