Highball Signal is a historic railroad signal located at Delmar, Sussex County, Delaware. It is a white sphere mounted on a pole and located next to the railroad tracks to signal permission for a train to proceed at full speed, if the ball was at the top of the pole. The term "highball" came to be synonymous with a clear right-of-way and for trains to proceed at full speed. It was originally in service at New Castle, Delaware, and then at Hurlock, Maryland.