The set consists of 2 solenoid activated gates, each with 2 red warning lights which go on when the gates descend. Dimensions for each base 96 x 37 mm / 3-3/4" x 1-1/2". The following are required for the railroad crossing gates: for manual operation: 1 manual signal controller 8946. for automatic operation by a passing train: 1 each 8945 universal relay and 2 circuit tracks (8529, 8539 or 8589 according to the layout) per track.