Joe,
 The buzzing sound as trains cross the switch is caused when the train wheels bridge the insulated switch rail and energize the switch coil. This is the anti-derail feature of these switches and is normal. If the caboose light goes off when its roller is on the fat center rail, or the other middle rails, there may be a bad connection internally. You need to determine exactly where you lose power, on the straight portion or curved portion, or both. On the straight portion, you may lose power either on the fat center rail, or the other normal center rail. A quick fix would be to add 3 lockons; one on each track connected to the switch.

Larry