Welcome to the forum. First, does your train slow down as it approaches the switches? If it does, you have a power drop in the area and you need to add lockons to distribute power evenly. If power distribution is not a problem, take your lighted caboose alone and roll it slowly over the switches. Does it lose power when going through the switches? All train wheels will spark a little as they roll over the switches due to the wheels completing the anti-derail circuit. Make sure the roller pickup is not shorting to the curved swivel rail also. Let us know your results.

Larry