Sparks on isolated rail section for animation

A spark will always occur whenever a circuit is made. In your case, perhaps the rails are dirty. You can reduce the sparking by using a relay to activate the gateman.

You can try a tiny bit of conductive oil on the rail. It helps and even sometimes eliminates spark altogether. 

I checked the cars as the track was not dirty.  I cannot believe how dirty the trucks are on some of these cars.  They really made the paper towel black.

All better now, thanks for the advise.

Bill

A good reason to use a relay. Let the relay contacts do the heavy load switching. Load across the wheels is 1 watt or less compared to what an accessory draws.

Described here

http://www.jcstudiosinc.com/BlogShowThread?id=410&categoryId=

If there is still sparking insert a 33 ohm half watt resistor in series with the capacitor.

Dale H