Vulcan Surf Rail Channels

I hesitate to ask but going to anyway. Does any one know how Vulcan does their channels?  I am very intrigued.  Machine shaped?  Or some advanced template?  I do mine with a rail marking tool and a short piece of PVC pipe with sandpaper wrapped around. They turn out fine but Vulcan is in a whole 'nother league. 

all the best

Dane uses a machine.