The question What is a "rail system"? What about rods? was closed as a duplicate of What is a focusing rail?. Since the former is about rail systems used to mount additional equipment (e.g. pull focus system, matte box, monitor, etc.) used in video shooting and the latter is about focusing rails used in macrophotography, the former is definitely not a duplicate of the latter and should not have been closed as such. Please join me in voting to reopen.