Paragraph 6 I1

be accompanied by four red lamps which, in operation, show an intermittent red light at a rate of flashing of not less than 60 nor more than 90 flashes per minute and in such a manner that the lights of one vertical pair are always shown when the lights of the other vertical pair are not shown; and

have the red cross shown in the diagram at item 14 or 15 of the sign table in Part 2, or the white symbol shown in the diagram at item 16 of that table, illuminated by a steady light when the red lights are flashing.