Miniature stoplights
8.—(1) The crossing signs shown in diagrams 107 and 108 shall contain red and green lamps which are internally illuminated by a steady light in such a manner that—
(a)when one light is illuminated the other is not illuminated;
(b)the green lamp is and remains illuminated for so long as no railway vehicle is approaching the vicinity of the crossing from either direction; and
(c)the red lamp is and remains illuminated for so long as the green lamp is not illuminated.
(2) The lenses of the lamps shall be—
(a)circular and not less than 60 millimetres in diameter; or
(b)rectangular with each side measuring not less than 60 millimetres; and the distance between the edges of the lenses of the green lamp and the red lamp shall be not less than 40 millimetres.
(3) The information, warnings, requirements and prohibitions conveyed by the lamps described in paragraphs (1) and (2) shall be as follows—
(a)the red lamp when illuminated shall convey the warning that a railway vehicle is approaching the vicinity of the crossing and the prohibition that persons must not proceed across the crossing;
(b)the green lamp when illuminated shall convey the information that no railway vehicle is approaching the vicinity of the crossing and persons may proceed across the crossing;
(c)if neither the red nor green lamp is illuminated persons should either telephone the crossing operator or proceed across the crossing with caution after having ascertained that no railway vehicle approaching the vicinity of the crossing in accordance with the instructions shown on the sign.