BS 555:1962

Gas filled train lighting lamps; bus interior lamps; navigation lamps; road traffic control (electrical) light signal lamps; double-capped tubular lamps; general service lamps for use on 100, 120, 200 and 220 volts. Mushroom shape lamps are also included. The requirements are based on BS 161 and include dimensions, bulb finish, test voltage, initial readings, lumen maintenance and lamp cap temperatures for each type of lamp.