Headcode 33, Robert Waterman says "I cannot find headcode 33 although I believe it was used from about 1963 to 1977 for London Bridge - East Grinstead (headcode 77 used thereafter). Similarly headcode 22 was used for Victoria - East Grinstead for the same period (thereafter headcode 66). The changes came about, if I recall correctly, as a result of the mass SR Central Division headcode changes of 1977. "