"49'ers" are the lowest ranking triad members. A "426" is the top fighter (assuming the number in your question, and not the "428" in your thread title, is the correct one).
Here's some more info on triad "numbers," taken from the footnotes in this article (always wondered if bookmarking stuff like this would ever come in handy
):
http://www.primetimecrime.com/Articles/ ... ge%202.htm
"5. All triad societies display some degree of hierarchy, and a typical triad has members organized by rank. Each rank carries a title and a numerical value, based on triad ritual. The leader of a triad is known as the "Dragon Head' or the Mountain Lord, and carries the rank "489." Other "office bearer" positions include the deputy head of a branch also known as Assistant Mountain Lord, who carries the rank "438". This rank goes as well to the Vanguard and Incense Master, both of whom officiate at ceremonies. The White Paper Fan, who holds the rank "415", is the advisor on administration, finance and organization of the branch. The Red Pole, who holds the rank "426", is the head fighter and battle strategist. The Straw Sandal, holding the rank "432", is responsible for organizing battle and meeting with other societies. He also delivers demand notes when necessary, for ransom or protection money. All other triad members are know as ordinary members or soldiers, and hold the rank of "49"