 Each usually saw its general secretary elected to one of the three seats, although the abolition of one seat in 1969 left a battle between ASLEF and the TSSA for the second seat.By far the largest union in Group 3 was the Transport and General Workers' Union (TGWU), although representatives of the National Union of Seamen and a couple of minor unions often secured one seat.The Amalgamated Society of Boilermakers dominated Group 4, with various smaller unions gradually merging into it or the general unions.