Complex sentence: The bulk of the Class GF fleet worked in Natal, some stationed at Empangeni to work the sugar cane traffic from Mtubatuba, while most were based at Mason's Mill to work the various branches which radiated from Pietermaritzburg.
Split into simpler sentences: The bulk of the Class GF fleet worked in Natal. Some were stationed at Empangeni to work the sugar cane traffic from Mtubatuba, while most were based at Mason's Mill to work the various branches which radiated from Pietermaritzburg.