Complex sentence: The contractors who were tasked with the construction of the line to Pietermaritzburg acquired two 2-6-0 tank locomotives early in 1877 for use during construction and named them "Durban" and "Pietermaritzburg".
Split into simpler sentences: The contractors who were tasked with the construction of the line to Pietermaritzburg, acquired two tank locomotives early in 1877, for use during construction. They named them "Durban" and "Pietermaritzburg".