Built by Brush Traction between 1957 and 1962, the Class 31 was designed as a replacement for steam traction in various regions. These six axle locomotives had a high tractive effort and could easily handle both freight and passenger services. 263 class 31s were produced and throughout their operational career they had many different sub-classes and operators. By 2017 the class was withdrawn from service and 36 locomotive were preserved.