between Pretoria and Johannesburg with effect from 16 January 1984. Five locomotives were delivered by UCW in 1983, numbered in the range from to 12-005. Like the Class 6E1, Series 6 to 10, the Class 12E units were equipped with AEI-283AY traction motors. UCW did not allocate builder's numbers to the locomotives it built for the SAR, but used the SAR unit numbers for their record keeping. Characteristics Based on the dual cab Class 6E1 locomotive, the Class 12E was a single-cab locomotive with a conductor's cabin at the rear end. They were used with specially designed suburban passenger coaches which rode on air-sprung disk-braked high speed Scheffel bogies. The MetroBlitz operated with two locomotives per train, one unit at each end, which made dual cabs unnecessary. Like the Class 6E1, the Class 12E was built with sophisticated traction linkages on their bogies. Together with the locomotive's electronic wheel-slip detection system these traction struts, mounted between the linkages on the bogies and the locomotive body and colloquially referred to as grasshopper legs, ensured the maximum transfer of power to the rails without causing wheel-slip by reducing the adhesion of the leading bogie and increasing that of the trailing bogie by as much as 15% upon starting. This feature was controlled by electronic wheel-slip detection devices and an electric weight transfer relay which reduced the anchor current to the leading bogie by as much as 50A in notches 2 to 16. The Class 12E had the same power output as a Class 6E1, but with a higher gear ratio of 23:66 compared to the 18:67 of the Class 6E1. This enabled it to run at a safe maximum speed of . Since it was designed for suburban service, sanding gear was deemed unnecessary and was not installed on the Class 12E, as evident from the absence of the sandbox lids seen along the bottom body sides of most Class 6E1 locomotives. This turned out to be a disadvantage when they were eventually allocated to mainline service to haul the Blue Train. Demise Poor cost recovery and disruption to other slower train services are cited as the reasons for the demise of the MetroBlitz. After the MetroBlitz service came to an end in 1985, the five Class 12E locomotives were repainted blue with yellow whiskers and replaced Class 6E1 numbers E1341 to E1345 as Blue Train locomotives between Pretoria and Kimberley. Probably