The four examples built in 1925 from the class 1570 were considered relatively successful from a design point of view, but the power was not sufficient for the assigned applications. In order to increase power, it was decided to replace the four individual traction motors with four double motors, thus creating the power 1670. The additional weight in the electrical system was compensated for by the mechanical equipment being designed to achieve the maximum possible lightweight construction. A series of 29 locomotives was ordered, which were initially manufactured by Krauss in Linz. When Krauss closed the factory in Linz after 24 units, the rest were built in Floridsdorf. The locomotives were stationed in Innsbruck and used from there along the valleys.
Due to the exaggerated lightweight construction, damage frequently occurred, which led to the shutdown of all locomotives. Now all the necessary points on the design have been reinforced, which increased the weight by around ten tonnes and reduced failures. In 1932, five more locomotives were ordered, which were built more sturdily from the factory and were designated as class 1670.1. In the period that followed, there was still damage to the drives, which mainly occurred when the locomotives were being towed. However, it was possible to rework the drives in such a way that the second man to monitor the lubrication could be omitted and less damage occurred in the future. The two series became E 221 and E 222 during the German occupation and they got their old numbers back in 1953. They were used until 1983 and today two examples of the 1670 and one example of the 1670.1 have been preserved. These are the locomotives numbered 09, 25 and 140 and all of them are still running.
