sentences:  During construction, groundwork and electrical equipment was contracted to developers, while the trackage was done by the planning office.The original plans called for the use of 600 to 650 volt (V) direct current (DC) fed via a pantograph, to allow comparability with the light rail.This was later changed to 750 V DC via a third rail, allowing reduced maintenance costs and a larger contract surface, permitted a larger electric current and more power to the trains.