AUSZUG | eb - Elektrische Bahnen INT 2/2015

85 113 (2015) INT 2 Projects expansions are already in the planning and exe­ cution stages. Phase IV will follow on immediately and is scheduled to run until 2021. Delhi is truly a mega-city with a population of eleven million, whereby this figure does not include the city’s out- lying suburbs. The rail systems are routed separately from the road system and run on viaducts or in tunnels; only the depots are at ground level. The operating speed is 80 km/h. The Airport Express line from New Delhi railway station to the new airport used to run at a higher speed, but since its integration into the DMRC it is now subject to the same conditions as the rest of the network. The articulated metro vehi- cles run in formations of six or eight cars, whereby every second car is powered and equipped with an own pantograph. 2.2 Overhead contact line Many details in the system design and configura- tion of the overhead contact lines in Phases  I and II betrayed French roots. Initial plans for using a DC traction power supply were quickly abandoned in favor of a simple AC 25 kV 50 Hz power supply sys- Figure 1: Indian Railways (IR) network (all figures: Siemens).