This document is applicable to the new construction of fixed electrical and mechanical systems of urban rail DC lines. This also includes non-conventionally operated track-guided urban railways that fulfil the same functions, e. g. suspension railway systems, passenger transport systems. This document is not applicable to fixed electrotechnical installations of railways of all track gauges, track-guided buses, trolleybuses, light rails, mine railways, park railways, mountain railways and cableways as well as amusement rides and railways used exclusively for historical or tourist purposes. NOTE Urban railways operated as tram-trains are within the scope of this document up to the defined local boundary, outside of which the regulations for railways apply. This document defines specific technical characteristics, the principles for design, construction/manufacture, operation and maintenance as well as general requirements for the new construction of the following fixed electrical and mechanical installations: - traction current supply systems; - overhead contact line systems; - energy supply systems; - lighting systems; - mechanical equipment. If this document specifies requirements for the construction of fixed electrical and mechanical systems that differ from the previous national regulations, existing fixed electrical and mechanical systems or those under construction do not need to be adapted to the requirements of this document, provided that there are no safety-related issues that prevent commissioning or continued operation. This document does not specify any requirements for signalling, train protection and communication systems.