Flexible power supply for DUOline rail If the rails cannot be laid directly above the power outlet, there is the flexible power supply from DUOline. It is one of numerous components of the rail system and is used to bridge the power supply by a maximum of 1 metre. This means that a planned power feed can be achieved even if it is not directly above the rail - requires an additional longitudinal connector when used as an end power feed or two longitudinal connectors when used as a central power feed (see accessories)