A modular high voltage supply system has a mobile adapter transformer with a high-voltage output side and a low-voltage input side, electrical connecting input-terminals being foreseen at the mobile adapter transformer outer surface, a mobile container with a low voltage supply system, mounted stationarily therein, having a high current busbar and at least one electrical frequency converter connected thereto, electrical connecting output-terminals for the high current busbar being foreseen at an accessible the mobile container edge; and a modular interim busbar system, for temporary electrical connection of input- and output-terminals, having at least one interim busbar with at least one elongated busbar basic module mounted on a frame structure and respective resilient electrical connections on both busbar basic module ends forming an electrical connection to the input- and/or output-terminals and arranged such that a transmission of vibrations from the mobile adapter transformer to the mobile container is suppressed.