The development of a partially remote controlled and automated long distance flushing system used during maintenance is part of the maintenance strategy of the Austrian Federal Railways (ÖBB Infrastruktur AG). The so called MDR (modular drainage flushing system railway) will come into use in the three new railway tunnels Granitztal Tunnel, Koralm Tunnel and Semmering Base Tunnel along the Southern Railway Line. The flushing system consists of the major components MDR flushing box, MDR transport module and various permanently installed components such as flushing shaft, water supply, electricity and data connection. During drainage flushing the MDR is positioned on top of the central flushing shaft in the respective crossway area and connected to the required infrastructure. With the proposed hose length of 600 m, the remote‐controlled flushing system flushes all drainages along a length of 500 m in both tunnel tubes as well as the crossways. Once the flushing process and quality check via camera inspection have been completed, the MDR flushing box is moved to the next site at the next crossway during a break in operations. During the flushing process itself, railway traffic does not have to be interrupted. Track closure is only necessary when the MDR is being relocated. In order to increase the MDR flushing box's flexibility the system should also be usable on the tracks themselves.