Smart soft open point to synergically improve the energy efficiencies of the interconnected electrical railways with the low voltage grids

•A novel smart soft open point (sSOP) is proposed to interconnect between railway network with distribution grid.•The sSOP provides additional flexibility and controllability for both networks.•An integrated simulation platform of rail and grid has been developed to evaluate the proposed sSOP.•The aggregated braking efficiency of the railway network is improved.•The local consumption of the RES in the LV grid is increased.•The energy consumption from the LV grid supplying point is reduced.