The relatively poor power quality

low capacity utilization and high electricity costs in the existing railway traction power supply systems (TPSSs) become the pain points for the railway and power system sectors. To tackle this issue

this paper proposes a railway virtual power plant (VPP) concept based on the flexible interconnection technology for different phases in a TPSS

which achieves economic benefits improvement on the premise of meeting the technical indicators for grid-connection. Besides

a carbon emission reduction regulation strategy is put forward and a capacity design model is constructed. Firstly

the primary architecture for the railway VPP is established. For the trading requirements of the carbon market

the railway VPP carbon emission reduction regulation strategy is proposed. Moreover

the railway VPP capacity design approach considering the optimal economic benefits is put forward. Finally

based on the field data and the typical operating conditions

simulation verifications are performed. The results show that

the daily power consumption of the electrified railway in the 3-phase power system is reduced by 10.72%

the regenerative braking recovery rate is 85.2%

the average power factor increases from 0.60 to 0.93

and the electricity bills are decreased by 54.54% during the project period

which verifies the important theoretical and engineering values of the proposed railway VPP.