Optimization Model for Operation of Battery Multiple Units on Partly Electrified Railway Lines

This paper aims to demonstrate the applicability and flexibility of a direct method optimization model for battery electric railway operation on partly electrified lines. The proposed algorithm allows the simultaneous optimization of both the speed profile and the power control, including battery recharging with the condition of charge-sustaining operation. It is shown that the optimization model is capable of reducing the overall energy demand at the overhead line in comparison to a non-optimized operation strategy. Simulations were conducted for four different electrification scenarios, yielding major improvements in all cases not only for the energy demand at overhead line, but also concerning battery lifetime when compared to the non-optimized strategy. In addition, the analysis of battery stress reveals noticeable differences in estimated battery lifetime between the different scenarios laying the groundwork for future economical evaluations of battery electric railway operation and electrification patterns.