Optimization of Train Speed Curve for Energy Saving Using Efficient and Accurate Electric Traction Models on the Mass Rapid Transit System

Rail transport systems play a crucial role in public transport systems in that they are highly effective in mitigating traffic jams, maximizing transportation capacity, minimizing air pollution, and reducing energy consumption. This paper optimized the operation of a single rapid transit train between stations for energy conservation. Past studies investigating energy conservation in train operation only considered the consumption of mechanical energy or assumed a constant efficiency value for the direct conversion of mechanical energy to electrical energy consumption. However, a train using minimal mechanical energy does not necessarily imply that its input electrical energy is minimal. Therefore, only through direct minimization of electrical energy consumption the goal of energy conservation in train operation can be achieved. Simulation results from the conventional mechanical model, the exact model, and the proposed model indicated that the conventional mechanical model could not reflect the actual electrical energy consumption and consequently could not yield the optimal train-speed curve. Simulation results from the exact and the proposed models revealed small differences between their energy consumption calculation results. The model this paper proposed greatly reduced the simulation time. Moreover, when the coasting mode was added to the proposed model, the operational energy consumption was reduced by approximately 58%.