Because of the current state of global resource shortages and environmental degradation, energy-saving and environmentally friendly national policies and low-carbon concepts have attracted both individual and societal attention, especially for rail transit. The rapid development of high-speed railways and urban rail transit in China has presented increasing transport energy demands and environmental pressures. This paper conducts an energy consumption comparative analysis of high-speed trains with different marshaled forms, including 3, 5, 8, 10, 12, 16, 17 and 18 cars, using the delayed detached eddy simulation method. A wind tunnel test with a 3.6% difference is applied to verify the obtained numerical results. A multiple-criteria evaluation methodology is presented to select the optimal alternatives for the marshaled forms of high-speed trains, which considers economic, social and environmental factors. The 1318-km (820-mile) Beijing-Shanghai line and a 350-kph high-speed train are employed in this research. The results can effectively guide the engineering design of high-speed trains and provide an evaluation tool in the decision-making process for designers.