通过构造适当的分析模型,并以ND5型和SS7型机车分别牵引不同质量的空、重货车为计算条件,对列车节能运行第三论断进行了分析论证,并揭示出其成立的本质。 By constructing an appropriate analysis model and using ND5 and SS7 locomotives to tow empty and heavy trucks of different qualities as computational conditions respectively, the third argument of energy-saving operation of trains is analyzed and demonstrated and the essence of its establishment is revealed.