On the railways at that time, a locomotive pulled passenger train-cars typically, and it was planned for the 'Bullet trains' as well that a method of combining an electric locomotive and a steam locomotive should be used.
当時の鉄道はまだ機関車が客車を牽く方式が一般的で、「弾丸列車」も電気機関車と蒸気機関車を併用する方式で計画された。