As the allocation of gasoline for use in cars was suspended during the war period, that being the so-called substitution era, charcoal-fueled cars and electric cars were used in place of gasoline cars, but their horsepower was substantially inferior to that of gasoline cars and Kumara Jidosha, which relied mainly on charcoal cars, barely continued its business while suspending the operation of the route for Kurama northward.
当時はまだ戦時中の自動車用ガソリン配給停止が続いており、いわゆる代用品時代で木炭車や電気自動車が代燃車として運行されていたが、いずれもガソリン車に比べて著しく力が劣っており、木炭車主体の鞍馬自動車は鞍馬以北の路線を停止してどうにか営業を続けていた。