Along with the above remodeling, withdrawal of seats or the introduction of bench-seats for existing cars was implemented, and all Kuroha 69 and Kuha 68 cars became Kuha 55, except for Kuroha 69001 and 002 that were transferred to the Yokosuka Line in 1942 as second-class cars (they were later transferred to the Chuo/Sobu Local Line for the purpose of transporting the prince to the Chiba Army Tank School).
これらの改造と並行して、既存の車両の座席撤去、ロングシート化も推進され、1942年に横須賀線用（後には宮様の千葉陸軍戦車学校通学に伴い中央・総武緩行線に転属）の2等車として転出したクロハ69001,002を除くクロハ69、クハ68の全車がクハ55に編入された。