为了适应鉄路运輸事业发展的需要,近年对新造YZ_(21)型車及YZ_1型車原設計上存在的一些缺点,进行了加装改造,經过改造后,虽然在强度使用性能等方面有了改善,但从再进厂检修車来看,还存在一些慣性质量問題,需予以消除。如側梁和窗楣部分的严重腐蝕,造成在进厂检修时須全部更換。 In order to meet the needs of the development of Kushiro transport business, in recent years, the new design YZ_ (21) car and YZ_1 car some of the shortcomings of the original design, retrofitting, after the transformation, though in terms of strength and other performance To improve, but from the factory inspection car into the point of view, there are still some problems of inertial quality, to be eliminated. Such as the side beams and lintel part of the serious corrosion, resulting in the repair into the plant must be replaced.