我国从六十年代起,先后生产了载重60吨的P_(13)、P_(60)及P_(61)型棚车。从1965年以后,车内顶板逐渐采用了纤维板。但是,从近年入段检修情况看,内顶纤维板丢失严重,少则几张,多则全车。这不但增加了检修工作量和材料费用,而且影响车体的使用寿命和性能。据统计,昆明段1980年段修 Since the 1960s, China has successively produced 60 tons of P_ (13), P_ (60) and P_ (61) box cars. Since 1965, the roof of the car has gradually adopted the fiberboard. However, from the overhaul conditions in recent years, the top of the fiberboard loss is serious, ranging from a few, as many as the entire car. This not only increases the maintenance workload and material costs, but also affect the life of the body and performance. According to statistics, Kunming section of 1980 repair