There has been significant upgrading of signalling and telecommunication facilities as various new technologies in the last half decade ,leading to considerable changes in maintenance methods.
JNR implemented several modernization progranis for maintenance until the task was taken over b~ the privatized JR companies in april 1987.
Primitive maintenance methods,for instance,changing bulbs after they fail. called breakdoun maintenance ",cannot meet the requirements of high-speed and high-frequency train operation.
(1) Preventive maintenance ",aiming to prevent the occurrence of failuers without affecting train operation through periodic inspections and other methods such as life span estimation.,has been introduced and gradually put into practice by JNR since the 1930s.
JNR adopted this overall concept in the first maintenance modernization program implemented in 1957. The historic data management method using record cards Karte", aiming for scientific control based on data instead of experience and intuition,was also introduced at the time.
(2) To cope with increasing train traffic and reform railway management, worsening due to rising labor costs, the second program involving the strengthening of facilities, revision of inspection periods and commissioning of maintenance work to outside companies..was implemented from 1968 through to 1972.
Although the efficiency of maintenance work improved with the second program, maintenance were still based on the concert of periodic inspection, possibly causing an increase in employee numbers as facilities increased. However rapid developments in system technology and reliability technology in railways,and the development of an inspection-car,automatic
