交通・運輸

論文一覧に戻る
交通・運輸

Technological Innovation and the Development of Transportation in Japan

論文タイトル: Chap. 7:Transportation in the Postwar Recovery Period (1946-1954): Railroads
著者名: Harada, Katsumasa
出版社: United Nations University Press
出版年: 1993
本論文の目次を見る本ページのPDF版を見る

Chap. 7:Transportation in the Postwar Recovery Period (1946-1954): Railroads


Recovery in Railroad Transport Power

The road of railroad recovery was a hard one. The shortage of labour and materials during the war had brought rolling-stock and equipment to the verge of collapse, and the bombing raids on the Japanese main islands brought almost complete destruction. When the war ended in August 1945, every railroad, national and private, had a very difficult time just running their trains. But the fact that the railroads continued running on the day of the surrender gave courage to those crushed with grief.
For people whose livelihood had been destroyed, the fact that the trains were running, even if they could not operate as they should, gave them a sense of the daily rhythm of life and an incentive to rebuild their lives.
Railroad employees worked under severe handicaps, with an awareness that people were expecting a great deal from them. The opportunity for railroad recovery was very important for the feelings of reliability between customers and employees and the sense of mission that arose out of that confidence.
Recovering from the pain of defeat required a great deal of effort and time. Restoring rolling-stock, equipment, and buildings required strength in manufacturing, a system of material supply, and the labour force. The lack of a supply of steel at the time prevented the replacement of rails that was so needed for operation. It was not until 1948 that the capacity to produce rolling-stock reached the prewar levels. Attention was given to upgrading manufacturing capability in order to produce locomotives and electric multiple units, and the old munitions factories were used at the maximum levels reached during the war for maintaining and repairing rolling-stock.
Private railroads operating electric trains in the vicinities of the large cities were particularly hurt by the shortage in rolling-stock and an inability to recover from damages. Many eventually had to adopt emergency measures in which they took over and repaired worn and damaged cars from the National Railways. However, private railways with the same track specifications as the National Railways were able to use rolling-stock manufactured for National Railway recovery, which later provided an opportunity to unify the specifications of the National Railways and private railroad commuter rolling-stock.
The Dodge Line, mentioned previously, put a severe damper on plans for rebuilding the National Railways and private railroads in 1948 and 1949, but the outbreak of the Korean War in 1950 changed the situation. completely. The war made imperative the quick transport of large amounts of men and materiel from Japan to the Korean War zone. The volume transported far surpassed the amount for Japanese units during any similar period of the Pacific War and was the largest military transport the National Railways had carried since its inception. For a time, the situation was one of extreme confusion at the munitions shipping stations near the port of Yokohama and at troop departure stations such as Sasebo and Moji, but if these shipments had not accelerated the speed of recovery, Japanese industry would not have been able to keep up with UN force requirements.
Under SCAP control, the National Railways moved forward in its plans for recovery, and despite the restrictions mentioned previously, progress was slowly being made on electrifying the railroads and introducing electric trains. The so-called Shonan trains that appeared in March 1950 on the Tokaido Main Line between Tokyo and Numazu violated conventional wisdom about electric trains in that the motors were distributed among the electric cars rather than being concentrated in one locomotive pulling the cars. These distributed-power commuter trains of 10 or more electric multiple units demonstrated their superiority to motive power concentrated in one locomotive. The Shonan trains are historically very significant because their success led to the expanded use of the distributed-power system in middle- and long-distance service, in high-speed express trains, and eventually in the Shinkansen plan.
Guidelines on similar forms of distributed power for diesel railcars were adopted in 1952. Research on internal-combustion engines had lagged behind that of other countries since before the Second World War. At the time of World War II, Japan still had not completed research on how best to use the internal-combustion, diesel locomotives received as reparations after the First World War, and so the research on these internal-combustion engines was still at an extremely low level when it was abandoned. Later, the importance of railroad electrification was keenly felt in the extreme post-World War II shortage of coal. Yet, many strongly advocated a programme for the introduction of internal-combustion engines for those areas that could not be electrified. Most internal-combustion engines used by the National Railways during the prewar period were fueled by gasoline, due partly to the lack of prowess in diesel technology. After the war, the use of diesel engines became a major objective, in part for reasons of catching up with the rest of the world in technical levels.
The project got fully under way in 1951 with the building of the first diesel locomotive in 1953, the DD 50, which could be coupled to cars at either end. This led to the eventual construction of a diesel-electric locomotive, which, when put into service, brought about the development of torque-converter-drive diesel multiple units and the subsequent adoption of torque drive as the standard for all diesel cars and locomotives. The first diesel locomotives and cars had engines of around 180 horsepower, which was inadequate; but during the 1960s, a 400-horsepower diesel engine was developed and internal-combustion locomotives and cars were put into service equipped with powerful engines. This allowed the use of low-smoke engines in non-electrified zones, first in passenger rolling-stock. From around the mid-1950s, low-smoke passenger trains were operating in many non-electrified zones. In 1960, diesel multiple units began to be used on express trains in the non-electrified areas of the trunk railroads.
Before the advent of the Shonan trains, Japan's electric car technology had been based on the nose-suspension motor. But research to change this succeeded in applying the flexible joint transmission and drive system during the latter half of the 1950s. Research on these applications to private urban railroads was well advanced, but the National Railways developed in 1957 a new high-performance electric car for electric commuter trains fixed at 10 units. With the placement of this train into service, the transmission and drive system could be applied to high-speed electric trains, and in 1958, a limited-express electric train was built for the run between Tokyo, Osaka, and Kobe that reduced the 7 hour and 30 minute transit time required by locomotive-powered trains to 6 hours and 50 minutes (later 6. hours and 30 minutes) between Tokyo and Osaka. That made possible one-day round trips between Tokyo and the Osaka-Kobe area.
Fig. 1. National Railway network before the high-growth period (1955)
The route to this point led through many accidents caused by the electric cars designed during the war, and the enforcement of a thorough recovery during the years 1951-1953. Around this time the National Railways started a project to convert its wooden-bodied passenger coaches to steel. In several years' time all operating passenger coaches had steel bodies, and thus a large amount of rolling-stock had been fundamentally improved by the mid-1950s.
These improvements in rolling-stock were carried out from the mid-1950s and thereafter as a part of an active programme to modernize motive power. Express trains were restored to operation in 1949, the standard train schedule was gradually reinstated beginning in 1950, and, by 1953, the prewar levels in transportation had been reached. When the SCAP restrictions were rescinded, construction for electrification moved boldly forward on the trunk lines, with the entire Tokaido Main Line electrified by 1956.

Modernizing Locomotive Power and Technical Reform

To further the recovery, update equipment and rolling-stock, and promote the use of electrical and diesel power, in 1955 the National Railways adopted its first five-year plan (actually launched in 1957), which emphasized improvements in those facilities and equipment that had recovered least. Under the Occupation, the National Railways had been converted (on 1 June 1949) to a public corporation and provided with a budget independent of the government's. The National Railways was now in a position in which it had to rely on this five-year plan to rapidly strengthen transportation power and stabilize its management system.
The five-year plan did not, however, result in an adequate rehabilitation of worn equipment, which gives some indication of how much the equipment had been damaged during the war, but it was also a question of emphasis, for most of the improvements made during the five-year plan were those dedicated to rolling-stock performance. Efforts to increase the load that tracks could bear by increasing rail weight and improving rails and roadbed had still not produced adequate results. The use of alternating current as part of the programme to modernize motive power was planned to start in 1953. In 1957, the National Railways succeeded in using 50 hertz (60 hertz west of Fujikawa and Himekawa) commercial frequency, 20,000 V single-phase alternating current, a valuable contribution to reducing the number of substations and improving the operating efficiency for both trunk and local lines. The later technological success of the Shinkansen was due to the achievements made with the Shonan electric trains, the new performance electric trains, and the use of alternating current.
Table 1. Number of kilometres electrified and equipped with automatic signals along National Railway lines