JNR's Choice of Traction System—From Loco-Hauled to Multiple-Unit

Feature Evolution of Railway Technology

JNR’s Choice of Traction System—From Loco-hauled to Multiple-unit Trains Kenji Inayama

by making innovative changes to some Early beginnings Introduction existing railway technologies. The In the late 1940s, a number of railway innovations and improvements were engineers began suggesting that In Japan, most long-distance passenger reflected especially in rolling stock, railways should start long-distance trains use the distributed traction system track, electric power supply systems, express electric passenger services. with powered cars carrying passengers. and signalling. This article focuses on One proponent of this idea was Hideo By contrast, in Europe, the USA and one technical development adopted for Shima (1901–98) who later became elsewhere, loco-hauled unpowered the Tokaido Shinkansen—rolling stock. known as the father of the Tokaido carriages are dominant, although adapted As explained above, most long-distance Shinkansen. As WWII drew to a close, multiple units are being tested by some passenger trains are electrical multiple he began basic research in the field, railways. In other words, the motive units (EMUs). This is such an obvious hoping to play an influential role in power is dispersed among the cars of fact today that one might think that the developing high-speed, long-distance the train set. Japan’s high-speed trains shinkansen designers would have electric passenger services in Japan. are all EMUs while European high- chosen the EMU model right from the Within a few years of the war’s end, the speed trains are basically loco-hauled. start. However, when the shinkansen newly formed JNR began an ambitious The design concepts are very was being designed in the late 1950s, reconstruction plan and Shima’s vision different—the shinkansen is powered most long-distance passenger trains in was to develop efficient long-distance by electric motors mounted in multiple Japan, Europe, the USA and elsewhere electric passenger trains for the new locations, while the TGV and ICE use a were loco-hauled. Until the 1950s, the network. locomotive to haul unpowered cars. very idea of developing an EMU train However, electric trains of the day Japan’s Tokaido Shinkansen was was considered quite revolutionary. suffered from uncomfortable ride opened in October 1964 to increase So why did Japan choose the EMU as characteristics caused by vibration and passenger capacity in the Tokyo–Osaka the model for the shinkansen? The Shima established the High-speed corridor because the Tokaido main line most-commonly cited reasons are Bogie Vibration Study Group in had reached its limit. The new line had lighter axle load, better acceleration December 1946 to find a solution to a maximum operating speed exceeding and deceleration, better braking, and the problem. 200 km/h, the fastest in the world at better operating efficiency. These The group identified a number of that time. By dramatically increasing advantages were recognized as electric factors and subsequent research speed, Japanese National Railway (JNR) train technology improved. As a result, focused on development of vibration- boosted demand for rail travel and the EMUs were soon running longer free bogies. This development made it shinkansen became an important distances at high operating efficiency possible to develop high-speed long- revenue source for JNR just as its and JNR’s decision-makers realized the distance electric trains running on financial situation was deteriorating. good sense of using them for long- narrow-gauge track. The shinkansen was so successful that distance passenger services. This In 1948, Shima became Director it motivated countries like France and article focuses on the background General of the Rolling Stock & Germany to build high-speed railways. against Japan chose the EMU for most Mechanical Engineering Department in Before the shinkansen, pessimists had of its passenger trains. charge of rolling stock development. predicted a slump in rail travel with Soon after, the department published passengers flocking to planes and motor Requirements for Electrification of vehicles instead. The Tokaido The Series 80 Shonan Densha Japan’s Government Railways, setting Shinkansen proved them wrong and forth a long-term plan for high-speed opened the way to new possibilities in This section describes the development electric train development. The report railway development. The so-called of the Series 80 Shonan Densha, which indicated the intention to promote ‘bullet train’ revolutionized the idea of is generally regarded as the grandfather electrification for medium-distance high-speed rail travel. of long-distance, high-speed electric trains serving large urban centres and In addition to building the Tokaido trains in Japan because it established for long-distance trains on the Tokaido Shinkansen to boost capacity between the realization in JNR that the future of main line between Tokyo and Osaka. Tokyo and Osaka, a second reason was long-distance passenger rail travel lay This plan led to the development of the to create a new, high-speed rail system with electric trains. Series 80 Shonan Densha.

40 Japan Railway & Transport Review 27 • June 2001 Copyright © 2001 EJRCF. All rights reserved. Development background Electric locomotives were being used to haul local passenger trains (known as Shonan Trains) between Tokyo and Numazu (126.2 km southwest of Tokyo) on the Tokaido main line. In the late 1940s, rush-hour commuters were crammed into carriages and there was a strong desire to cut the overcrowding by increasing the capacity. The government railways began looking at ways to increase capacity and Shima pushed for introducing EMUs, saying that the more-efficient operations (faster turnaround, etc.) would increase capacity. There was some opposition because EMU trains vibrated excessively and ride comfort would be far too low for a run of more than 100 km. However, increased capacity won out against comfort and the decision JNR’s long-distance Series 80 Shonan Densha (S. Kubo) was made to electrify the system. Rolling-stock development began in 1948 and was completed in 1950. The responsible for developing passenger division to develop the motive power designers soon realized that the carriages and freight wagons. This parts, such as motors and bogies, and carriage interiors would need at least separation of responsibility may seem for the latter division to develop the the same standards of comfort as unusual because EMUs and loco- body and fittings. This overlapping conventional carriages hauled by hauled carriages both carry passengers. responsibility changed the course of locomotive on long-distance runs. It However, officials at government EMU development and underlines the was hoped that the new design would railways at that time saw EMUs as quite fact that the Series 80 was a unique type be adapted for high-speed, long- different from loco-hauled carriages of train for its day. distance services creating an because the respective design and incentive to produce advanced operations technologies were different. Evolution of Series 80 bodies and bogies. Assigning development of EMUs to the The first units of the Series 80 left the The new Series 80 EMU was to be division that developed locomotives works in January 1950 and almost quite different in operation and reflects how the government railways immediately began carrying passengers technology from the existing electric viewed EMUs at that time. on local services between Tokyo and trains and its development required Although the Series 80 was to be an Numazu in March. Although the EMUs different organizational arrangement EMU, at the same time, it would increased capacity as planned, from previous rolling stock. consist of passenger carriages. The passengers were subjected to frequent Responsibility for rolling-stock question was whether the Series 80 breakdowns. With hindsight, this is not development within the Rolling Stock should be considered electric power surprising because the technology was & Mechanical Engineering Department cars. If so, the Motive Power Unit new and trial runs had only been was divided between the Motive Power Division should develop them. Or conducted for a few weeks before the Unit Division and the Passenger and should they be considered passenger trains entered service. Freight Car Division. The former was carriages? If so, the Passenger and As a stopgap to relieve the problems, responsible for developing locomotives Freight Car Division should develop some commuter services were returned and EMUs, while the latter was them. The solution was for the former to loco-hauled trains. This gave the

designed specifically for high speeds and long distances—the Series 151 Kodama (Echo).

JNR Electrified limited express services In the mid-1950s, JNR was proceeding with electrification of the entire Tokaido main line (556.4 km) but the question remained about what type of train should be used for the fastest limited express services when the electrification was completed. Also, what should be done with the existing Tsubame and Hato loco-hauled limited expresses? Despite the advances in long-distance passenger services between Tokyo and Numazu demonstrated by the Series 80 EMU, JNR still held fast to the conservative idea that loco-hauled trains were best for long-distance and limited express services. Thus, limited Odakyu’s Series Deha 3000 SE Romance Car (S. Kubo) expresses on the Tokaido main line were still hauled by locomotives even railway time to improve the rolling Nagoya and Osaka (190.4 km). In October after the line was fully electrified in stock, and breakdowns were soon 1957, Series 80 EMU express services November 1956. occurring less frequently, proving that nicknamed Tokai (Tokyo–Nagoya) and Hiei In 1957, JNR decided to add new the new EMUs could offer services on (Nagoya–Osaka) were inaugurated. limited express trains to the Tokaido schedule. The newly established JNR The new EMU local expresses were main line. By then, electrification had was soon confident enough to begin soon running almost as fast as loco- reduced travel times between Tokyo running local-express services on hauled prestigious limited expresses and Osaka from 8 hours to 7 hours 30 weekends between Tokyo and Numazu on the same line. As soon as the minutes and JNR hoped to reduce it in October 1950. This was JNR’s first Series 80 was running long distances, further to 6 hours 30 minutes by EMU offering superior services. its potential was evident. The increasing maximum train speeds and However, although ride comfort on the development of the Series 80 led to a easing speed restrictions. But which type Series 80 local express was still inferior change of opinion at JNR. should be used for the new limited to that of loco-hauled trains, they were expresses—conventional loco-hauled much more flexible in operations terms, trains or EMUs? Shima and EMU leading to efficient services and greater Series 151 Kodama EMU advocates were convinced EMUs were customer satisfaction. EMU local- suited for new limited expresses but express services were first offered on a In the previous section, we saw that the some JNR officials remained seasonal basis and then on a regularly Series 80 EMU was developed to boost unconvinced. To reach a consensus, scheduled basis. capacity. When the EMU was first Shima established the Electrification By November 1956, the entire Tokaido developed, it was not intended to be Study Committee. The committee main line between Tokyo and Osaka fast long-distance train, but its concluded that EMUs were superior, had been electrified, setting the stage adaptability to high speeds and long offering various advantages, including for JNR’s plan to run Series 80 EMUs distances soon became apparent. lighter axle load, better acceleration, between Tokyo and Nagoya (366 km), By contrast, this section explains the better braking, and better operating connecting with similar trains between development and evolution of a train efficiency. The committee also noted

42 Japan Railway & Transport Review 27 • June 2001 Copyright © 2001 EJRCF. All rights reserved. that it was possible to reduce vibration voice strong opposition. But long- Kodama development history thereby ensuring a more comfortable distance high-speed EMU advocates led After JNR launched the Series 80, it ride. These conclusions led to the by Shima saw this as an opportunity to continued to develop some basic decision that the new limited express raise railway technology to higher levels technologies which later contributed to trains would be EMUs. JNR decided to and strongly urged JNR to agree to introduce high-speed long-distance introduce EMU limited express services Odakyu’s request. Their opinion was EMU services. The research into the on the Tokaido main line in autumn accepted and preparations began. potential of EMU limited expresses was 1958 and the train would be named the Speed tests were conducted in September conducted in tandem with development Kodama. The stage was set for 1957 on the Tokaido main line and the of Series 101 EMUs, which entered development of the Series 151. Odakyu SE achieved 145 km/h—a world commuter service in June 1957. record for a narrow-gauge train. The main Although the Series 101 was only built High-speed tests with Odakyu objective of the speed test was to gather for commuter services, it embodied a Electric Railway technical data on high-speed train travel, number of advanced features, including While considering what type of limited but it also demonstrated the advantages a small, light motor with a Cardan driving express train to develop, an opportunity of EMUs to JNR decision-makers. The device designed to achieve both speed arose that demonstrated the great establishment of the world narrow-gauge and ride comfort. After the High-speed potential of EMU trains. The private speed record by Odakyu’s Series 3000, Bogie Vibration Study Group was Odakyu Electric Railway was alongside the successful start of EMU established, car vibration was developing its Series 3000 Super express trains using Series 80, had a considerably reduced by mounting Express (SE) EMU to speed up services considerable impact on JNR’s decision to carriage bodies on air springs on bogies. between Shinjuku in Tokyo and introduce EMU limited express services. In 1955, JNR developed the Naha 10, Odawara (about 70 km southwest of JNR (RTRI) cooperated with Odakyu in a very light passenger carriage that Tokyo). The company believed that the developing SE technology. From one reduced axle load. The new technology best solution was an advanced viewpoint, JNR practically asked the and design were instrumental in EMU and needed to examine its much smaller private Odakyu to give it developing lightweight EMU carriages. performance during high-speed tests. the opportunity to verify the potential The new drive system, vibration- However, Odakyu had limited of fast long-distance EMUs. damped bogies, and lightweight technical resources, so it asked JNR’s Railway Technology Research Institute (RTRI) for help with developing the high-performance EMU. JNR agreed and a joint programme was established. The new SE train was unveiled in June 1957 with every part using the latest technologies of the day— it was lightweight; had a low centre of gravity; was articulated; was streamlined; and had a design speed of 145 km/h. However, when Odakyu ran speed tests on its own track, it could not push the train to the design speed because the track was curved throughout the entire length. Consequently, the company asked JNR to run speed tests on the Tokaido main line, which offered better test conditions. However, no private railway had ever tested rolling stock on government track and this lack of precedent caused some JNR officials to JNR’s limited express Series 151 Kodama (A. Hoshi)

carriage bodies were all incorporated EMUs as suitable for limited express addition, JNR decided to cut Tokyo– in the Series 151. When it left the services. Consequently, about 1 month Osaka journey times to 6 hours 40 works in September 1958, it was a high- was allowed before the Series 151 minutes in September. speed passenger EMU well suited to entered full commercial service. The avant-garde Kodama was very long-distance runs. Comfort was also Early plans called for the Kodama to popular and highlighted the further improved to limited express make the run between Tokyo–Osaka in obsolescence of the much older loco- levels by other new features, including just 6 hours 30 minutes, but a hauled Tsubame and Hato limited fixed windows, air conditioning and provisional schedule was introduced, express trains still in operation. As a upgraded lighting . allowing journey times of 6 hours 50 result, JNR began to consider minutes. The Kodama ride comfort and mothballing the old trains and replacing Delayed start ensures success shorter journey times earned a good them with new ones. But this gave rise JNR decided to put the Kodama into reputation and attracted high passenger to a difficult question— if JNR service in October 1958 as the main levels right from the start. Interestingly, mothballed the old limited expresses, attraction of a completely revamped other limited express services did not should it replace them with national timetable. However, it suffer a drop in passenger numbers, conventional loco-hauled trains or with actually entered service in November, indicating that Kodama was serving a EMUs? A decision was put off until the about 1 month behind schedule new market. success of the Kodama became clear. because construction was only The Series 151 EMUs had a maximum Meanwhile, development of a new completed in September, leaving schedule speed of 110 km/h although locomotive to haul limited express insufficient time for a complete set of the design speed was far higher at 160 trains was in planning. However, this test runs. km/h. To verify the train’s performance, tendency towards favouring loco- After its experience with the Series 80, JNR conducted high-speed tests in July hauled trains changed as Kodama JNR knew that if it put Kodama into 1959 in which it achieved a world proved its advantage and in June 1960, service on schedule with insufficient record for narrow gauge of 163 km/h, the old Tsubame and Hato were testing and the new train broke down proving the extent of JNR’s technical replaced by Series 151 EMUs with the frequently, passengers might not accept prowess in developing EMUs. In same names. Finally, EMUs were used for all daytime limited expresses on the Tokaido main line and Tokyo–Osaka journey times reached 6 hours 30 minutes. The Tokaido main line was JNR’s most important trunk line and limited expresses on this line were the most prestigious. In this sense, the Tokaido main line EMUs symbolized JNR itself and showed that the era of the EMU had truly arrived.

Progressive Evolution towards Tokaido Shinkansen

After developing the Series 151 Kodama, JNR built the Tokaido Shinkansen to increase capacity on the important Tokyo–Osaka route and to create a high-speed railway system. When constructing the shinkansen, JNR incorporated many technical innovations into the rolling stock, track, Trunk line electric car—Shinkansen (Transportation Museum) electric power supply systems,

44 Japan Railway & Transport Review 27 • June 2001 Copyright © 2001 EJRCF. All rights reserved. signalling, etc. Once again, Shima The whole process meant that even after H. Shima, Shinkansen soshite uchu kaihatsu (After played a leading role in formulating the long-distance EMU express services the Shinkansen, Outer Space), Railway System design concepts based on his belief that became technically feasible, it took some Research, 1987. an EMU system with a maximum more time for the JNR managers to reach M. Takabayashi, Tokaido Shinkansen sharyo no schedule speed of 210 km/h (now 270 a consensus for the extensive use of EMUs sekkei to zairyo (Design and Materials for Tokaido km/h) would be best because it offered for long-distance express services. Shinkansen Rolling Stock), Kinzoku, Vol. 33, No. the same advantages demonstrated by However, the resultant change in mindset 10, pp. 46–48, 1963. the earlier Series 80 and Series 151 soon led to the opening of the Tokaido R. Yamamoto, Kosoku kansetsu densha SE sha ni EMU. The final decision was much Shinkansen. I tsuite (The SE High-speed Articulated Electric Train), easier to make in technical terms due to Sharyo Gijutsu, No. 40, pp. 2–8, 1958. the experience with earlier EMUs and Further Reading Shima even remarked to a World Bank A. Hoshi, Kaiso no ryokyakusha joge (Passenger Trains official that the shinkansen techniques in Retrospect Vol. 1 & 2), Koyu-sha, 1985. included no experimental factor but M. Ishizawa, Shinkansen shisakusha e no sharyo were an integration of proven advanced gijutsu no shuseki (Development of Rolling Stock technologies achieved under the slogan Technology for a Shinkansen Prototype), JREA, Vol. Safety First. 5, No. 10, pp. 5–8, 1962. The last section of this article R. Kakumoto, Tokaido Shinkansen, Chuo Koron-sha, summarizes the EMU developments 1964. and then discusses how these T. Matsudaira, Kosoku tetsudo gijutsu no reimei (The developments point to some strategies Early Beginnings of High-speed Railway that a corporation can take when Technology), Railway Research Review, Vol. 50, No. introducing new technologies. 3, pp. 25–29, No. 4, pp. 28–34, No.5, pp. 27–32 1993. T. Miki, Odakyu 3000 kei SE sha sekkei no tsuioku Summary (Designing the Odakyu Series 3000 SE—A Retrospect), Railway Fan, No. 375, pp. 91–97, 1992. Development of the Series 80 prompted M. Saito, Bakushin (Ever Faster, Ever Better), Tetsudo the use of EMUs for longer-distance Journal-sha, 1999. commuter services (Shonan Densha) and S. Sawano, Chokuryu densha no sekkei ni tsuite (The local express services (Hiei and Tokai). Design of Electric Railcars), Sharyo Gijutsu, No. 83, The success of these trains showed that pp.1–6, 1963. EMU trains were well able to travel at high Shinkansen 10 nenshi, (The Shinkansen—Ten Years speeds over long distances. of History), JNR Shinkansen Sokyoku, 1975. By this time, some railway professionals H. Shima, D-51 kara shinkansen made: Gijutsusha were convinced that EMU local expresses no mita kokutetsu (From the D-51 to the could be adapted for long-distance, high- Shinkansen—An Engineer’s View of JNR), Nihon speed services and new technologies Keizai Shimbun-sha, 1977. such as air-spring bogies, light carriage bodies, Cardan driving device, etc., made development technically possible. Even so, JNR continued to operate older, loco- Kenji Inayama hauled limited expresses until a joint project with the private Odakyu proved Dr Inayama is a lecturer in the Faculty of Economics at Meiji Gakuin University. the potential of long-distance, high-speed EMUs. Still JNR was hesitant to replace existing limited express trains with EMUs until convinced by the success of it new Series 151 Kodama.