Japan Railway & Transport Review 42 • December 2005

Breakthrough

Breakthrough of Japanese Railway

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Breakthrough of Japanese Railway 1

Progress of Electric Railways in JapanTeruo Kobayashi

Current State of Electric

Railways in Japan

In 2001, railways in Japan carried 21.79billion passengers (25.1% of all passengertransport) or 384.5 billion passenger-km(27% of all passenger transport). Railfreight totalled 59 million tonnes (1.0% ofall freight transport) or 22.2 billion tonne-km (3.8% of total), clearly indicating thatJapanese railway operators are almostexclusively passenger companies.Following the 1987 privatization anddivision of Japanese National Railways(JNR), railways in Japan are now composedof the six passenger operators and JR Freightin the JR group plus as other public andprivate railway operators.Table 1 to 4 show that Japanese railwaysare principally passenger railways and themajority of l ines use EMUs, withcompanies in the JR group using both DCand AC electrification methods and otherprivate railway companies using DCelectrification only.Today’s operations by the JRs started withtransport in the large cities and thenprogressed to electrification of main linesbetween major cities and the opening ofshinkansen high-speed railway links; theother private and public rai lwaycompanies handle transport in and aroundthe larger cities. Moreover, the lownumbers of locomotives is due to thebetter suitability of EMUs for passengerand high-density operations in the majorcities. Electrification technologies inJapan started with tramway operations andthen developed into DC electrification ofcity operations. The major changeoverpoint occurred in 1955 on the JNR SenzanLine when it was converted to single-phase AC using the commercial electricitysupp ly. Subsequen t ma in - l i neelectrification saw widespread adoptionof AC, which was also adopted at the 1964opening of the Tokaido Shinkansen. Thisarticle describes the development ofelectrification technology in Japan from

the dawn of railways to today’s shinkansenhigh-speed railways and the progress inpower technologies required forsuccessful electric operations.

Start of Railway Electrification

in Japan

Railways in Japan started with the 1872opening of the 29-km line built by underthe guidance of British engineers betweenTokyo and Yokohama—the gateway portto Japan in those days. Early railwayconstruction and operations were theresponsibility of the Railway Bureau of theMinistry of Public Works. Railwayconstruction started throughout the nationbut a large number of new lines werebeing built by private investors. In 1893,the Railway Bureau became the RailwayAgency and the 589-km line betweenTokyo and Kobe was opened in 1899 asthe nation’s main rail artery. Other mainlines were being built in rapid successionby private companies and the length ofprivate lines was soon three times that ofgovernment lines; many private lines werealso offering better speeds and servicesthan the government railways. In 1895,

the year before railway nationalization,the government railways covered2413 km while the private railwaysreached 5231 km.After the Russo–Japanese War (1904–05),the railways were soon making a majorcontribution to Japanese politics and theeconomy but there were increasing calls,especially from the military, for railwaynationalization. The passage of theRailway Nationalization Law in 1906 sawthe start of railway nationalization whenthe government purchased 4800 km oflines belonging to the 17 private railwaycompanies transferring 48,000 employeesand 25,000 pieces of rolling stock to thepublicly owned government railways.Japan’s first electric railway was openedin May 1890 when Tokyo Electric LightCompany built a 400-m track (1372-mmgauge) at the Third Industrial Expositionin Ueno Park, Tokyo where they operatedtwo tramcars imported from J. G. Brill &Co. of the USA. The first genuinelycommercial operations started in 1895when Kyoto Electric Railway startedoperating four tramcars using a 500-Vtrolley pole system in Kyoto City withhydroelectric power generated by water

Table 1 Electrified Operation-km of JR Group Companies in March 2003

Operation-km DC km AC km Electrification

Conventional lines 17,857 6280 3,662 55%

Shinkansen 2,249 � 2,249 100%

Table 2 Electric Rolling Stock of JR Group Companies

Electric locomotives EMUs Total

Conventional lines 780 21,719 22,499

Shinkansen � 3,731 3,731

Table 3 Operation-km and DC Electrified Operations of Private Railways

Operation-km DC Electrified km Electrification

Railways 7,108 5,088 71%

Tramways 482 475 99%

Table 4 Electric Rolling Stock of Private Railways

Electric locomotives EMUs Totals

Railways 119 25,649 25,768

Japan Railway & Transport Review 42 • December 2005 63

carried by canal from Lake Biwa. A fewyears later, electric operations started overa 2.3-km line in Nagoya City using powersupplied by a coal-fired power station.Tram ordinances promoted electrificationof city tramway operations and the firststeam railway to be electrified was the10.9-km line operated by Kobu Railwaybetween Iidamachi and Nakano in 1904.This section was purchased by theMinistry of Railways as part of the 1906nationalization to become the firstelectrified section of the governmentrailways.

Single and multiple overheadlinesThe early electric operations used carswith either one or two trolley poles. Inmodern electric railways, the negativecurrent (return) flows back to the powersubstation via the rails but at that time,the return current was returned to thesubstation via the overhead line. Sincecommunications lines in those days useda single wire, this overhead return wasused to prevent railway earth leaksinterfering with communications and alsoto prevent electrolytic corrosion ofunderground structures caused by leakagecurrent. In 1899, a special working groupdecided on future use of multipleoverhead lines for any suburban electricrailway and the start of Kobu Railway tramoperations used two trolley poles.However, the multiple overhead line

method had a complex structure andmade it difficult to achieve fasteroperations speeds so the single overheadline method was investigated and by1911, electric carriages were runningusing this method.

Power supplies and overhead linevoltagesToday, Japan’s national power grid usestwo frequencies; 60 Hz in the east and50 Hz in the west, with the border at theRiver Fuji near Mt Fuji on the main islandof Honshu. The historic reason is becausegeneration equipment was importedseparately from Europe and the USA.Unlike today, in the early days of electricrailway operations, commercial powerfrom the national grid was not used andthe railway companies built their ownpower stations and the generated powerwas then transformed to the 600-V supplyused by railcars. Some generation stationsused hydroelectric power but most werethermal stations generating power fromcoal. The power transformation from ACto DC was done using rotary convertersbut since the technology of the day maderectification of commercial frequenciesdifficult, a 25-Hz rotary converter wasused and the railway power stationssupplied power at a frequency of 25 Hz.A s a c o n s e q u e n c e , d e d i c a t e dhydroelectric power stations generatingpower at 25 Hz were built to supply powerto tram lines and railways in Tokyo.

Railway Nationalization and

Railway Agency

Railway Agency WorkingCommitteeFollowing the 1906 nationalization, in1908, responsibility for administration ofrailways was transferred from the Ministryof Communications to the RailwayAgency, which was part of the cabinet,and this administration system continueduntil 1987 when JNR was privatized anddivided. The first Director-General of theRailway Agency was Shimpei Goto(1857–1929) who had been appointed thefirst President of the South ManchuriaRailway in 1906.In 1910, Goto established the RailwayAgency Working Committee to deal withthe enormous expans ion in thegovernment railways caused by purchasesresulting from the Railway NationalizationLaw. This committee had 17 sub-committees. The avowed purpose ofnationalization was to streamline railwaymanagement and operations; increasetransportation capacity; promulgate theascendancy of manufacturing; planrailway infrastructure; cut administrativecosts; and reduce transportation charges.The second sub-committee of thecommittee was responsible for mattersrelated to track gauge; until then trackshad been laid to the narrow-gaugestandard (1067 mm) and this sub-committee examined whether or not to

JNR-designated Railway Memorial Nade 6141 electric railcar (two trolley poles)(JR East Oi Workshop)

Rotary transformers(Tokyo–Yokohama Electric Plant Memorial Photograph Album by Railway Bureau)

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Breakthrough of Japanese Railway

recommend a change to standard gauge(1435 mm). The opening of the Tokaidoand the San’yo main lines had alreadyseen discussion about the advisability ofchanging to standard gauge and in 1911,the government established the so-called‘Standard Gauge Railway UpgradeCommittee’ to compare the standard andnarrow gauges, and examine theeconomic effects of standard gauge andwhether it should be adopted for thenational railways network. However, dueto the massive costs of reconstructing theexisting narrow-gauge network tostandard gauge, it was decided to putpriority on new constructions, a situationthat remained unchanged until 1964when the Tokaido Shinkansen was openedrunning on standard gauge. In addition,sub-committee 13—the motive powersub-committee—was responsible fordiscussing plans for railway electrification,electrification methods and hydroelectricpower generation and the results saw theplanning and start of electric operationson Tokyo’s Yamanote Line.

Shin’etsu Line and Usui PassThe Shin’etsu Line links Tokyo withNiigata, the gateway port to Japan on theSea-of-Japan coast. It was an importantline for transporting agricultural produce,fish, and petroleum from Niigata to theTokyo metropolitan region. However, the11.2-km section between Yokogawa andKaruizawa stations crosses the Usui Passwith a steep grade of 66.7 per mill (1:15)rising and falling 553 m over 26 steeplyinclined sections. Steam operations usingan Abt rack-and-pinion system started in1893 but the speed of 7.5 km/h meant that75 minutes were required to cross the passand this section was seen as a candidatefor urgent electrification. The start ofelectric operations in 1912 saw thejourney t ime drop 75 minutes to43 minutes. To supply the requiredelectric power, a coal-fired power stationwith three generators each supplying

1000 kVA was built along with 6.6-kVpower lines and two substations totransform the power to 650 Vdc usingrotary transformers. A third rail suppliedthe electric locomotives. Interestingly,there were storage batteries (total of1332 Ah) at the substations that were usedto compensate the output of the rotarytransformers when trains were climbingthe grade and to store power producedby regenerative braking when trains wererunning downgrade. At that time, use ofstorage batteries in substations was quitenormal and could still be a very goodtechnology for confronting energyproblems today.The generators, generation equipment andelectric locomotives were all importedfrom Europe and the USA. However, thesubsequent construction of a gravity-fedoil pipeline parallel to the tracks betweenKaruizawa and Yokogawa making use ofthe difference in elevation saw the linestruggle economically due to decreasingfreight levels and the section was finallyclosed in 1997 to become part of anImportant Cultural Property after theopening of the Hokuriku (Nagano)Shinkansen.

Tokyo (Central) StationThe 1906 railway nationalizationpresented the opportunity to move theterminus at Shimbashi Stat ion inShiodome to the new Tokyo (Central)

Station completed in 1914. The newstation had four platforms serving 8 lines;two platforms and four lines servedTokyo’s urban lines and the Tokyo–Yokohama line, while the other platformsserved the Tokaido main line. At the timeof the station opening, the 22-km sectionbetween Shinagawa and Yokohama hadbeen electrified but the overhead doubleline system used previously had beenchanged to the overhead single linesystem electrified at 1200 Vdc. TheTokyo–Shinagawa section used theGerman 60-m compound catenary methodof Siemens while the Shinagawa–Yokohama section used the American45-m simple catenary method of OhioBryce. The electrifications works werecompleted in December 1914 and electricoperations started from 20 December.However, due to poor work and lack ofexperience with the new technologies,operations were switched back to steamfrom 26 December and electric operationswere delayed for a further 6 months. Thefirst pantographs used the roller methodbut soon changed to the slip-plate methodstill used today. Electricity (DC) waspurchased from Tokyo Railway operatingelectric tramways in inner Tokyo and alsofrom electric utilities but there wereproblems of price and since the frequencyof the utility power was 50 Hz, thegovernment railways built their ownpower station at Yaguchi on the Rokugo

Usui Pass (Electrification Works on Shin’etsu Main Line (1912) by Railway Bureau)

Japan Railway & Transport Review 42 • December 2005 65

River using engines powered by city gasto generate 6000 kW at 25 Hz, as well astransformer substations next to the tracks.This marked the start of genuine electricrailway operations in Tokyo.

Securing Power Supplies

Electrification InvestigationCommittee and power companyFollowing the end of WWI, railwayelectrification became the subject ofintense debate as a means of securing thenation’s rapidly growing transport needs.The E lect r i f ica t ion Inves t igat ionCommi t tee es tab l i shed in 1919recommended electrification of 4100 kmof lines and securing sufficient generationcapacity for transport became animportant issue in developing the plans.It was decided, ‘In principle andirrespective of whether power ispurchased from power utilities or obtainedfrom a government railways’ powercompany, it must be both inexpensive andhigh quality. Moreover, consideration willhave to be given to the performance ofprivate power utilities as well as todevelopment of government railways’own power companies.’ In concreteterms, this meant examining plans to builda hydroelectric power station to save coal,the main fuel at that time.At a cabinet meeting in July 1919, it wasdecided to economize on the usage ofcoals for government railways’ operationsand a plan was proposed to secure powerfor the railway operations in Tokyo bybuilding a hydroelectric power station

utilizing the flow of the River Shinano.The plan called for construction of astation producing 11,700 kW at Ojiyawhere the main river drops 100 m in ashort stretch. In the following year, theGovernment Railways Power CompanyLaw was proposed to establish a public–private power generation company butalthough the proposal was passed by theHouse of Representatives of the JapaneseDiet, discussion was shelved by the Houseof Peers. The first aim of the plan was tosecure power for the government railways’electrification by building a public–privatepower company that would supply anysurplus power to other railways andbusinesses. The existing private poweruti l i t ies were worried about thiscompetition from a new business andpetitioned the government to reject theidea of selling any surplus, leading to theplan’s abandonment. The plan for thehydroelectric power station called forconstruction to start in October 1920 butthe financial impact of the 1923 GreatKanto Earthquake on the public pursecaused a temporary delay and in 1925 itwas decided to split the construction intofour phases to permit economies inconstruction costs and time for raisingfunds. Phases 1 and 2 called forconstruction of a power station at Senjufol lowed by the second stage ofconstruction at Ojiya during phases 3 and4. The Senju power station finally startedoperations in 1939.On the other hand, demand for electricpower was increasing rapidly followingthe 1923 electrification of 77 km on theTokaido main line between Tokyo and

Kozu, and the 1931 electrification of81 km on the Chuo main line betweenHachioji and Kofu. As a result, coal-firedpower stations were built in 1923 inAkabane and in 1930 in Kawasaki tostrengthen the electricity supply system.Furthermore, the Tenryu River wasexamined as a source of power for theelectrification of the Shizuoka–Nagoyasection of the Tokaido main line in theTo k a i a n d C h u b u r e g i o n s a n dresponsibility for development of powersupplies was shifted in 1952 to the ElectricPower Development Company Ltd.Electrification in the Kansai region startedwith examination of the Totsu River buthopes for developing it as a hydroelectricsource were abandoned in 1954.Subsequently, generation capacity wasstrengthened at the hydro plant on theRiver Shinano and the coal-fired plant inKawasaki with the former able to generate450,000 kW and the latter 550,000 kW.Currently, the power stations belongingto JR East supply about 60% of its annualelectricity needs.

Progress with electrificationWhen the cabinet decided in July 1919to economize on coal consumption, theRailway Electrification InvestigationCommittee had planned to electrify4100 km of lines, starting with 83 km onthe Tokaido main line between Tokyo andOdawara, 26 km on the Yokosuka Line,and 87 km on the Chuo main lineb e t w e e n H a c h i o j i a n d K o f u .Electrification started, but in terms ofresults, only part of the network, such ascity suburbs and graded sections was

Generators powered by gas engines at Yaguchi Power Station(Tokyo–Yokohama Electric Plant Memorial Photograph Album by Railway Bureau)

Hydroelectric power station on River Shinano (JR East)

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Breakthrough of Japanese Railway

being electrified. As part of the WWIIcontrols to strengthen military transportcapacity, some sections of private electricrai lways were purchased by thegovernment railways between 1943 and1944, giving a total of 19,620 operation-km of which 1315 km (6.6%) wereelectrified lines. Of these 1315 km,690 km were government railways’ linesand 625 km were purchased privateelectric railways.

Private and Public Railways

Electric railwaysWith the spread of electric trams servicesfrom the main cities into regional cities,not only tram services but also small andmedium size electric railways startedappearing to link urban railways withtourist regions. In the 1930s, there were3800 km of regional lines and 2060 kmof tramway lines forming the privaterailway network. Subsequently, the April1938 publication of the NationalMobilization Law and the Land TransportBusiness Coordination Law resulted intakeovers and transfers of the manyvarious private companies to form thebasis of the nine major private railwayoperators that exist today. Furthermore,the birth of the publicly owned Teito RapidTransit Authority in 1941 marked the startintegrated subway services in Tokyo nowoperating as the Tokyo Metro.

Electric lighting businessElectric railways need electricity toproduce motive power and the earlyrailways operated their own powerstations using coal or water to generateelectricity. Naturally this was supplied totheir railway operations but theyinevitably saw a business opportunity forsupplying lighting to trackside areas too.In addition to lighting, they also loanedindustrial electric motors to factories.Companies that started out getting the

bulk of their income from electric railwayoperations soon became relatively largeelectric lighting and supply utilities.Conversely, electric power utilities alsoentered the electric railway business.However, the small generation capacityof the railway companies in the hugeelectricity supply business meant that theycould not compete with the powercompanies and their electric lightingbusiness was soon consolidated with thatof the larger power utilities, leaving fivepowerful national companies at that time.The 1938 National Mobilization Law andthe National Electricity Regulations ofApril 1942 saw management of theelectric railways’ power generationbusiness (70 operators) pass to nine powerdistribution companies. Ever since then,the electricity business has beenindependently managed by the nineregionally divided power companies butrecent approval for liberalization of thegeneration market seems likely to lead tothe entry of new players.

Postwar Electrification

Following WWII, private railways werethe mainstay of electric operations whilethe government railways had still onlymanaged to electrify a few difficultsections and regions in and around themajor cities. The government lines wereexperiencing great difficulties with steamoperations due to the poor-quality postwarcoals. The need for electrification had tobe negotiated with MacArthur’s GHQ andwas commenced slowly during postwarshortages of food and materials.By 1947, 106.5 km of the Joetsu Line hadbeen electrified between Takasaki andMinakami (41.5 km) and between Ishiuchiand Nagaoka (65 km). A further 40 km wereadded by 1949 on the Ou Line betweenFukushima and Yonezawa, followed by130 km in 1951 on the Tokaido main linebetween Numazu and Hamamatsu.

However, the urgently desired plan for fullelectrification of the Tokaido main line allthe way between Tokyo and Kobe wasopposed by the Civil TransportationSection (CTS) of GHQ and work was notstarted until the signing of the 1951 SanFrancisco Peace Treaty. It was completed10 years later in 1961, taking 46 yearssince electrification was first proposed and35 years since the first work started.During this early postwar period, thegovernment railways established theRailway Electrification Committee inSeptember 1947 that drew up a plan toelectrify a total of 1849 km of main lines.

AC Electrification

Reports about the postwar success of theFrench National Railways (SNCF) inelectrification using commercial single-phase AC power were soon heard and theJNR President Sonosuke Nagasaki visitedFrance in 1953 to study the potential ofAC electrification, resulting in theformation of the AC ElectrificationInspection Committee on his return toJapan (see JRTR 27. pp. 32–39). This wasthe start of AC electrification technologyin Japan, which would be subsequentlyadopted for the Tokaido Shinkansenopened in 1964. Compared to DCelectrification, the voltages used in ACelectrification are an order of magnitudehigher, so the distances between tracksidetransformer equipment can be muchlonger, which might be expected toreduce the number of ground facilities.However, for rolling stock using DCmotors, a rectifier is needed to transformthe AC to DC. Similarly, for rolling stockusing AC motors, a voltage–frequencycontroller is required.In 1951, SNCF engineers successfullycompleted development tests on a sectionof the Annecy Savoie Line, which theyreported at an international meeting in1952. This ‘Nancy Report’ led to the

Japan Railway & Transport Review 42 • December 2005 67

establishment of the AC ElectrificationInvestigation Committee in 1953.The committee minutes concluded that,‘Since it will be difficult to immediatelystart building AC electric locomotives inJapan, it would be advisable to conducttest runs using imported locomotives onthe Senzan Line and to start testproduction of main equipment with aview to building a base for futuremanufacturing. Furthermore, prototypingof domestically manufactured AC electricmotors and mercury rectifiers forreplacement of DC motors must be startedalong with simultaneous trial productionof transformers and controllers, etc., andpreparation of two test cars. Two units ofone class of the most diff icult todomestically manufacture electriclocomotives for which manufacturinglicenses can be obtained will be imported.We have confidence in domesticmanufacture of mercury rectifiers forroll ing stock so mercury-recti f ierlocomotives will be trial manufactured inJapan.… If there is no hope of importingAC electric locomotives, there seems littlechance of importing test locos unless wecan guarantee an order of 10 to 15 units.But if there is a chance, we have given anintermediary carte blanc to purchase oneunit each of an AC electric locomotiveand a mercury rectified locomotive fromFrench National Railways.’In 1955, SNCF successfully completed thefirst genuine AC electrification over a363-km section between Valencienne andThionville in northern France andrepor t ed the r e su l t s t o the ACElectrification International Conferenceheld in Lille that year. Japan sent fivedelegates and when the conferencefinished, they unsuccessfully attempted tonegotiate the purchase of two electriclocomotives.At the same time, tests were beingconducted over a 23.9-km sectionbetween Kitasendai and Sakunami on theSenzan Line; four types of locomotives

were built and tested using both mercuryrectifiers to convert AC to DC to drive DCmotors and direct AC motor drives. Theresults demonstrated the excellence ofusing mercury rectifiers and formed thebasis of new electric carriages to be usedwith subsequent AC electrification.Testing started in September 1954 and ranuntil March 1956.Japan’s first AC electric operations starteda year later in 1957 over a 46-km sectionof the Hokuriku main line betweenMaibara and Tsuruga.A feature of AC electrification is that sincehigh voltages of 20–25 kV are supplied tothe trolley wire (compared to 1500 V forDC), large cost savings can be achieveddue to the fewer on-ground substations atwider intervals compared to DCinstallations. Moreover, since there is lesswheel slip when starting, the traction force

is higher so lighter smaller locomotivescan haul heavier loads. In addition, sincethe pantograph collection current issmaller, high-speed operations are moreeasily achieved. As a consequence, ACelectrification became the favouredmethod for the Tokaido Shinkansen whenit opened in 1964.This early electrification work formed thebasis for a l l subsequent ra i lwayelectrification in Japan. In concrete terms,AC electrification is achieved by using aScott transformer to adjust voltageimbalances in the three-phase power fromthe power utility to provide a single-phaseload. Boosting transformers (BT) with awinding ratio of 1:1 are installed every3 to 4 km along the trackside to reduceinductive interference in communicationlines caused by earth leakage current byabsorbing return current (Fig. 1).

AC Electrification of Senzan Line using ED44 Electric Inspection Car (JNR Centennial Photo History)

Figure 1 BT Feeding System

3 to 4 km

Boosting transformer

Negative feeder

Contact wire

Rail

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Breakthrough of Japanese Railway

Tokaido Shinkansen

The Tokaido Shinkansen was opened inOctober 1964. Prior to that time, Japanesee l e c t r i c o p e r a t i o n s h a d b e e npredominantly DC on narrow-gaugetracks so the Tokaido Shinkansen heraldeda new era of high-speed operations on AC-electrified standard-gauge tracks.To achieve high operations speeds, oneshinkansen train set requires about10,000 kW of power, which meantdeveloping various new technologies forpickup currents in excess of 1000 A.First, for the pantograph to collectsufficient current from the catenary, sixpantographs were installed on one trainset and a compound catenary composedof contact wire, auxiliary catenary andmessenger wire was used. To prevent wirevibration due to the action of thepantograph, many hangers with a dampereffect were inserted close to the overheadwire supports. However, this methodexperienced a large number of faults dueto wire vibrations caused by increases inthe number of shinkansen running at veryshort headway. The present overheadwire structure uses a contact wire with athicker cross section and a higher wiretension. In addition, use of a high-voltagebus running between pantographs haspermitted the latest 16-car shinkansentrain sets to collect sufficient powerthrough just two pantographs.Second, al though the old BT ACelectrification of conventional lines couldbe used at 25 kV, since a single shinkansentrain set has a current load of 1000 A,some new technology was required.Using BT at 3-km intervals to suppressinduced interference in communicationslines resulted in a great amount of arcingat pick-up slip plates; this was controlledby inserting serial capacitors in thenegative feeder. However, such acomplex overhead structure resulted in anumber of overhead wire accidents and

the problem was finally solved bydevelopment of the auto transformer (AT)feeding method, which does not requireboosting transformers.Third, to prevent shorts between sectionsusing different power supplies resultingfrom feeds from different substations, onconventional lines, the driver sets thehandle notch to off and back on again.Since the driver of a high-speedshinkansen could never do this, tracksidepower supply auto-switching wasdeveloped to automatically switch powersupplies when passing between sections.These technologies were developed aspart of the 1950 AC electrification testson the Senzan Line and subsequentexperience of full-scale commercial ACoperations on the Hokuriku main linebefore being perfected as the shinkansenelectrification system.Since the Tokaido Shinkansen runsbetween Tokyo in the 50-Hz region andOsaka in the 60-Hz region and 60-Hz in-carriage electrical equipment wasadopted to lighten weight, two frequencyconversion stations were built in the50-Hz shinkansen operations region.Conventional AC electrified lines use20 kV because that was the voltagesupplied by the power companies at thattime but the shinkansen catenary isenergized at 25 kV.

Latest Shinkansen

Following the 1964 opening of theTokaido Shinkansen, transport demandgrew rapidly and the first 12-car train setswere quickly increased to 16 cars withabout 10 services running every hour.

H o w e v e r, t h e p r e s s u r e o n t h einfrastructure resulting from running8-pantograph train sets at a headway of6 minutes caused a number of problemsdue to wire vibration. At the time, theeasiest solution was to suppress wirevibration by changing to a heavycompound catenary design using thickerwire at a higher mechanical tension.Since this made the catenary structureextremely complex in sections containinga BT, there were more wire accidents,resulting in the urgent need for an upgradesolution. The solution was developmentof the AT feeding method instead of theBT. The AT method was already in use at11 kV and 25 Hz on the New Haven Linein Connecticut, USA, but had not beentes ted us ing commerc ia l powerfrequencies. In the AT method, the feederline and contact wire are linked by asingle-winding transformer, and theneutral point is connected to the rail.Since the substation feed voltage is twicethe overhead wire voltage, the intervalbetween substations is much longer thanthe BT feeding system and the groundinfrastructure can be simplified. However,there is a problem with voltage drops dueto the insertion of the AT single-windingtransformer but the great merits of thesimple structure and the elimination ofsections containing BTs made adoption ofthe AT method very attractive. Simulationof AT feeding circuits was started in 1964and after proof-of-technology tests onsome narrow-gauge lines, it was adoptedcommercially over the 259-km sectionbetween Yatsushiro and Nishi Kagoshima(now Kagoshima Chuo) on the Kagoshimamain line in October 1970. Subsequently,this method became the standard AC

Figure 2 AT Feeding System

10 to 15 km

Auto transformer

Feeder

Contact wire

Rail

Japan Railway & Transport Review 42 • December 2005 69

electrification technology in Japan whereit was adopted for both conventional andshinkansen lines—it also became thestandard method of AC electrificationoverseas. Due to increases in demandand aging infrastructure on the TokaidoShinkansen, the old BT feeding methodwas replaced by reconstruction to the ATmethod and as soon as all the old BTsections were eliminated, operationsspeeds were increased to 270 km/h fromthe original 210 km/h (Fig. 2).In addition, although the thick, high-tensile strength contact wire of thecompound catenary developed in Japancontinues in use, a new contact wiredesign was adopted on the 117-km sectionof the Nagano Shinkansen betweenTakasaki and Nagano opened in 1997, onthe 96-km extension of the TohokuShinkansen between Morioka andHachinohe opened in 2002, and on the137-km first southern section of theKyushu Shinkansen between ShinYatsushiro and Kagoshima Chuo openedin 2004. This new contact wire has acopper-clad steel core, providing a highwave propagation velocity and permittingconstruction of a simple catenary structurewith high-tensile strength; R&D into newcatenary structures is still continuing.The move to increased operations speedsdepends on the section in question but

the maximum is about 300 km/h. Sometest sets have recorded speeds of430 km/h.The Japanese shinkansen have all beenconstructed to standard gauge but toimprove access to the conventional linesof regional cities, tests were made onoperating shinkansen through services byupgrading narrow-gauge lines to standardgauge. This resulted in the recent openingof the 148-km Yamagata mini-shinkansen(1993) linking Shinjo with FukushimaStation on the Tohoku Shinkansen, and the127-km Akita mini-shinkansen (1997)linking Akita with Morioka also on theTohoku Shinkansen.

Summary

Looking at the history of railwayelectrification in Japan, most technologyin the Meiji period (1868–1912) wasimported and copied but then the trendsoon moved towards electric operationsusing domestic technology. Privaterailways took the lead over governmentrailways in introducing urban electric railservices and during this period, electricityfor operations was supplied from therailway companies’ own generatingstations with surplus capacity sold totrackside housing and factories. However,the railway companies’ electricity supplybusiness disappeared due to severe costcompetition with the larger power utilitiesand because wartime governmentregulations forced transfer of generationcapacity to the utilities. Electric railoperations continued growing and the

early postwar period saw promotion ofmain-line electrification by the newlyformed JNR due to severe postwar coalshortages hampering steam operations.The major turning point came with SNCF’ssuccess in using commercial single-phaseAC power for rail operations whileJapanese electric railway companies werestill using DC electrification. On hearingabout SNCF’s success, JNR pushed aheadwith AC electrification of the Senzan Lineusing its own technical developments and,as a result of this experience, was able tointroduce AC electrification on the newTokaido Shinkansen when it opened in1964.In the early days, the BT feeding methodusing trackside boosting transformers wasadopted but was subsequently replacedby the AT feeding method using low-costsingle-winding auto transformers, whichbecame the standard AC feeder system forrailways around the world, includinghigh-speed lines. ■

Further ReadingRailway Electrification Organization, History of

Electric Railway Technology Developments,

December 1983 (in Japanese).

T. Kobayashi, History of Electric Railways in Japan,

Tetsudo Gengyosha, June 1966 (in Japanese).

S. Yamanouchi, If There Were No Shinkansen, Tokyo

Shimbun, December 1998 (in Japanese).

Japan Railway Electrical Technology Organization,

Railways and Electrical Technology, Vol. 14, 11

(in Japanese).

Simple Catenary on Nagano Shinkansen (RTRI)

Teruo Kobayashi

Dr Kobayashi was Executive Operating Officer in the Business Development Unit of Nippon Densetsu

Kogyo, Co., Ltd. until Novemeber 2005, and now Executive General Manager of JR East Japan

Information Systems. He joined JNR in 1970 after graduating in Communication Engineering from

Tohoku University. He was manager of the Electrical Facilities Dept. at JR East and obtained a

doctorate in engineering in 1988. After leaving JR East in 2001, he joined the National Space

Development Agency of Japan (NASDA) before taking up his position at Nippon Densetsu Kogyo.