Breakthrough

Breakthrough of Japanese Railway

Breakthrough of Japanese Railway 1

Progress of Electric Railways in Japan
Teruo Kobayashi
Current State of Electric
Railways in Japan

In 2001, railways in Japan carried 21.79
billion passengers (25.1% of all passenger
transport) or 384.5 billion passenger-km(27% of all passenger transport). Railfreight totalled 59 million tonnes (1.0% of
all freight transport) or 22.2 billion tonnekm (3.8% of total), clearly indicating thatJapanese railway operators are almost
exclusively 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 railways
are principally passenger railways and the
majority of lines use EMUs, withcompanies in the JR group using both DC
and AC electrification methods and otherprivate railway companies using DC
electrification only.
Today’s operations by the JRs started withtransport in the large cities and thenprogressed to electrification of main lines
between major cities and the opening ofshinkansen high-speed railway links; theother private and public railway
companies handle transport in and aroundthe larger cities. Moreover, the low
numbers of locomotives is due to thebetter suitability of EMUs for passenger
and high-density operations in the major
cities. Electrification technologies inJapan started with tramway operations andthen developed into DC electrification ofcity operations. The major changeover
point occurred in 1955 on the JNR Senzan
Line when it was converted to singlephase AC using the commercial electricity
s u p p l y. S u b s e q u e n t m a i n - l i n eelectrification saw widespread adoptionof AC, which was also adopted at the 1964
opening of the Tokaido Shinkansen. This
article describes the development ofelectrification technology in Japan from62

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

Start of Railway Electrificationin JapanRailways in Japan started with the 1872
opening of the 29-km line built by under
the guidance of British engineers between
Tokyo and Yokohama—the gateway port
to Japan in those days. Early railway
construction and operations were theresponsibility of the Railway Bureau of the
Ministry of Public Works. Railway
construction started throughout the nation
but a large number of new lines werebeing built by private investors. In 1893,
the Railway Bureau became the Railway
Agency and the 589-km line between
Tokyo and Kobe was opened in 1899 as
the nation’s main rail artery. Other mainlines were being built in rapid succession
by private companies and the length ofprivate lines was soon three times that ofgovernment lines; many private lines werealso offering better speeds and services
than the government railways. In 1895,

Japan Railway & Transport Review 42 • December 2005

Table 1

Electrified Operation-km of JR Group Companies in March 2003

Conventional lines
Shinkansen

Table 2

Shinkansen

Railways
Tramways

Table 4
Railways

Operation-km

DC km

AC km

Electrification

17,857
2,249

6280
–

3,662
2,249

55%
100%

Electric Rolling Stock of JR Group Companies

Conventional lines

Table 3the year before railway nationalization,
the government railways covered
2413 km while the private railways
reached 5231 km.
After the Russo–Japanese War (1904–05),
the railways were soon making a major
contribution to Japanese politics and theeconomy but there were increasing calls,
especially from the military, for railway
nationalization. The passage of theRailway Nationalization Law in 1906 saw
the start of railway nationalization when
the government purchased 4800 km oflines belonging to the 17 private railway
companies transferring 48,000 employees
and 25,000 pieces of rolling stock to the
publicly owned government railways.
Japan’s first electric railway was opened
in May 1890 when Tokyo Electric Light
Company built a 400-m track (1372-mm
gauge) at the Third Industrial Expositionin Ueno Park, Tokyo where they operated
two tramcars imported from J. G. Brill &Co. of the USA. The first genuinely
commercial operations started in 1895
when Kyoto Electric Railway started
operating four tramcars using a 500-V
trolley pole system in Kyoto City withhydroelectric power generated by waterElectric locomotives
780

EMUs
21,719Total
22,499

–

3,731

3,731

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

DC Electrified km

Electrification

7,108
482

5,088
475

71%
99%

Electric Rolling Stock of Private Railways
Electric locomotives
119

EMUs
25,649Totals
25,768JNR-designated Railway Memorial Nade 6141 electric railcar (two trolley poles)(JR East Oi Workshop)

carried by canal from Lake Biwa. A few
years later, electric operations started overa 2.3-km line in Nagoya City using power
supplied by a coal-fired power station.
Tram ordinances promoted electrificationof city tramway operations and the firststeam railway to be electrified was the
10.9-km line operated by Kobu Railway
between Iidamachi and Nakano in 1904.
This section was purchased by the
Ministry of Railways as part of the 1906
nationalization to become the firstelectrified section of the government
railways.

Single and multiple overheadlines
The early electric operations used cars
with either one or two trolley poles. In
modern electric railways, the negative
current (return) flows back to the power
substation via the rails but at that time,
the return current was returned to thesubstation via the overhead line. Since
communications lines in those days useda single wire, this overhead return wasused to prevent railway earth leaks
interfering with communications and also
to prevent electrolytic corrosion ofunderground structures caused by leakage
current. In 1899, a special working groupdecided on future use of multiple
overhead lines for any suburban electricrailway and the start of Kobu Railway tram
operations used two trolley poles.
However, the multiple overhead line

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

method had a complex structure andmade it difficult to achieve faster
operations speeds so the single overheadline method was investigated and by
1911, electric carriages were running
using this method.

Power supplies and overhead line
voltages
Today, Japan’s national power grid uses
two frequencies; 60 Hz in the east and
50 Hz in the west, with the border at theRiver Fuji near Mt Fuji on the main islandof Honshu. The historic reason is because
generation equipment was imported
separately 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 own
power stations and the generated power
was then transformed to the 600-V supply
used by railcars. Some generation stations
used hydroelectric power but most were
thermal stations generating power fromcoal. The power transformation from AC
to DC was done using rotary converters
but since the technology of the day maderectification of commercial frequencies
difficult, a 25-Hz rotary converter wasused and the railway power stations
supplied power at a frequency of 25 Hz.
As a consequence, dedicatedhydroelectric power stations generating
power at 25 Hz were built to supply power
to tram lines and railways in Tokyo.

Railway Nationalization andRailway Agency
Railway Agency Working
Committee
Following the 1906 nationalization, in
1908, responsibility for administration ofrailways was transferred from the Ministryof Communications to the Railway
Agency, which was part of the cabinet,
and this administration system continued
until 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 Manchuria
Railway in 1906.
In 1910, Goto established the Railway
Agency Working Committee to deal withthe enormous expansion in thegovernment railways caused by purchases
resulting from the Railway Nationalization
Law. This committee had 17 subcommittees. The avowed purpose ofnationalization was to streamline railway
management and operations; increasetransportation capacity; promulgate theascendancy of manufacturing; plan
railway infrastructure; cut administrative
costs; and reduce transportation charges.
The second sub-committee of thecommittee was responsible for mattersrelated to track gauge; until then tracks
had been laid to the narrow-gauge
standard (1067 mm) and this subcommittee examined whether or not toJapan Railway & Transport Review 42 • December 2005

63

Breakthrough of Japanese Railway

recommend a change to standard gauge(1435 mm). The opening of the Tokaido
and 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 Upgrade
Committee’ to compare the standard andnarrow gauges, and examine theeconomic effects of standard gauge andwhether it should be adopted for thenational railways network. However, due
to the massive costs of reconstructing theexisting narrow-gauge network to
standard gauge, it was decided to put
priority on new constructions, a situationthat remained unchanged until 1964
when the Tokaido Shinkansen was opened
running on standard gauge. In addition,
sub-committee 13—the motive power
sub-committee—was responsible fordiscussing plans for railway electrification,
electrification methods and hydroelectric
power generation and the results saw theplanning and start of electric operations
on Tokyo’s Yamanote Line.

Shin’etsu Line and Usui Pass
The Shin’etsu Line links Tokyo with
Niigata, the gateway port to Japan on the
Sea-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 steeply
inclined sections. Steam operations using
an 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 candidate
for urgent electrification. The start ofelectric operations in 1912 saw thejourney time drop 75 minutes to
43 minutes. To supply the required
electric power, a coal-fired power station
with three generators each supplying

64

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

1000 kVA was built along with 6.6-kV
power lines and two substations totransform the power to 650 Vdc using
rotary transformers. A third rail supplied
the electric locomotives. Interestingly,
there were storage batteries (total of1332 Ah) at the substations that were used
to compensate the output of the rotarytransformers when trains were climbing
the grade and to store power produced
by regenerative braking when trains wererunning downgrade. At that time, use ofstorage batteries in substations was quite
normal and could still be a very goodtechnology for confronting energy
problems today.
The generators, generation equipment andelectric locomotives were all imported
from Europe and the USA. However, thesubsequent construction of a gravity-fed
oil pipeline parallel to the tracks between
Karuizawa and Yokogawa making use of
the difference in elevation saw the line
struggle economically due to decreasing
freight levels and the section was finallyclosed in 1997 to become part of an
Important Cultural Property after the
opening of the Hokuriku (Nagano)
Shinkansen.

Tokyo (Central) Station
The 1906 railway nationalization
presented the opportunity to move theterminus at Shimbashi Station in
Shiodome to the new Tokyo (Central)

Japan Railway & Transport Review 42 • December 2005

Station completed in 1914. The newstation had four platforms serving 8 lines;
two platforms and four lines served
Tokyo’s urban lines and the Tokyo–
Yokohama line, while the other platforms
served the Tokaido main line. At the timeof the station opening, the 22-km section
between Shinagawa and Yokohama had
been electrified but the overhead double
line system used previously had beenchanged to the overhead single line
system electrified at 1200 Vdc. The
Tokyo–Shinagawa section used theGerman 60-m compound catenary methodof Siemens while the Shinagawa–
Yokohama section used the American
45-m simple catenary method of Ohio
Bryce. The electrifications works werecompleted in December 1914 and electric
operations started from 20 December.
However, due to poor work and lack ofexperience with the new technologies,
operations were switched back to steam
from 26 December and electric operations
were delayed for a further 6 months. The
first pantographs used the roller method
but soon changed to the slip-plate method
still used today. Electricity (DC) was
purchased from Tokyo Railway operating
electric tramways in inner Tokyo and also
from electric utilities but there were
problems of price and since the frequencyof the utility power was 50 Hz, thegovernment railways built their own
power station at Yaguchi on the Rokugo

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

River using engines powered by city gas
to 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 Investigation
Committee and power company
Following the end of WWI, railway
electrification became the subject ofintense debate as a means of securing thenation’s rapidly growing transport needs.
The Electrification Investigation
Committee established in 1919
recommended electrification of 4100 kmof lines and securing sufficient generation
capacity for transport became an
important issue in developing the plans.
It was decided, ‘In principle andirrespective of whether power ispurchased from power utilities or obtained
from a government railways’ powercompany, it must be both inexpensive andhigh quality. Moreover, consideration will
have 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 build
a hydroelectric power station to save coal,
the main fuel at that time.
At a cabinet meeting in July 1919, it was
decided to economize on the usage ofcoals for government railways’ operations
and a plan was proposed to secure power
for the railway operations in Tokyo bybuilding a hydroelectric power station

Hydroelectric power station on River Shinano

utilizing the flow of the River Shinano.
The plan called for construction of astation producing 11,700 kW at Ojiya
where the main river drops 100 m in ashort stretch. In the following year, theGovernment Railways Power Company
Law was proposed to establish a public–
private power generation company but
although 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–private
power company that would supply any
surplus power to other railways andbusinesses. The existing private power
utilities 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 but
the financial impact of the 1923 Great
Kanto Earthquake on the public purse
caused a temporary delay and in 1925 it
was decided to split the construction into
four phases to permit economies inconstruction costs and time for raisingfunds. Phases 1 and 2 called forconstruction of a power station at Senju
followed by the second stage of
construction at Ojiya during phases 3 and4. The Senju power station finally started
operations in 1939.
On the other hand, demand for electric
power was increasing rapidly following
the 1923 electrification of 77 km on the
Tokaido main line between Tokyo and(JR East)

Kozu, and the 1931 electrification of
81 km on the Chuo main line between
Hachioji and Kofu. As a result, coal-fired
power stations were built in 1923 in
Akabane and in 1930 in Kawasaki tostrengthen the electricity supply system.
Furthermore, the Tenryu River was
examined as a source of power for theelectrification of the Shizuoka–Nagoya
section of the Tokaido main line in the
To k a i a n d C h u b u r e g i o n s a n d
responsibility for development of power
supplies was shifted in 1952 to the ElectricPower Development Company Ltd.
Electrification in the Kansai region started
with examination of the Totsu River but
hopes for developing it as a hydroelectric
source were abandoned in 1954.
Subsequently, generation capacity wasstrengthened at the hydro plant on theRiver Shinano and the coal-fired plant in
Kawasaki with the former able to generate
450,000 kW and the latter 550,000 kW.
Currently, the power stations belonging
to JR East supply about 60% of its annual
electricity needs.

Progress with electrification
When the cabinet decided in July 1919
to economize on coal consumption, theRailway Electrification Investigation
Committee had planned to electrify
4100 km of lines, starting with 83 km on
the Tokaido main line between Tokyo andOdawara, 26 km on the Yokosuka Line,and 87 km on the Chuo main line
between Hachioji and Kofu.
Electrification started, but in terms ofresults, only part of the network, such ascity suburbs and graded sections was

Japan Railway & Transport Review 42 • December 2005

65

Breakthrough of Japanese Railway

being electrified. As part of the WWII
controls to strengthen military transportcapacity, some sections of private electricr a i l w a y s w e r e p u rc h a s e d b y t h egovernment railways between 1943 and1944, giving a total of 19,620 operationkm of which 1315 km (6.6%) were
electrified lines. Of these 1315 km,
690 km were government railways’ lines
and 625 km were purchased private
electric railways.

Private and Public Railways
Electric railways
With the spread of electric trams services
from the main cities into regional cities,
not only tram services but also small andmedium size electric railways started
appearing to link urban railways with
tourist regions. In the 1930s, there were3800 km of regional lines and 2060 kmof tramway lines forming the private
railway network. Subsequently, the April
1938 publication of the National
Mobilization Law and the Land Transport
Business Coordination Law resulted intakeovers and transfers of the manyvarious private companies to form thebasis of the nine major private railway
operators that exist today. Furthermore,
the birth of the publicly owned Teito Rapid
Transit Authority in 1941 marked the start
integrated subway services in Tokyo now
operating as the Tokyo Metro.

Electric lighting businessElectric railways need electricity to
produce motive power and the earlyrailways operated their own power
stations using coal or water to generate
electricity. Naturally this was supplied totheir railway operations but they
inevitably saw a business opportunity forsupplying lighting to trackside areas too.
In addition to lighting, they also loaned
industrial electric motors to factories.
Companies that started out getting the66

bulk of their income from electric railway
operations soon became relatively large
electric lighting and supply utilities.
Conversely, electric power utilities also
entered the electric railway business.
However, the small generation capacityof the railway companies in the hugeelectricity supply business meant that they
could not compete with the powercompanies and their electric lighting
business was soon consolidated with thatof the larger power utilities, leaving five
powerful national companies at that time.
The 1938 National Mobilization Law and
the National Electricity Regulations ofApril 1942 saw management of theelectric railways’ power generation
business (70 operators) pass to nine power
distribution companies. Ever since then,the electricity business has been
independently managed by the nine
regionally divided power companies but
recent 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 while
the government railways had still only
managed to electrify a few difficult
sections and regions in and around the
major cities. The government lines wereexperiencing great difficulties with steam
operations due to the poor-quality postwar
coals. The need for electrification had tobe negotiated with MacArthur’s GHQ and
was commenced slowly during postwar
shortages of food and materials.
By 1947, 106.5 km of the Joetsu Line had
been electrified between Takasaki and
Minakami (41.5 km) and between Ishiuchi
and Nagaoka (65 km). A further 40 km wereadded by 1949 on the Ou Line between
Fukushima and Yonezawa, followed by
130 km in 1951 on the Tokaido main line
between Numazu and Hamamatsu.

Japan Railway & Transport Review 42 • December 2005

However, the urgently desired plan for fullelectrification of the Tokaido main line all
the way between Tokyo and Kobe was
opposed by the Civil Transportation
Section (CTS) of GHQ and work was notstarted until the signing of the 1951 San
Francisco Peace Treaty. It was completed
10 years later in 1961, taking 46 years
since electrification was first proposed and35 years since the first work started.
During this early postwar period, thegovernment railways established theRailway Electrification Committee in
September 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 singlephase AC power were soon heard and the
JNR President Sonosuke Nagasaki visited
France in 1953 to study the potential of
AC electrification, resulting in theformation of the AC Electrification
Inspection Committee on his return toJapan (see JRTR 27. pp. 32–39). This was
the start of AC electrification technology
in Japan, which would be subsequently
adopted for the Tokaido Shinkansen
opened in 1964. Compared to DC
electrification, the voltages used in AC
electrification are an order of magnitude
higher, so the distances between tracksidetransformer equipment can be much
longer, which might be expected toreduce the number of ground facilities.
However, for rolling stock using DC
motors, a rectifier is needed to transformthe AC to DC. Similarly, for rolling stockusing AC motors, a voltage–frequency
controller is required.
In 1951, SNCF engineers successfullycompleted development tests on a sectionof the Annecy Savoie Line, which theyreported at an international meeting in
1952. This ‘Nancy Report’ led to theestablishment of the AC Electrification
Investigation Committee in 1953.
The committee minutes concluded that,‘Since it will be difficult to immediately
start building AC electric locomotives inJapan, it would be advisable to conduct
test runs using imported locomotives on
the Senzan Line and to start test
production of main equipment with aview to building a base for future
manufacturing. Furthermore, prototypingof domestically manufactured AC electricmotors and mercury rectifiers for
replacement of DC motors must be started
along with simultaneous trial productionof transformers and controllers, etc., andpreparation of two test cars. Two units of
one class of the most difficult todomestically manufacture electric
locomotives for which manufacturing
licenses can be obtained will be imported.
We have confidence in domestic
manufacture of mercury rectifiers forrolling stock so mercury-rectifier
locomotives will be trial manufactured inJapan.… If there is no hope of importing
AC electric locomotives, there seems little
chance of importing test locos unless we
can guarantee an order of 10 to 15 units.
But if there is a chance, we have given anintermediary carte blanc to purchase one
unit each of an AC electric locomotive
and a mercury rectified locomotive from
French National Railways.’
In 1955, SNCF successfully completed thefirst genuine AC electrification over a
363-km section between Valencienne andThionville in northern France andreported the results to the AC
Electrification International Conference
held in Lille that year. Japan sent fivedelegates and when the conference
finished, they unsuccessfully attempted tonegotiate the purchase of two electric
locomotives.
At the same time, tests were being
conducted over a 23.9-km section
between Kitasendai and Sakunami on the
Senzan Line; four types of locomotives

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

Figure 1 BT Feeding System
Boosting transformer
Negative feeder
Contact wireRail
3 to 4 km

were built and tested using both mercury
rectifiers to convert AC to DC to drive DC
motors and direct AC motor drives. The
results 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 ran
until March 1956.
Japan’s first AC electric operations started
a year later in 1957 over a 46-km sectionof the Hokuriku main line between
Maibara 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 achieved
due to the fewer on-ground substations at
wider intervals compared to DC
installations. Moreover, since there is lesswheel slip when starting, the traction force

is higher so lighter smaller locomotives
can haul heavier loads. In addition, since
the pantograph collection current issmaller, high-speed operations are moreeasily achieved. As a consequence, AC
electrification became the favoured
method for the Tokaido Shinkansen when
it opened in 1964.
This early electrification work formed thebasis for all subsequent railway
electrification in Japan. In concrete terms,
AC electrification is achieved by using a
Scott transformer to adjust voltage
imbalances in the three-phase power fromthe power utility to provide a single-phaseload. Boosting transformers (BT) with awinding ratio of 1:1 are installed every
3 to 4 km along the trackside to reduce
inductive interference in communicationlines caused by earth leakage current byabsorbing return current (Fig. 1).

Japan Railway & Transport Review 42 • December 2005

67

Breakthrough of Japanese Railway

Figure 2 AT Feeding System
Auto transformer
FeederTokaido Shinkansen
The Tokaido Shinkansen was opened in
October 1964. Prior to that time, Japaneseelectric operations had been
predominantly DC on narrow-gauge
tracks so the Tokaido Shinkansen heralded
a new era of high-speed operations on ACelectrified standard-gauge tracks.
To achieve high operations speeds, one
shinkansen train set requires about
10,000 kW of power, which meantdeveloping various new technologies for
pickup currents in excess of 1000 A.
First, for the pantograph to collectsufficient current from the catenary, six
pantographs were installed on one train
set and a compound catenary composedof contact wire, auxiliary catenary andmessenger wire was used. To prevent wire
vibration due to the action of thepantograph, many hangers with a damper
effect were inserted close to the overhead
wire supports. However, this method
experienced a large number of faults due
to wire vibrations caused by increases in
the number of shinkansen running at very
short headway. The present overhead
wire structure uses a contact wire with athicker cross section and a higher wiretension. In addition, use of a high-voltage
bus running between pantographs has
permitted the latest 16-car shinkansen
train sets to collect sufficient power
through just two pantographs.
Second, although the old BT AC
electrification of conventional lines could
be used at 25 kV, since a single shinkansen
train set has a current load of 1000 A,
some new technology was required.
Using BT at 3-km intervals to suppress
induced interference in communicationslines resulted in a great amount of arcing
at pick-up slip plates; this was controlled
by inserting serial capacitors in thenegative feeder. However, such acomplex overhead structure resulted in a
number of overhead wire accidents and68

Contact wireRail
10 to 15 km

the problem was finally solved bydevelopment of the auto transformer (AT)feeding method, which does not require
boosting transformers.
Third, to prevent shorts between sections
using different power supplies resulting
from feeds from different substations, onconventional lines, the driver sets thehandle notch to off and back on again.
Since the driver of a high-speed
shinkansen could never do this, trackside
power supply auto-switching wasdeveloped to automatically switch power
supplies when passing between sections.
These technologies were developed aspart of the 1950 AC electrification tests
on the Senzan Line and subsequent
experience of full-scale commercial AC
operations on the Hokuriku main line
before being perfected as the shinkansenelectrification system.
Since the Tokaido Shinkansen runs
between Tokyo in the 50-Hz region andOsaka in the 60-Hz region and 60-Hz incarriage electrical equipment was
adopted to lighten weight, two frequency
conversion stations were built in the
50-Hz shinkansen operations region.
Conventional AC electrified lines use
20 kV because that was the voltage
supplied by the power companies at thattime but the shinkansen catenary isenergized at 25 kV.

Latest Shinkansen
Following the 1964 opening of theTokaido Shinkansen, transport demand
grew rapidly and the first 12-car train sets
were quickly increased to 16 cars with
about 10 services running every hour.

Japan Railway & Transport Review 42 • December 2005

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 running
8-pantograph train sets at a headway of
6 minutes caused a number of problems
due to wire vibration. At the time, theeasiest solution was to suppress wire
vibration by changing to a heavy
compound catenary design using thicker
wire at a higher mechanical tension.
Since this made the catenary structure
extremely complex in sections containing
a BT, there were more wire accidents,
resulting in the urgent need for an upgrade
solution. The solution was developmentof the AT feeding method instead of the
BT. The AT method was already in use at
11 kV and 25 Hz on the New Haven Linein Connecticut, USA, but had not beent e s t e d u s i n g c o m m e rc i a l p o w e r
frequencies. In the AT method, the feeder
line and contact wire are linked by asingle-winding transformer, and theneutral point is connected to the rail.
Since the substation feed voltage is twice
the overhead wire voltage, the interval
between 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 of
the AT method very attractive. Simulationof AT feeding circuits was started in 1964
and after proof-of-technology tests onsome narrow-gauge lines, it was adopted
commercially over the 259-km section
between Yatsushiro and Nishi Kagoshima(now Kagoshima Chuo) on the Kagoshima
main line in October 1970. Subsequently,
this method became the standard AC

Simple Catenary on Nagano Shinkansen(RTRI)

electrification technology in Japan where
it was adopted for both conventional andshinkansen lines—it also became thestandard method of AC electrification
overseas. Due to increases in demand
and aging infrastructure on the Tokaido
Shinkansen, the old BT feeding method
was replaced by reconstruction to the AT
method and as soon as all the old BT
sections were eliminated, operations
speeds were increased to 270 km/h fromthe original 210 km/h (Fig. 2).
In addition, although the thick, hightensile strength contact wire of thecompound catenary developed in Japan
continues in use, a new contact wire
design was adopted on the 117-km sectionof the Nagano Shinkansen between
Takasaki and Nagano opened in 1997, on
the 96-km extension of the Tohoku
Shinkansen between Morioka andHachinohe opened in 2002, and on the
137-km first southern section of the
Kyushu Shinkansen between ShinYatsushiro and Kagoshima Chuo openedin 2004. This new contact wire has acopper-clad steel core, providing a highwave propagation velocity and permitting
construction of a simple catenary structurewith high-tensile strength; R&D into newcatenary structures is still continuing.
The move to increased operations speeds
depends 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 been
constructed to standard gauge but toimprove access to the conventional linesof regional cities, tests were made on
operating shinkansen through services by
upgrading narrow-gauge lines to standard
gauge. This resulted in the recent openingof the 148-km Yamagata mini-shinkansen(1993) linking Shinjo with Fukushima
Station on the Tohoku Shinkansen, and the
127-km Akita mini-shinkansen (1997)
linking Akita with Morioka also on the
Tohoku Shinkansen.

Summary
Looking at the history of railway
electrification in Japan, most technology
in the Meiji period (1868–1912) was
imported and copied but then the trend
soon moved towards electric operations
using domestic technology. Private
railways took the lead over government
railways in introducing urban electric rail
services and during this period, electricity
for operations was supplied from therailway companies’ own generating
stations with surplus capacity sold totrackside housing and factories. However,
the railway companies’ electricity supply
business disappeared due to severe costcompetition with the larger power utilities
and because wartime government
regulations forced transfer of generation
capacity to the utilities. Electric rail
operations continued growing and theearly postwar period saw promotion of
main-line electrification by the newly
formed JNR due to severe postwar coalshortages hampering steam operations.
The major turning point came with SNCF’s
success in using commercial single-phase
AC power for rail operations while
Japanese electric railway companies werestill using DC electrification. On hearing
about SNCF’s success, JNR pushed ahead
with AC electrification of the Senzan Lineusing its own technical developments and,as a result of this experience, was able tointroduce AC electrification on the new
Tokaido Shinkansen when it opened in
1964.
In the early days, the BT feeding method
using trackside boosting transformers was
adopted but was subsequently replacedby the AT feeding method using low-costsingle-winding auto transformers, whichbecame the standard AC feeder system for
railways around the world, including
high-speed lines.
■

Further Reading
Railway Electrification Organization, History ofElectric 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).

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 fromTohoku University. He was manager of the Electrical Facilities Dept. at JR East and obtained adoctorate 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.

Japan Railway & Transport Review 42 • December 2005

69