Breakthrough in Japanese Railways 9

JRTR Speed-up Story 2

Part 2: Speeding-up Conventional Lines andShinkansen
Asahi Mochizuki
Reducing Journey Times on
Conventional Lines

is limited by factors such as curves, grades, and turnouts, so

Distribution of factors limiting speed

Many of the intercity railways in Japan are lines inscheduled speed can only be increased by focusing effort
on increasing speed at these locations.

The maximum speed of any line is determined by emergency

mountainous areas. So, objectives for increasing speeds

braking distance. However, train speeds are also restricted bycannot be achieved by simply raising the maximum speed.

various other factors, such as curves, grades, and turnouts.

Speed-up on curves

Acceleration and deceleration performance also impact
journey time. The impact of each element depends on the

The basic measures for increasing speeds on curves are

terrain of the line. The following graphs show the distributions

lowering the centre of gravity of rolling stock and canting theof these elements for the Joban Line, crossing relatively flat

track. However, these measures have already been appliedland, and for the eastern section of the Chuo Line, running

fully; cant cannot be increased on lines serving slow freight

through mountains.

trains with a high centre of gravity. Conversely, increasing

The graph for the Joban Line crossing the flat Kanto

passenger train speed through curves to just below the limit

Plain shows that it runs at the maximum speed of 120 km/h

where the trains could overturn causes reduced ride comfort(M part) for about half the journey time. Consequently, a

due to centrifugal force. The solution was to develop tilting or

10-km/h increase in maximum speed could reduce thependulum cars to absorb centrifugal force.

journey time by a few percent. The eastern section of the

Naturally, European operators considered such

Chuo Line running through mountains has almost no parts

measures, but building a safe and reliable tilting mechanism

operating at 120 km/h. Most operation is through speed-

proved difficult. One example of practical application inlimited curves and there are very few sections where theEurope was the UK’s Advanced Passenger Train (APT),

maximum speed can be increased.

but it was soon withdrawn from service. Italy also madepainstaking efforts to achieve stable control of tilting.

For lines like the eastern section of the Chuo Line, speed

Figure 1 Distribution of factors limiting speed for Joban and Chuo lines

Joban Line (Toride - Mito)

Chuo Line (Hachioji - Kobuchizawa)

Speed (km/h)

Speed (km/h)

120

120

αβ

100

100

80

80

60

M

C

40

60
40

S

20
0

P

Required time (%)

20

M
C

P
G

0

100

Required time (%)

T
S

αβ
100

M: Max. speed, C: Curve limit, P: Turnout limit, G: Grade limit, S: Signal limit, T: Tunnel, etc., limit α β: Acceleration/deceleration

51

Japan Railway & Transport Review No. 58 • Oct 2011

Test Series 591 Pendulum EMU

Test Series 391 Pendulum DMU(A Hundred Years of Progress in JNR Rolling Stock)

The first tilting systems in Japan used a pendulum system

could travel faster through curves. The Hakubi Line in west

where the body is tilted in curves by the centrifugal forces.

Japan was similarly electrified and served by Series 381

Such a tilting system inevitably suffers from tilt lag after

pendulum EMUs.

the train enters and exits the curve, but the body always tilts

Later, the engine output of DMUs was greatly increased,

reliably in the right direction.

offering similar speeds to EMUs on grades.

Although it was an incomplete solution, the policy in

In Japan, symmetric turnouts are widely used at stations

Japan was to start with this system and make steadyon single-track lines, causing severe speed restrictions for

improvements later. In Japan, this system is called natural

passing trains. To increase train speed, however, new track

pendulum (passive tilting).

layouts using simple turnouts have been introduced on

Series 591 electric multiple unit (EMU) test cars weresome lines, securing one straight track at each station forbuilt in 1970 for test runs on electrified lines across Japan.

passing trains.

In 1972, Series 391 diesel multiple unit (DMU) test cars were

Improvements to and spread of tilting trains

built and tested for non-electrified sections.
The first revenue service of a tilting train in Japan was in

When Series 381 pendulum EMUs were first introduced

1973 on the newly electrified section between Nagoya andbetween Nagoya and Nagano, they were operated by

Nagano using Series 381 limited express DC EMUs. Speeddrivers experienced in driving less powerful DMUs. As athrough curves was 15 to 20 km/h faster than the standard

result, these drivers tended to run the trains faster than the

speed, cutting journey times on that section by 16%.

scheduled speed through curves, causing heavy swing

However, the pendulum action on the Series 391 DMU

motion, giving the passengers (and crew) motion sickness,

was impeded by the transmission prop shaft, which, coupledand gaining a poor reputation.

with the attempts to improve ride comfort on pendulum

I also observed these problems of early tilting train

EMUs, delayed revenue service until 1989 when JR Shikoku

operations, as I rode with train drivers for a month when thestarted to run Series 2000 limited express DMUs.

Series 381 was first introduced.
Speeds were later reduced to an appropriate level,

Speed-up on grades and other sections

but the fundamental flaw of this system—tilt lag—was not

The many grades on trunk lines through mountains proved

overcome. The number of passengers may have increased,a serious impediment to speed increases. Climbing

but the train’s reputation remained poor.

grades at higher speeds requires more traction power andWhen the tilting system was later introduced on the Kisei

electrification is the easiest way to provide large amounts

Line, a method was developed to alleviate tilt lag by tiltingof power. Consequently, the previously mentioned section

the car before entering the curve. It involved pre-recording

between Nagoya and Nagano was electrified at the same

curve radii, transition curve lengths, and cant data for thetime as Series 381 pendulum EMUs were introduced. These

entire line in an onboard computer, and then tilting the car

powerful EMUs had a configuration of six powered cars andbody using actuators as the train approached the curve by

three trailer cars; they could climb grades at high speed,

calculating the tilt angle and angular velocity based on train

used electric braking when running down steep grades, andspeed. The method remains failsafe because the dominant

Japan Railway & Transport Review No. 58 • Oct 201152

Breakthrough in Japanese Railways 9

impetus to work to speed-up the shinkansen. Development

tilting force in the curve is still the natural pendulum.
This method was used successfully with pendulumof noise solutions and speed-increase technologies was

DMUs introduced to revenue service by JR Shikoku in 1989.

actively pursued, and the Tohoku and Joetsu shinkansen

The problem with DMU prop shafts impeding body tilt waslines reached a maximum speed of 240 km/h in 1985.

overcome by using two engines to cancel each other out.

Application of similar measures to the Tokaido

Such cars spread later to individual companies in the JR

Shinkansen allowed for a speed increase to 220 km/h ingroup with EMUs also using this controlled tilting.

1986, cutting the journey time between Tokyo and Osaka

The so-called tilting body system was also introduced toto less than 3 hours and between Tokyo and Hakata to lessthan 6 hours.

improve riding comfort by lowering the tilt centre as much as

The JR companies, established in 1987, had renewed

possible and minimizing lateral movement of the cabin floor.

enthusiasm for speed-up tests.

This simplified method does not use pendulum tilting;instead pressure differences between right and left air

A variety of test cars were built, successes were achieved

springs tilt the body. It is used widely on lines requiring small

in research on noise countermeasures, and environmental

tilt angles and is even used on some shinkansen cars.

standards were met at even 270 km/h in 1991. As a result,the Tokaido and San’yo shinkansen started running at a top

Shinkansen Speed-up and Background

speed of 270 km/h in 1992; JR West’s Series 500 could meet

As soon as the shinkansen started commercial operation

San’yo Shinkansen started running at 300 km/h in 1997.

environmental standards at up to 320 km/h in 1996, and thein 1964, development of the next generation started with a

A top speed of 320 km/h was now within reach throughgoal of increasing speeds to 250 km/h. The initial plan forsuch efforts, but many technical obstacles had to be

the first generation had been 250 km/h, but due to practical

overcome to reach this point. The next section explains thecircumstances, it was reduced to 200 km/h so the aim wasprogress in meeting these challenges.

to reach the original goal with the next generation.

Technical Issues and Solutions in
Shinkansen Speed-up

The type 951 test EMU was built in 1969 and achieved
a speed record of 286 km/h. The new technologies packed
in this test train included eddy-current rail braking that
became one of the factors that caused markedly increased

Environmental problems along lines—
noise countermeasures

wheel loads. So, type 961 test EMUs were built in 1973 to

Noise and vibration are the main environmental issues

overcome this problem.

alongside shinkansen lines and, with the sudden increase

enabled efficient braking from high speed. However, it

While the problem of excessive wheel load was solved,

in the number of shinkansen runs, trackside noise-pollution

the so-called 1970s oil shock and trackside environmental

in urban areas became a great public concern. As a result,problems (mainly running noise and vibration) became

the Environment Agency (now a ministry) established noise

key points of public discussion, making speed increase

standards in 1975; there were requests to reduce speeds todifficult for Japanese society to accept. As a consequence,meet these standards, which also served to hinder speed

the maximum operating speed of the San’yo Shinkansen

increases too. To meet one standard limiting noise to not

was restricted to 210 km/h when the line to Hakata wasmore than 75 dB, measures were implemented to block

completed; speed-up was not achieved.

noise along with basic R&D into identifying noise sources

Trackside noise and vibration had to be solved

and reducing noise generation. The sources of the noise

before operating speeds could be raised so shinkansen

were identified as rolling noise, current-collection noise, andengineers focused on them first. In that effort, the typeaerodynamic noise; the first countermeasures focused on

961 re-emerged for environmental countermeasures tests,

the main contributor—rolling noise created by unevenness

recording a maximum speed of 319 km/h in 1979. Basedof both wheels and rails.

on these tests for making environmental improvements, theWheel flats, a form of tread damage caused by sliding,Tohoku Shinkansen could meet the required environmental

were solved early on and grinding the head of rails proved

standards and started revenue service in 1982 at 210 km/h.

very effective.

However, the development of technologies to increase

Current-collection noise is composed of arc noise

speeds lacked driving force due to the social environment

caused by contact losses, pantograph aerodynamic noise,of the time.

and by sliding noise. Arc noise was the main contributor. The

In the midst of this situation, the French TVG high-speed

main cause is corrugation of contact wires but the cause of

trains started operation in 1981 at 260 km/h—faster than

this corrugation was not understood at the time, so covers

the shinkansen. The news shocked Japan and gave new

were added to pantographs around 1984 to block the noise

53

Japan Railway & Transport Review No. 58 • Oct 2011

The structure of pantographs was

Figure 2 Contribution of speed and noise source to noise level below 75 dB

also simplified and aerodynamic noise

Reverse L-shaped sound barrier, Number of pantographs halved, Bus line present

suppressed. The under-body area
was smoothed too, reducing noise
further. As a result, in 1996, the Series
500 EMUs reached 320 km /h withnoise held below 75 dB, and operation

Overall noise

started in 1997 at 300 km/h.
Meanwhile, the background noise

Rolling stock
aerodynamic noise

Noise
level
(dB)

of the wind tunnel used at that time forhigh-speed noise tests far exceeded

Structural noise

75 dB, so the Railway TechnicalResearch Institute (RTRI) newly built a

Rolling noisehuge low-noise wind tunnel in 1996.
The closed test section is 5-m

Current-collection noise

wide, 3-m high, and 20-m long, and
150

200
Speed (km/h)

250

300

can generate winds up to 300 km/h.
The open test section is 3-m wide,
2.5-m high, and 8-m long, and cangenerate winds up to 400 km/h thebackground noise is 75 dB(A) at the
maximum wind speed of 300 km/h.

instead. Concurrently, pantographs were connected by aThis wind tunnel has made great contributions to researchhigh-voltage bus to reduce arc noise when one pantographon aerodynamic noise countermeasures.

lost contact while others were still collecting current. This

Micropressure waves generated as a train runs throughmeasure allowed a reduction in the number of pantographs

a tunnel are another source of noise pollution, but additionalon each train. Aerodynamic noise of pantographs wasbuffering works at the tunnel portals as well as novel train

reduced by fitting covers over pantograph equipment. As

nose shapes have solved this problem.

a result, the Tohoku Shinkansen could meet the stricter
environmental noise standards at higher speeds andUnsprung mass—countermeasures to excessive wheel load

started operating at 240 km/h from 1985. Later research

The maximum static wheel load of the first Series 0

identified the cause of the corrugation, so arc noise wasshinkansen EMUs was 8 tonnes, and the maximum wheel

solved around 1990.

load during running at the service start was 11.7 tonnes.

In work to suppress ground vibration on the Tokaido

When type 951 test cars were fitted with eddy-current rail

Shinkansen, the results of tests to reduce axle load showed

brakes in 1969 to allow operation speeds of more thanthat efforts were needed to reduce car weight to an axle

250 km/h, a very high wheel load of about four times theload of around 10 tonnes and to reduce unsprung mass.

static wheel load was generated. The main cause was theSuch efforts were made, and the axle load and unsprungincrease in unsprung mass caused by the eddy-current

mass were successfully reduced.

rail brakes, but another important factor was the sudden

Noise countermeasures held noise below 75 dB. Along

increase in worn welded rail joints due to the increase in thewith movement countermeasure, it made it possible for thenumber of trains.

Series 300 EMU to operate at a top speed of 270 km/h.

In these circumstances, reduced unsprung mass was

The graph above shows how each noise sourcea key condition for speed increases. Type 961 EMUs with

contributed to total noise and the dependency on speed athollow-shaft drive systems had been built in 1973, but thethat time.

structure was complex and speed increases were not seen

It shows how body aerodynamic noise becomesas necessary at the time. As a result, there had been few

prominent as current collection noise decreases. Various

tests on increasing speed.

tests were run with different designs, but the effect could

As previously described, Japan was again looking at

not be measured clearly because aerodynamic noise wasincreasing shinkansen speeds in the 1980s but engineers

masked by other noise.

were pressed with solving both environmental problems andAfter 1990, smoothing the body surface and lowering

problems of unsprung mass. Complex structures like thethe height of the body cross-section proved effective.

Japan Railway & Transport Review No. 58 • Oct 2011

type 961 were deprecated by maintenance engineers, so

54

Breakthrough in Japanese Railways 9Type 951 test car eddy-current rail brakes of 1969

wheelsets, axle boxes, and gearboxes were lightened andhollow shafts were used to reach the target unsprung mass.
These measures were implemented from the Series 300
EMUs in 1990 to reduce both axle load and unsprung mass

Series 100 and 300 bogies both with 2500-mm wheelbase
(JR Central pamphlet)

by about 30% and allow speeds of 270 km/h to be reached.
Recent advances in rail welding technologies andperiodic grinding of the rail head have almost eliminatedrail unevenness, cutting fluctuations in wheel load. As aresult, the need for reduction in unsprung mass is not asstrong as before.

Weight reduction—suppression of kinetic energy
The a xle load of the Series 0 EMUs on the Tokaido
Shinkansen was less than 16 tonnes, but that of the Series
200 EMUs on the Tohoku Shinkansen was 17 tonnes due
to snow countermeasures, despite the aluminium-alloy
body. As described previously, weight reduction was the
key to increasing speed to the 270 km/h range. On the
Tokaido Shinkansen, vibration countermeasures wereachieved by reducing axle load to about 10 tonnes byusing aluminium-alloy car bodies and a drive system with
AC traction motor and regenerative brakes to slash theUnder-floor equipment with unified dimensions 

weight of electrical components.

(JNR pamphlet)

In fact, smaller axle load reduces the kinetic energy thatmust be absorbed by the mechanical brakes. The shinkansen
EMU design concept is to use electrical brakes constantly,

Clearly, aerodynamic resistance is an important factor

but they must be backed up by mechanical brakes evenfor increasing speeds, but train designs to minimize

when stopping from maximum speed. Thus, weight reduction

aerodynamic resistance were uncharted territory.

is essential to increasing speed. Consequently, in order toSeries 200 EMUs built for the Tohoku Shinkansen in 1981

achieve speed increases, the axle load was set to about 10

used a body mount structure. Aerodynamic comparison withtonnes even on other shinkansen lines that were built on a

the Series 0 showed that the resistance elements were trainsolider roadbed than the Tokaido.

cross-sectional area, pressure drag coefficient, length, andside friction coefficient. The contribution of each element to

The main measures to reduce weight were use of lightoverall resistance was quantified to some degree.

alloy bodies and regenerative braking, but use of compact
AC traction motors also made it possible to reduce the size

In 1985, the under-floor equipment of Series 100 EMUs

and weight of bogies. And as cabins hold a large number of

was unified to a fixed height and width to prevent snow

seats, aircraft seat manufacturing technology was used tobuildup. Spaces between equipment were blanked off tohelp reduce weight too.

make the under-floor area smooth. The idea was to achieve
the same effects as a body mount structure. While the body

Reducing running resistance at high speed

cross section and train length were the same as the Series

The main running resistance with high-speed trains is

0 EMUs, the Series 100 running resistance was significantly

aerodynamic resistance which increases very rapidly as the(about 20%) less.
Later measures, such as lowering body height, reducing

speed increases.

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Japan Railway & Transport Review No. 58 • Oct 2011

Figure 3 Train resistance (N) of high-speed trains

reground frequently.

250,000

lateral force in tight curves. One early

The cause of the problem was highSeries 0

solution was changing the tread profile

Series 100

from a cone to an arc. From around 1988,

200,000
Series 300
150,000

Series 500

research and tests were performed to findthe optimum value for the longitudinal andlateral rigidity of the axle box suspension.
A new Rolling Stock Test Plant wasestablished at RTRI in 1987 to test cars

100,000

under various conditions. Based on the
results, live tests were run on operating lines

50,000and then the designs went into practicalservice. Eventually, the RTRI test plant

0

0

50

100

150

200

250

300

could not meet demand and JR Central

350

built a rolling stock field test simulator andTrain Speed (km/h)

started tests in 2008. JR East also set up
high-speed bogie test equipment and is
working to improve running stability.

Figure 4 RTRI Rolling Stock Test Plant

The RTRI Rolling Stock Test Plant canhandle both shinkansen and conventionalline rolling stock at up to 500 km /h to

Test cardetermine when hunting occurs. In addition,
vertical and lateral movement, roll, yaw, andpitch trajectory conditions as well as actual
track irregularities can be applied to cars.
No. 4 axle
No. 3 axle

Such research, conducted on difficult
technologies, gradually delivered results
on achieving running stability and curve

Holding device
Vibrating device
Roller device
Flywheel device
Drive deviceNo. 2 axle
No. 1 axle

negotiation performance.
Self-propelled bed device

Fro m ab o u t 19 9 0, the rot atio nal
constraint between the bogie frame andcar body was changed from side bearing

Wheelbase converter(Railway Technical Research Institute)

slips to the lateral rigidity of air springs andyaw damper resistance, allowing selectionof appropriate rotational constraint.
The compatibility of stability and curve
negotiation performance was increased,

body cross-sectional area, and expanding smooth under-

preventing hunting at even higher speed ranges andfloor surfaces to the bogies further reduced runningenabling longer intervals between wheel grindings.

resistance to about half that of the Series 0, as shown inLong-wavelength track management (40 m versine)

figure 3 for 400-m trains.

was also conducted from about 1990 in conjunction with

The reduced running resistance led to great energy

speed increases to suppress rolling stock vibration caused

savings, but surprised designers of the Series 500 with its

by track irregularity.

much longer braking distances.

High-speed current collection—contact loss
countermeasures and low-noise pantographs

Achieving both high-speed running stability and curve
negotiation performance

The composite compound catenary equipment used at

The first Series 0 shinkansen did not suffer from hunting

the shinkansen start in 1964 was soon changed to heavy

even at speeds well in excess of the maximum operating

compound catenary as the number of trains increased.

speed, but wheels and rails on tight curves suffered from

Although contact wire corrugation occurred with this system,

increased wear and tear, and wheel tread profiles had to be

resulting in annoying noise caused by arcing at contact

Japan Railway & Transport Review No. 58 • Oct 201156

Breakthrough in Japanese Railways 9

losses, it was not a hindrance to current collection.

than 70% of the wave-propagation velocity, the wave-

To allow speed-up on the Tohoku Shinkansen, thepropagation velocity must be increased to increase the train

catenary hanger interval was shortened to match the vibration-

maximum speed. In simple terms, this means increasing

followup characteristics of pantographs. Also, springs werethe contact wire tension and decreasing its mass. Such

added between the collector head and the slider.

measures were practically difficult using the conventional

Although no significant improvement was seen fromcopper-alloy wire, so a new wire was developed in 1986. It

these measures, the maximum speed was raised at this time

had an aluminum-covered steel core wire, but was changed

from 210 km/h to 240 km/h by fitting covers over pantographagain in 1991 to copper-covered steel core wire to facilitate

equipment, reducing the number of pantographs, andeasy replacement.

running a high-voltage bus between pantographs.

Entering the 2000s, newly introduced copper-covered

The changes caused heavy wear of sliders, which weresteel core contact wires had a cross sectional area ofwidened as a stopgap measure. Unexpectedly, this measure

110 mm 2, a tension of 19.6 kN, and a wave propagation

eliminated the corrugation and subsequent analysis by RTRI

velocity that had been increased from the 355 km/h ofidentified the exact cause of contact wire corrugation, thus

conventional copper-alloy wire to 519 km/h. It guaranteed

finally solving the problem.

stable current collection at up to 360 km/h. Moreover, theThe RTRI conducted research on overhead catenary

simple catenary structure resulted in huge cost reductions

systems in the 1980s ahead of further speed-ups andfor overhead line equipment. Existing overhead contact lines

developed high-speed current collection theories based

also were replaceable, but tension is increased if left as-is.

on the wave-propagation velocity. Because there is very

Meanwhile, operators in the JR group are designing

little contact loss when the train maximum speed is lesssimpler pantographs to reduce aerodynamic noise. The

Figure 5 Cross sections of test contact wires
Hard drawn copper contact wire
(170 mm2)
15.49

Steel

CopperCS contact wire (170 mm2)
15.35

10.1

Kyushu Shinkansen new overhead contact wire equipment

(Author)Kyushu Shinkansen pantograph (Author)

Steel
Aluminium

TA contact wire (150 mm2)

7
15

17
10

14

57

Japan Railway & Transport Review No. 58 • Oct 2011

pantograph developed by JR East in 2002 is the simplest

was very stable, so it remained basically unchanged.

and does not even need a pantograph cover. The above

The Series 200 EMUs on the Tohoku and Joetsu

photograph is an example of a pantograph for Series 800

shinkansen (1980) used propulsion technologies fromrolling stock for Kyushu Shinkansen in 2004.

the types 951 and 961 with thyristor phase control for
acceleration and resistance control with chopper devices

Today, most shinkansen have t wo pantographs

for braking. This helped improve adhesion performance inconnected by a high-voltage cable.

snow. Series 100 EMUs in 1985 also used phase control by

Propulsion systems

thyristor for power running, and eddy-current disc brakes

The first shinkansen EMUs received 25-kV, 60-Hz single-

were developed for trailers. Introduction of trailers cut bothphase AC power, which was stepped down by transformers

costs and weight.

and rectified by silicon diode bridges to provide power

A four-quadrant converter, variable voltage variable

for DC motors. The DC motors were converted into power

frequency (VVVF) inverter AC induction motor system, which

generators when the dynamic braking system was working,had been developed from 1985 for the Hokuriku Shinkansen

and brake energy was dissipated as heat by resistors.

with its long steep grades was nearing completion byType 951 test cars (1969) used choppers for brakes,

the end of the JNR era. However, the construction of thewhile type 961 test cars (1973) used phase control by

Hokuriku Shinkansen fell behind schedule, so the technology

thyristor bridges. However, the Series 0 EMU power system

saw first practical use on JR Central’s Series 300 EMUs
(1990). All shinkansen EMUs introduced after the Series 300
adopted this system. These new EMUs had regenerative
brakes, which, together with smaller and lighter electricalequipment, offered great weight reductions, making major
contributions to speed increases. The power factor could
also be controlled, assuring highly effective utilization ofcollected power, and curbing increases in collected current
required for higher speeds.
Initially GTO thyristors were used for the four-quadrant
converter and VVVF inverters but have been replaced byinsulated gate bipolar transistors (IGBT) to greatly suppress
inductive obstruction current and other problems. Socalled vector control is also used due to its high adhesion
properties and to suppress increases in braking distancecaused by higher speeds. Braking distances are also cut by
injection of ceramic particles on rails to increases adhesion.

Energy disposal of high-speed braking
Eddy-current disc brake (JNR pamphlet)

Figure 7 Series 300 shinkansen propulsion system

DC
VVVF

4QC

4QC

Transformer

4QC

4QC

VVVF
Inverter

Capacitor

Four-quadrant converter
M

M

M

M

M

Three-phase induction motor

Japan Railway & Transport Review No. 58 • Oct 2011

M

M

M

Three-phase induction motor

58

Breakthrough in Japanese Railways 9

Braking from high speeds requires disposal of huge

Clad metal discs of bonded cast steel and cast iron wereamounts of kinetic energy. Dissipating such high energy withused for a time but were changed to forged steel to handle

mechanical brakes alone is impractical, if not impossible,

increasing speeds.
Forged steel discs deform with frictional heating and the

because it requires frequent and intense maintenance works

engineers struggled to overcome this problem. Fortunately,

and results in shorter service life.
To overcome this problem, motors are thus installed onas mentioned, the great reductions in rolling stock weight

all axles, and are braked using dynamic braking to dissipate

suppressed the amount of brake energy to be dissipatedenergy as heat. If this electrical braking fails, the mechanicaland improved the problem to some extent.
Automatic train control (ATC) started with a stepped

brakes function as a backup.
To handle the high frictional heat generated bybraking curve, but there was some surplus in braking

mechanical braking from top speeds with maximum

distance set for each step. To raise maximum speed without

deceleration, the wheel-mounted brake discs are madeincreasing headway, this was changed to a non-stepof nickel-chromium-molybdenum low-alloy cast iron withdeceleration curve with new ATC technology from 2002.

sintered metal brake pads.

Developments in airtight body design and window glass

The mechanical brakes are controlled by electromagnetic
straight air brake equipment, and the foundation brake

Air pressure around a train changes greatly as it passes

rigging uses hydraulic control, offering compact size withthrough a tunnel.
The solution is to build airtight bodies, thereby eliminating

low weight and high responsiveness.
For braking force, non-adhesive brakes were avoided

pressure changes. The bodies were constructed fromand only adhesive force was used. However, there was morealuminum alloy to decrease weight to facilitate higher speeds.

sliding than expected and the added precautionary slide

Train bodies were made perfectly airtight, but cabin pressure

detection and re-adhesion system was insufficient. Tests onrose gradually during running, which caused problems, so

the type 951 for next-generation test rolling stock were madevalves were added to release pressure build up.
As air pressure fluctuations caused when passing

by fitting non-adhesive eddy-current rail brakes, but failed

through a tunnel increased as trains were made to run faster,

due to undesirable effects on rails.
However, chopper control proved successful incars were made with small windows to reduce the impact onmatching speed characteristics of braking force to that ofbody shell strength, although passengers seated in two rows

adhesion coefficient.

prefer larger windows for better panoramic views. Reinforced
glass was used, and new unbreakable polycarbonates were

To increase adhesion, an abrasive block was initiallyadopted in some later series shinkansen.

used to polish wheel treads, but in the 1990s, injection ofceramic particles was added as an additional measure.

Increased speed through curves

From around 1995, the service braking force of the front
cars in the direction of travel was reduced or eliminated,

The minimum radius of curves on the Tokaido Shinkansen

eliminating sliding and allowing for a shorter braking distance

was to 2500 m. When the maximum operating speed wasof the train as a whole.

changed to 270 km/h, the maximum cant on curves was

Induction motor vector control was added from theincreased from 180 mm to the standard maximum of 200 mm.

late 1990s and improvements in adhesion technologies

Steady lateral acceleration was set at 0.09 G to giveo f fe re d i m p rove d d e c e l e rat i o n s u p p o r t i n g s p e e dsome leeway for acceleration, and maximum cant deficiency

increases to 300 km/h.

was increased from 90 to 110 mm. These changes allowedWith the introduction of trailers, eddy-current disc brakes

Series 300 shinkansen to pass 2500-m curves at speeds

were developed due to the need for electrical braking.

of 255 km/h and 3000-m curves at 270 km/h. However,

Dynamic braking changed to regenerative braking, andthere are still many sections with speed limits of less thanwith the improved re-adhesion performance of AC induction

270 km/h and the only method for cutting journey times

motors (adoption of vector control, etc.), the braking

further by running through 2500-m curves at 270 km/h was

equipment for trailers became unnecessary as sufficient

to introduce tilting body.
JR Central set up a Vehicle Dynamic Simulator at its

braking forces were provided from motor cars.

research facility in 2003.

Brake commands were sent initially using the electro-

The simulator moves a ride comfort test platform topneumatic straight air brake method but switched to electric

generate centrifugal forces and assess ride comfort.

commands from Series 200 EMUs in 1981.

Therefore, it is a huge system.

The early brake disks had a shorter service life, because

Eventually, the Series N700 was fitted with an air-spring-its ability to handle the frictional heating loads at top speeds

driven system, tilting the body by about 1º in a 2500-m

of 210 km/h was lower than expected.

59Japan Railway & Transport Review No. 58 • Oct 2011

curve. The system helps reduce centrifugal force felt byuncharted territory in terms of technology. However, ourpassengers and permits trains to run through 2500-m curves

predecessors faced the challenge dauntlessly andat 270 km/h.

succeeded in their efforts.
EMU and AC electrification technologies were still in

Conclusions

their infancy in 1941, and there were no semiconductors or

The origins of Japan’s shinkansen high-speed railway are

1960s was good timing.

computers. So, from the technical viewpoint, starting in the
Although it may be discourteous, with hindsight,

relatively old, dating back to the ‘bullet train’ plan, which

the first shinkansen engineers had good luck and skill instarted construction in 1941.
Half a century has passed since design for the current

equal measures. Difficulties arose in quick succession

system started in earnest in 1958. At the time, there wereonce shinkansen operations started, and social pressures

no railways operating faster than 200 km/h, and this was

slowed the momentum of speed increases. These issues
were overcome by diligent research, and things that wereconsidered ideal targets at first were achieved eventually.
Shinkansen development was truly an amazing process.
Today, environmental standards have already been met

Table 1 Maximum speed chronology
Date

Shinkansen Line/Rolling Stockfor speeds up to 320 km/h, so operation at that speed will be

1 Oct 1964

Start of Tokaido Shinkansen

Nov 1965

Operation between Tokyo and Osaka in 3 h 10 min.

speeds further under Japan’s current environmental

210 km/h

1972

Type 951 Shinkansen test car

286 km/h

15 Mar 1972

Start of San’yo Shinkansen to
Okayama

210 km/h

10 Mar 1975 Start of San’yo Shinkansen to Hakata

210 km/h

7 Dec 1979

319 km/h

Type 961 Shinkansen test car

achieved. However, it will be difficult to increase shinkansen

Max. Speed

regulations so magnetic levitation high-speed railways are
the future hope. Concrete plans are already being madeand the chances of achieving revenue services at maximum
speeds in the 500 km/h range still seem good.
This article contains a lot of technical information, andI hope that you were able to digest it. I thank you for taking
the time to read it.

27 Sep 1981 Start of French TGV South-East Line at 260 km/h
23 Jun 1982

Start of Tohoku Shinkansen to Omiya

210 km/h

14 Mar 1985 Start of Tohoku Shinkansen to Ueno

240 km/h

Sep 1985

Series 100 test

260 km/h

1 Nov 1986

Series 100 operating on Tokaido andSan’yo shinkansen

220 km/h

Mar 1989 Series 100N on San’yo Shinkansen

230 km/hJoetsu Shinkansen in operation(in tunnel)

275 km/h

28 Feb 1991

Series 300 test

325.7 km/h

14 Mar 1992

Series 300 operating on Tokaido andSan’yo shinkansen

270 km/h

8 Aug 1992

JR West WIN350 test car

350.4 km/h

20 Dec 1993

JR East STAR21 test car

425 km/h

21 Jul 1996

JR Central 300X test car

443 km/h

22 Mar 1997

Series 500 operating on San’yo
Shinkansen

300 km/h

5 Mar 2011

Series E5 operating on Tohoku
Shinkansen

300 km/h

Mar 1990

Japan Railway & Transport Review No. 58 • Oct 2011

Asahi Mochizuki
Mr Mochizuki is a Consultant at Japan Railway Rolling Stock &Machinery Association. He joined JNR in 1960, where he was involved
in rolling stock maintenance, and designing EMUs, shinkansen, andelectric rolling stock. Subsequently, he served as a Chief Engineer
in the Transportation System Division at Toshiba Corporation prior toassuming his current position.

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