Kenji Sato
Central Japan Railway Company
Advancements in Energy Savings for
Tokaido Shinkansen Rolling Stock
ADVANCEMENTS in ENERGY SAVINGS for TOKAIDO SHINKANSEN
ROLLING STOCK
Kenji Sato
Dr. Eng., Consulting and Coordination Office - Overseas High Speed Railway Project
Technical Planning Department, General Technology Division, Central Japan Railway Company
1. SUMMARY
The Tokaido Shinkansen, Japan’s first High Speed Rail, has maintained an unparalleled record
in safety, punctuality, mass transport capacity and energy savings. In particular, its energy
saving performance is such that even though its maximum operational speed has been raised,
energy consumption has been decreased through the introduction of new series Shinkansen
rolling stock. This can be attributed to two fundamental concepts at the heart of the
Shinkansen’s design: the crash avoidance concept, which employs dedicated, passenger-only
tracks and a fail-safe, reliable signalling system to eliminate the potential for collisions with road
vehicles or other trains, and the Electric Multiple Unit concept, using distributed power systems
on rolling stock. Combined with advanced power electronics technology, these fundamental
design concepts provide the flexibility which has helped to continuously improve Shinkansen
rolling stock to be ever more energy-efficient by featuring a lightweight body, less running
resistance and more efficient performance using regenerative braking. Applying these concepts
and technology, JR Central has continued to reduce the energy consumption of the Tokaido
Shinkansen by introducing the new series of higher performing, more energy-efficient
Shinkansen rolling stock, culminating in energy consumption in 2011 being 30% less than
results from 1990.
2. INTRODUCTION
Next year the Tokaido Shinkansen will
celebrate its 50th anniversary. When it
commenced commercial operation in 1964,
the Tokaido Shinkansen was the first railway
in the world to operate at speeds of over
200km/h, and since then it has served over 5
billion people. The Tokaido Shinkansen is
unparalleled in terms of safety and
punctuality, with no train accidents resulting
in fatalities since the commencement of
operation. The annual average delay per
train, including train delays caused by natural
disasters such as typhoons and earthquakes,
is less than one minute. Furthermore, even
though its maximum operational speed has
been raised, energy consumption has been
decreased through the introduction of new
series Shinkansen rolling stock.
These defining characteristics of the Tokaido
Shinkansen are ensured by two fundamental
design principles, the Crash Avoidance
Concept (CA Concept) and the electric
multiple unit (EMU) system of rolling stock. In
conjunction with the introduction of power
electronics
technology,
the
Tokaido
Shinkansen rolling stock is designed to
reduce train set weight and effectively utilize
regenerative braking.
This paper firstly presents the crash
avoidance concept and the distributed
traction
system.
Following
this,
the
development of traction circuit systems is
introduced as an example of efforts to
achieve
advanced
energy-saving
performance. Finally, this paper illustrates
how the Shinkansen has evolved into a fast,
highly efficient rail system featuring both
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Kenji Sato
Central Japan Railway Company
Advancements in Energy Savings for
Tokaido Shinkansen Rolling Stock
large carrying capacity and low energy
consumption.
that collisions with any road vehicles can be
completely eliminated.
3. NOTATION
4.1.2
EMU: Electrical Multiple Unit
ATC: Automatic Train Control system
CA Concept: Crash Avoidance Concept
The second element is the Automatic Train
Control system, or ATC, which is highly
reliable and proven failsafe. The functions of
the ATC as shown in Fig. 1 are;.
4. TOKAIDO SHINKANSEN ROLLING
STOCK BASIC CONCEPTS
• The ATC is a digital-type signalling
system
preventing
train-on-train
collisions and excessive speeds.
• The ATC system consists of the ATC
Ground Facility and the Onboard ATC
equipment. Through the track circuits,
the ATC Ground Facility transmits digital
signal information regarding the number
of clear block sections (the location of a
preceding train), a path code and a track
circuit ID. Receiving this information, the
Onboard ATC equipment calculates a
braking curve and activates braking so
as to follow the braking curve.
The Tokaido Shinkansen is built based on
the core concept of “Crash Avoidance.”
Alongside this concept, the Tokaido
Shinkansen rolling stock employs the
“Distributed Traction System”, used on
EMU train sets. These basic concepts set
the Tokaido Shinkansen rolling stock apart in
terms of its large transport capacity, high
efficiency, and energy savings.
4.1 CRASH AVOIDANCE CONCEPT
The Crash Avoidance Concept (CA Concept)
is comprised of two elements.
1) The use of dedicated tracks exclusively
for high-speed passenger rail service
2) A fail-safe, reliable, proven Automatic
Train Control (ATC) system.
Automatic Train Control (ATC)
The ATC system has prevented train-on-train
collisions for 48 years and contributes to the
Shinkansen’s safe high-speed and highfrequency operations.
On-board
equipment
ATC Brake Command
Position
4.1.1 Dedicated Track for
passenger rail service
high-speed
Data of Rolling Stock
Performance
Track Circuit (Rail)
The first element of the Crash Avoidance
Concept is dedicated tracks. Dedicated track
means that no trains other than high-speed
passenger trains, such as freight trains or
conventional trains, are used on the same
track. By separating heavy freight trains that
have poor braking performance and
conventional trains that have inferior running
performance from HSR, the risk of collision is
completely eliminated.
Another important characteristic of these
dedicated tracks is that they are completely
level crossing free. No level crossings mean
Speed
Braking Curve
ATC Signal
Alignment Data
(Number of Clear Block Section, Track Circuit ID, Path Code)
Ground
Facility
Fig. 1. Block Diagram of ATC System.
4.2 Advantages of the CRASH AVOIDANCE
CONCEPT
The concept of crash avoidance not only
ensures the all-important need for safety on
high-speed railways, but also contributes
greatly towards the efficient operation of
high-speed rail.
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Kenji Sato
Central Japan Railway Company
Advancements in Energy Savings for
Tokaido Shinkansen Rolling Stock
As a result, rolling stock can be made lighter
as the need to focus on crashworthiness is
eliminated. The system is also not restricted
by old standards that require interoperability
with conventional lines. This allows for a
larger cross section of rolling stock, which in
turn enables the larger passenger capacity.
4.3 Distributed Traction System
In general, the traction systems of highspeed trains can be categorized into two
types in terms of power distribution: the
distributed
traction
system
and
the
concentrated traction system.
Figure 2 shows the example of those
systems. The distributed traction system is
represented by the electric multiple unit
(EMU) system, in which a train set has many
power cars and in some cases, one or more
trailers. Conversely, the concentrated traction
system is represented by the locomotive
system, in which a train set has one or more
locomotives to pull or push the trailers.
14 Motor Cars
2 Trailers
Distributed Traction System
the ratio of motor cars increases, the ratio
of regenerative braking also increases to
maximise energy savings.
2) Higher acceleration and deceleration
performance resulting from greater total
load on powered axles: The acceleration
and deceleration performances are
affected by the adhesion between wheels
and rails. Since the distributed traction
system has more powered axles and a
higher total load on powered axles than
the concentrated traction system, it is
possible to set lower acceleration or
deceleration forces per axle while still
obtaining a higher traction performance
overall.
3) Effective use of space above the floor for
passenger cabins: While passenger
cabins are rarely deployed on locomotives
for the concentrated traction system, with
the distributed traction system the space
above the floor can be fully utilized as
passenger
cabins
to
yield
more
passenger capacity owing to its electrical
equipment being mounted under the floor.
An Electrical Unit
①
②
③
④
⑤
⑥
⑦
⑧
⑨
⑩
⑪
⑫
⑬
⑭
⑮
⑯
:Passenger car
:Powered axle
MM
CI : Power Converter
MTr : Traction Transformer
MM: Traction Motor
Concentrated Traction System
①
② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨
⑩
2 Locomotives
8 Trailers
MM
Fig. 2. Example of Distributed Traction
System and Concentrated Traction System.
4.4 Superiority of the Distributed Traction
System
The features of the distributed traction
system are:
1) Effective use of regenerative braking: As
4) Reduction in maximum axle load: Lower
maximum axle load with averaged load
distribution can optimize the lifespan of
infrastructure and reduce construction
costs.
5. ENERGY CONSERVATION DUE TO
TECHNOLOGICAL INNOVATION
Technological innovation to improve rolling
stock performance leads to further energy
conservation. Major elements for reducing
energy consumption are:
1) Reduction in running resistance
2) Increase in the number of cars with
regenerative braking
3) Further weight reduction
The First element to address is the reduction
in running resistance. When the train is
running at high speeds of over 200km/h, the
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Kenji Sato
Central Japan Railway Company
train has to counteract the aerodynamic
resistance. Reducing aerodynamic resistance
promotes energy savings.
Second is increasing the number of motor
cars and more effective use of the
regenerative brake system.
Third, further weight reduction promotes
energy conservation. The lighter the weight
of the train set, the less energy required to
accelerate and maintain the speed of the
train.
5.1 Improvement of Rolling Stock
Performance
To enhance passenger service and
strengthen competitiveness against other
transportation modes, such as airlines, JR
Central is steadily promoting measures to
increase train speed, reduce travel time and
boost transport capacity. JR Central raised
the maximum train speed (which was
220km/h with the Series 0 and the Series
100) to 270km/h with the Series 300. The
maximum speed of the Series N700 in the
Tokaido Shinkansen is 270km/h, however,
the speed on curves with a radius of 2,500m
has been raised from 250km/h to 270km/h
owing to the newly-equipped body inclining
system. In the Sanyo Shinkansen, the
maximum speed is 285km/h with the Series
700 and 300km/h with the Series N700 as
shown in Fig 3.
Advancements in Energy Savings for
Tokaido Shinkansen Rolling Stock
5.2 Downsizing and Weight Reduction of
Traction System
The Shinkansen EMUs take advantage of
innovations in power electronics technology
and have developed with the advancement of
power devices. The Series 100 used DC
traction motors and rheostatic braking and as
a result required heavy resistors to dissipate
the braking energy.
In 1990, the Series 300 used GTO thyristor
control to achieve an AC drive system, and in
1997 the Series 700 became the first highspeed train in the world to use the innovative
IGBT technology. This system enables stable
AC regenerative braking, dispenses with the
need for braking resistors, and achieves
considerable weight reduction [1].
Moreover, the conversion system of the
Series N700 employed the innovative and
lightweight “Power Converter with Train Draft
Cooling System” technology, as shown in Fig.
4. Train-draft-cooling power converters are
advantageous in that they are lighter in
weight since cooling blower motors, fans and
liquid cooling mediums are not required.
Figure 5 shows trends in the weight-power
ratio of the traction systems of Shinkansen
trains, from the Series 0 to the Series N700.
The systematic change of the traction system
has contributed to achieving powerful,
lightweight, and efficient traction systems for
high-speed EMUs.
PWM Power Convertｅr
Airflows (Train-Draft)
Aluminum Fin
Inverter
インバータ
Aluminum Fin
コンバータ
Converter
Airflows (Train-Draft)
Fig. 3. Transition of the Tokaido Shinkansen
Rolling Stock.
Fig. 4. Trends of Weight of Traction System
per Power in a Trainset (as Series 0: 100).
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Central Japan Railway Company
Advancements in Energy Savings for
Tokaido Shinkansen Rolling Stock
(as Series 0:100)
Weight of traction system/Power in a train-set
100
80
60
40
20
0
Series 0
Series 100
Series 300
Series 700
Series N700
1st-generation Rolling Stock
2nd-generation Rolling Stock
Traction
system
DC motor driven
AC asynchronous motor driven
Brake
System
Rheostatic Brake System
Regenerative Brake System
the catenary. In the Series N700, the number
of motor cars is increased to 14, and, in
addition, the output power of each motor car
is also increased. As a result, 14 motor cars
can provide the braking effort for the 16 cars
of the train, as shown in Fig. 7. In this way,
the Series N700 increases regenerative
energy by approximately 10-20%, compared
with the Series 700.
《Series 700》
Fig. 5. Trends of Weight of Traction System
per Power in a Trainset (as Series 0: 100).
T
M
Catenary
M
M
T
T
M
M
M
T
Regenerates braking energy of 12 cars
5.3 Reducing Running Resistance
No regeneration in 4 trailers
《Series N700》
Tokaido Shinkansen trains run though
densely populated areas at high speed. The
wayside noise caused by aerodynamic
performance is one of the most significant
ongoing issues. Shinkansen Rolling Stock
has been streamlined to reduce aerodynamic
noise. The consecutive improvements of
aerodynamic performance in each series of
rolling stock have continually reduced
running resistance. Figure 6 shows the
running
resistance
of
each
series.
Comparing Series 0 and Series N700 at
220km/h, Series N700’s running resistance is
half that of the Series 0.
Series 0
Catenary
T
M
M
M
M
M
M
M
M
T
Regenerates braking energy of all 16 cars
14 motored cars provide braking for the 2 trailers
Fig. 7. Effective Use of Regenerative Brakes
5.5 Energy Saving due to introducing
Energy-efficient Rolling Stock
The energy consumption depends primarily
on the running resistance, the weight of a
train set, the efficiency of electrical
equipment
and
the
performance
of
regenerative brakes.
Running Resistance
Series 700
Series 100
Series N700
0
50
100
150
200 220
250
300
Speed [km/h]
Fig. 6. Running Resistance of each Series of
Shinkansen Rolling Stock
5.4 Effective Use of Regenerative Braking
Increasing the number of motor cars can also
enhance the effective use of regenerative
braking. The Series 700 has 12 motor cars
out of 16 total cars, and the braking kinetic
energy can be regenerated and returned to
Figure 8 shows the comparison of energy
consumption
by
different
series
of
Shinkansen high-speed trains. The Series
N700 consumes the energy equivalent to
approximately half that consumed by the
Series 0 in running at 220km/h between
Tokyo and Shin-Osaka. Shinkansen rolling
stock has continually evolved to become
more energy-efficient. Figure 9 shows the
relationship between energy consumption
and the ratio of energy efficient rolling stock.
The area on the left hand side of the graph
represents first generation rolling stock,
which doesn’t feature a regenerative braking
system. The middle area represents second
generation rolling stock, equipped with
regenerative braking systems and an energy
efficient design. It can be found that as the
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Kenji Sato
Central Japan Railway Company
Advancements in Energy Savings for
Tokaido Shinkansen Rolling Stock
ratio of energy-efficient rolling stock
increases, the unit energy consumption
decreases correspondingly. After the Series
100 was retired and the first generation
rolling stock ceased running in 2003, energy
consumption increased slightly. This was due
to the operation time table being reviewed
and the average operation speed being lifted.
Then, after the more energy-efficient Series
N700 rolling stock commenced service in
2007, the energy consumption began to
decrease again, bringing the energy
consumption of 2011 down to only 70% of
1990’s figures.
The history of the
Shinkansen rolling stock is proof of how
energy-efficient rolling stock promotes energy
savings.
1st-generation Rolling Stock
2nd-generation Rolling Stock
220km/h
270km/h
100%
91%
79%
84%
73%
66%
68%
51%
Series 0
Series 100
Series 300
Series 700
Series N700
*Comparison of Electric Power Consumption between Tokyo and Osaka.
Fig. 8. Comparison of Energy Consumption
of Shinkansen Trains (as Series 0: 100).
6. CONCLUSION
The Tokaido Shinkansen’s energy saving
performance is outstanding in that even
though its maximum operational speed has
increased,
energy
consumption
has
decreased through the introduction of new
series Shinkansen rolling stock. This defining
achievement is built on two fundamental
concepts at the heart of the Shinkansen’s
design: the crash avoidance concept and the
Electric Multiple Unit concept, using
distributed power systems on rolling stock.
Using the crash avoidance concept, rolling
stock can be made lighter weight and
achieve a larger cross section of the car body.
The distributed traction system combined
with advanced power electronics technology
makes the rolling stock ever more energyefficient by featuring a lightweight body, less
running resistance and more efficient
performance using regenerative braking.
With these advantages derived from these
basic concepts, JR Central has developed
and introduced not only higher operational
speeds, but also low energy consuming
rolling stock.
As a result, the Series N700 consumes
energy equivalent to approximately half that
consumed by the Series 0, the firstgeneration Shinkansen train, in running at
220km/h between Tokyo and Shin-Osaka.
This leads to the unit energy consumption in
2011 being 30% less than results from 1990
by introducing the new series of higher
performing,
more
energy-efficient
Shinkansen rolling stock.
REFERENCES
Fig. 9. Changes in Ratio of Tokaido
Shinkansen Energy-efficient Rolling Stock
and Unit Energy Consumption
[1] Y. Hagiwara, S. Ishikawa, M. Furuya,
“Innovative Lightweight Technologies
Using Power Electronics on Shinkansen
High-Speed Electric Multiple Units,”
Transportation Research Record, Journal
of the Transportation Research Board,
No.1995, pp. 43-51, 2007.
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