Add us to your taskbar by dragging this icon RGI logo to the bottom of your screen.


Advanced Commuter Train pioneers changes on Tokyo's suburban network

01 Apr 2002

INTRO: Testing of East Japan Railway's prototype Advanced Commuter Train is now in hand. Breaking with several conventions, the articulated EMU makes extensive use of on-board information technology to reduce operating costs and increase reliability

BYLINE: Takashi Endo

Director, Advanced Railway System Development CentreEast Japan Railway Co

JR EAST operates 17 suburban routes in the greater Tokyo area, moving 14 million passengers every day. Pressure to increase capacity and reduce operating costs is growing, and it is vital that JR East is well prepared to cope with future demand.

Significant strides have already been made in cutting costs and improving performance thanks to a programme to replace JR East's suburban EMU fleet. The most significant change was the introduction of the Series 209 EMU in 1993 (RG 4.93 p219), when the concept of suburban trains with a life of 30 to 40 years was replaced by the idea of a train with a 13-year life during which no major overhaul is needed.

Light weight, low energy consumption and reduced maintenance costs led to Series 209 being described as the 'half-life, half-weight and half-price train'. Further refinements followed with the development in 1998 of Series E231, initially known as Series 209-950. As a result of this policy, over 50% of JR East's 8000 commuter cars have been built within the past 10 years.

Despite these impressive achievements, further progress must be made, and the Advanced Commuter Train has been developed to form the next generation of suburban stock for Tokyo commuters.

Our goals in developing the ACT were to design a modern train offering passengers more space, comfort and accessibility, at the same time increasing reliability, cutting life-cycle costs and ensuring that operation is environmentally sound.

Improvements to reliability will allow rapid recovery from any operating problems, and a more reliable service will also contribute to an overall increase in safety levels. Life-cycle costs are being reduced through changes in bodyshell construction, and the use of direct-drive synchronous motors with autonomous and decentralised power control will bring energy savings and other improvements.

Move to fixed formations

Most Japanese commuter coaches are conventional 20m bogie vehicles, allowing trains to be easily reformed when necessary. However, fixed-formation trainsets are increasingly being used in Japan, and for ACT we decided to move to a fixed formation with articulated cars, even though this has major implications for maintenance facilities.

Articulation on the five-car ACT offers an accessible, barrier-free interior throughout the set. By shortening the intermediate cars to 13400mm, the internal body width can be increased from 2750mm to 2830mm within the existing loading gauge, increasing the space available for passengers (Fig 1).

Two designs of articulated bogie have been developed, one where the body is supported by two air springs and another with four air springs.

The ACT makes use of the latest bodyshell construction methods. Three of the cars use stainless steel, and two are aluminium. On two of the cars, stainless steel double-skin panels are used to form the bodyshells. In this process the panels are made from a honeycomb structure laser welded between two stainless steel sheets. Compared to previous designs, this requires fewer materials and simplifies assembly.

The exterior can be left unpainted, and the inner side of the double-skin panels used for interior finishing.

One intermediate car has a stainless steel single skin, and the two other vehicles make use of a double-skin aluminium design that has been adopted for recent shinkansen and some limited express trains.

All cars are air-conditioned, using packs mounted on the roof of three cars per set.

The traction equipment on many recent Japanese commuter trains includes three-phase induction motors driving through cardan shafts. For the ACT we have developed a direct drive permanent magnet synchronous motor, with the rotor directly fixed to the axle. The motor can be fitted as a sealed unit, allowing maintenance intervals to be increased and reducing noise levels by 15dB within a 1m radius compared with the traction motors on a Series E231 trainset. The arrangement also reduces power consumption by 5%.

Fully integrated power control systems can offer low costs, but a failure is likely to have quite serious effects. Despite the cost advantage of central control, we have decided to move on the ACT to a decentralised control structure for the traction equipment. Thus a single variable-voltage, variable-frequency inverter was previously used to control four traction motors, but on the ACT each motor has its own VVVF inverter (Fig 2). This reduces the train's dependence on critical components and improves reliability.


The train is equipped with a radio transmission unit, server and 10Mbps Local Area Network (Fig 3). Ethernet was chosen for the data network, as it is cheaper than developing a custom protocol, and its use eliminates about 60% of the wires needed in a traditional vehicle. The ethernet can be linked to external networks, including traffic control, vehicle depots and the internet. Using a standard protocol increases reliability and economy, which is essential for widespread introduction of the technology across Tokyo's rail network.

Complex features of modern trains such as automatic train protection, power doors and brake controls introduce additional potential for failure. On the busy, high-frequency lines in the Tokyo area, a failed train can cause immense operational problems. For this reason it is usual to provide redundancy in on-board systems, but this is at the expense of additional cost and weight. On the ACT information technology has been harnessed to provide mutual support between multiple components so that if one fails, another immediately provides back-up.

The widespread introduction of electronic control systems has in practice meant that making judgements about the condition of the train and carrying out temporary repairs have become more time-consuming than with traditional technology. With the ACT a self-examination function is provided to check for faults, notifying the driver of potential problems. Components are continuously monitored, with diagnostic data transmitted to staff in traffic control centres and the maintenance depot.

Each vehicle has large passenger information displays, and some seats are fitted with internet-linked touch panel LCD screens or personal computer sockets. Passengers can also access the internet and e-mail using mobile telephones. Various on-board information services suitable for passengers with sight and hearing difficulties are provided. The displays can show train running data from traffic control centres, tourist information, news and advertisements. Closed circuit television cameras are fitted to enhance passenger security.

Assembly of the first five-car trainset was completed in January, and reliability testing is now taking place on Tokyo's Kawagoe and Chuo lines. Series production of the next generation of Tokyo commuter trains will begin once the testing is completed in two or three years' time.

TABLE: Specifications for JR East's Advanced Commuter Train

Cars 5

Gauge 1067mm

Formation 2 motor+ 3 trailer cars

Length mm

Driving car 16500

Intermediate car 13400

Width mm 3000

Power supply 1·5 kV DC

Traction motors 4Continuous rating per motor 200 kW

CAPTION: Top: JR East's prototype Advanced Commuter Train was completed in January and is now undergoing trials on the Kawagoe and Chuo lines

CAPTION: Above: Fig 1. Articulation allows the use of short, wide bodies for the intermediate cars

CAPTION: Left: Fig 2. Each traction motor on the ACT has its own VVVF inverter

CAPTION: Fig 3. ACT has an array of communications using an on-board ethernet

CAPTION: ACT features direct drive permanent magnet synchronous motors where the rotor is fixed to the axle

Advanced Commuter Train pioneers changes on Tokyo's commuter network

The Advanced Commuter Train is being developed as East Japan Railway's next generation of Tokyo suburban EMU. Now undergoing testing, ACT uses an on-board Ethernet to control traction motors, monitor critical components, and give passengers access to the internet and real-time train running information. The use of industry-standard information technology aims to reduce operating costs and increase reliability. Articulation allows a wider car body, and double-skin stainless steel or aluminium body panels simplify construction.

L' Advanced Commuter Train, pionnier des changements sur le réseau de Tokyo

L'Advanced Commuter Train est en cours d'élaboration pour devenir la nouvelle génération d'automotrices électriques de East Japan Railway pour le réseau de banlieue de Tokyo. Actuellement en essais, l'ACT utilise un équipement Ethernet embarqué pour la commande des moteurs de traction, la surveillance des composants vitaux et pour donner aux voyageurs un accès à l'Internet et aux informations en temps réel sur la circulation des trains. L'utilisation d'une technologie d'information standard, du type de celle utilisée dans l'industrie, a pour but de réduire les coûts d'exploitation et d'accroître la fiabilité. L'articulation autorise des véhicules plus larges et des caisses à panneaux en acier inoxydable à double face ou en aluminium simplifient la construction

Advanced Commuter Train nimmt Veränderungen am Tokyoter Vorortsnetz vorweg

Die Entwicklung des Advanced Commuter Train (ACT, fortschrittlicher Vorortszug) gilt als East Japan Railway's nächste Generation von Triebzügen für das Vorortsnetz von Tokyo. Der zur Zeit einem Testprogramm unterzogene ACT benutzt ein lokales Ethernet zur Steuerung der Traktionsmotoren, zur Überwachung kritischer Komponenten, und es dient zudem um den Reisenden Zugang zum Internet und Zugsinformationen in Echtzeit zu bieten. Der Einsatz von Standard- Computerkomponenten hat das Ziel die Betriebskosten zu reduzieren und die Zuverlässigkeit zu erh