On-board condition monitoring keeps down Series E231 costs
BYLINE: Yoshihiko Sato
General Manager, Transport & Rolling Stock Department East Japan Railway Co
East Japan Railway's Series 209 broke fresh ground in 1992 when it was launched as a train designed to halve costs. The idea was to achieve major savings in manufacturing and operating costs through a shorter life cycle and lower car weight. As the concept developed, further trains were added to the family, including Series E217, 127 and 701. Over 2000 EMU cars have now been built.
From 1997 JR East began to develop the Series E231 as a successor to Series 209 to take advantage of the latest advances, especially in information technology. A prototype built in 1998 was used to confirm performance and reliability. Series production started in 1999 and delivery of the first batch began this February. In the next four years JR East will assemble over 1000 cars, leading to further cost savings and higher standards of passenger service.
Every day JR East operates 400000 train-km on its 1067mm gauge Tokyo commuter network, 25% more than when the company started out 12 years ago. Overcrowding has been reduced by the introduction of trains with higher capacity and an increase in service levels, cutting the average number of passengers per car in the peak hour from 333 to 288.
In contrast to other operators, JR East has never increased its fares, apart from adding value added tax. As a result its services are cheaper than those of other operators, making them very competitive. New low-cost trains contribute to this strategy and attract passengers too.
Series 209 had lightweight stainless steel bodyshells, bolsterless bogies, lightweight gears and interior structures, asynchronous motors with GTO thyristor control and equipment monitoring systems. Costs were cut by 30% and weight by 20% - it is clear that the half life is possible in economic terms but not physically. The physical lifetime of Series 209 is now being evaluated.
Initial batches of Series 209 ran on the Keihin-Tohoku line, and Series E217 followed on the Yokosuka-Sobu line. Trains in this family now form one-quarter of JR East's Tokyo commuter stock, and energy consumption has been halved compared with the earlier Series 103 sets. Series 209 was assembled from 1994 by JR East at its former Niitsu maintenance workshop in conjunction with Tokyu Car Corp, and employees were retrained from maintenance to car production.
Compared with the original Series 209, Series E231 has been designed to increase capacity by 5%, and cut manufacturing and maintenance costs by 10%. Computer networks were installed to supervise and control on-board equipment, and IGBT technology to give better performance. A 10-car air-conditioned unit costs 8% less to build than Series 209 and consumes half the energy of earlier designs. The cars are 20m long, with an internal width of 2·75m.
Information technology has been developed for greater modularity and to permit self-checking of components. Known as the Train Information Management System, this has reduced cabling between cars by 80% and wiring on each car by 35%. TIMS uses 32-bit CPU central control units on driving trailers with terminal units on each car. Each unit is connected by buses laid out in a ladder network to ensure tolerance of faults.
Before starting a train from a depot, a driver must check its running gear, cab equipment, marker lights, pantographs, doors and brakes. TIMS has sensors on the marker lights, pantographs, doors, switches and air-cylinders to check their status automatically, cutting the inspection time from 30 min to just 5 min.
Until now, running gear for short-distance commuter trains differed from that used for outer suburban trains because of different stopping patterns and running speeds. Series E231 can be used for both applications. Maximum speed is 120 km/h, and its acceleration and the speed-tractive effort characteristics can be modified by software installed in the VVVF inverters. New 95 kW traction motors were developed to allow a higher rotating speed while ensuring compatibility with Series 209 and E217.
The Series E231 was designated as Series 209-950, and Niitsu and Tokyu Car each completed half a train by October 1998. They were able to carry out design using computer networks that directly linked engineering staff in each company, 400 km apart. The prototype was a 10-car set with four motor cars, two driving trailers and four trailers, one of which had six doors on each side. After tests and driver training, it entered service on the Chuo-Sobu line in March 1999. There were no major problems, although there were minor incidents involving the door systems and auxiliary power supply. Experience gained with the prototype allowed the design to be refined for series production.
CAPTION: Series E231 deliveries began in February, and the trains are now operating on the Tohoku-Takasaki (above) and Chuo-Sebu lines