BYLINE: Kazuhiro Igarashi and Tsuneo Maruyama *

BYLINE: * Kazuhiro Igarashi is Chief Engineer in the Technical Research & Development Division of Central Japan Railway, and Tsuneo Maruyama is Chief Manager of the Technical Development Promotion Department at West Japan Railway

NEXT MARCH will see the launch of revenue services using a production build of Series 700 shinkansen trainsets, developed jointly by JR Central and JR West. Following a year of intensive testing with the prototype, JR Central has ordered a build of 17 trains which are to enter service over the next three years. The first four sets are to be completed in the current fiscal year, for the start of operations in the spring.

Behind the Series 700 project is the trend towards deregulation, which has seen the entry of new airlines, liberalisation of air fares and increases in capacity following airport expansion. This has increased the commercial pressures on the Tokaido and Sanyo Shinkansen, demanding further improvements to the quality of rail services to strengthen their competitive edge.

As explained in RG 5.97 (p311), the joint development for the Series 700 was intended to produce a train costing about the same as a Series 300 (Nozomi), but with more comfortable passenger accommodation in terms of both ride comfort and interior design. It also had to offer improved performance and lower operating costs, while at the same time having less environmental impact.

While the Series 300 highlighted an increase in top speed, the Series 700 emphasises superior performance through the introduction of new technologies. No further speed increases are envisaged on the Tokaido Shinkansen, because the benefits would not justify the investment. Running speed is limited by the small curve radii, and the high cost of upgrading the infrastructure for a maximum speed of more than 270 km/h would not offer significant savings in travel times. On JR West’s Sanyo Shinkansen where the curve radii are larger, the target speed was set as 285 km/h.

One of the advantages of joint development has been access to the technology and experience of all the partners involved. Series 700 draws on JR Central’s Series 300 and the 300X project, and on JR West’s Series 500. Another advantage is the reduction of production costs through an increase in order volume leading to economies of scale in manufacturing. At the same time we have been able to spread the development costs between the partners.

Testing proves the concept

Running tests with the prototype trainset began in October 1997, and by April this year the first round of performance confirmation tests on the Tokaido and Sanyo Shinkansen had been completed. These tests included running stability, acceleration and braking performance, current collection performance and the strength of the body and parts. Ground-based testing covered catenary performance, substation characteristics, track and structure loadings, wayside noise, ground vibration and micro-pressure waves in the tunnels.

In terms of ride comfort, interior noise, bodyshell strength, and tunnel micro-pressure waves, the conditions were more demanding on the Sanyo Shinkansen, which has a higher proportion of slab track and tunnels than the Tokaido Shinkansen.

Satisfactory results were obtained at speeds up to 310 km/h on the Sanyo Shinkansen, confirming that the Series 700 is far superior to the Series 300 in terms of ride comfort and interior noise. Contributing to this improvement are various innovative technologies. These include dampers between adjoining car bodies and a semi-active vibration control system to improve ride comfort, extruded aluminium alloy bodyshells using a double-skin structure filled with sound-insulating material to reduce interior noise, and IGBT-based traction controls which allow power switching at higher frequencies.

From an environmental perspective, improvements on the Series 300 result from noise-reduction technologies such as the ’aero-stream’ nose, the simple structure of the single-arm current collector, and the roof-mounted insulator cover with side walls.

Following initial trials, the prototype Series 700 embarked on a programme of long-term endurance running on the Tokaido and Sanyo Shinkansen. This is intended to study the durability of the cars and collect data to establish maintenance standards. Over the summer of 1998, we confirmed the stability of the traction power devices at higher temperatures and the performance of the air-conditioning equipment.

Later this month, once the train has achieved 250000 km of test running, some of the power devices and the bogies will be removed to check deterioration, wear and dirt. This will provide an input into the development of car maintenance standards and frequencies. o

CAPTION: Above: This month the Series 700 prototype, seen here crossing Lake Hamana, will complete 250 000 km of test running

Inset: Series 700 uses a newly-developed single-arm current collector to reduce aerodynamic noise

CAPTION: Below: The prototype is equipped with a wide range of measuring instruments and recorders