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the city suburbs has been steadily increasing (рис. 14), almost doubling in these ten years, at a rate exceeding that of the population growth.

The peculiarity of this transport demand lies in the fact that it is concentrated in the morning and evening commuting hours. As a matter of fact, in these commuting time zones of four hours, as much as 50 per cent of the total passengers are carried. Naturally, the urban traffic problems must be solved with the massive traffic of commuting hours taken as the focal point.

Be that as it may, the passengers carried in and around Tokyo number as many as 30 million a day, or 30 per cent of the total passenger traffic of the nation. Its growth rate has been so high as to exceed the ever-expanding transport capacity, to crowd up all sorts of conveyances.

Thus, urban traffic has become one of the biggest problems facing the nation today.

1.2 Transport modes in and around Tokyo and the Railways

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As to the means of transport in and around Tokyo, there are railways, surface electric cars, trolley buses, omnibuses, and motorcars. Shares of these transport mean in the total traffic volume are illustrated below (табл. 4). The railway occupies 64% far exceeding the average nation-wide percentage of 45%, Accountable for this is that the railway network in and around Tokyo is well developed, as well as that of the railways, as explained later on, is most suitable for service in urban areas, because of its ability to carry on mass trans-

port with great punctuality.

Таблица 4

The railway when compared with other surface transport media is superior in mass transporting capacity, accuracy in service and safety in operation. It is, on the other hand, inferior to the others in branching — off ability and extending capacity. However, when we consider that the traffic demand is concentrated in fixed commuting time zones, as stated before, and the passengers' traveling distances are more or less unchanging, — that is, they are season-ticket travelers, we can easily conclude that what is most required of a transport means in urban

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areas is its mass transporting capability and speed.

Comparing the transport capacity of a railway route and a motorcar transport route, we find the former is far superior to the latter. For against the railway's 100,000 passenger/hour, it would take motorcars of 100-passenger capacity to be run every 30 seconds to produce 12,000 passenger/hr. The railway thus is incontestably superior to the motorcar in transporting capability in per area unit occupied.

Then, the scheduled speed of each transport mode during the commuting hours in and around Tokyo is a vital factor in that it determines the extent of the city make-up. The fact that the speed of the commercial bus is about 15 km/h against the railway's 30/40 km/h (табл. 5) goes to show that the railway is the most fitful means of mass transport for passenger service in Tokyo and its environs, capable of satisfying the transport demand most effectively.

This is clear from the sprouting out of apartment complexes in the suburbs of Tokyo, too. How that a city is developing centrifugally along the railway, the

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demand on the railway is expected to grow more and more. 1.3 Transport energy and cost

It is not easy to compare strictly the energy consumption by various transport modes, as different kinds of motive power and transporting system are used. But, when the electric rail-car railroading and the motorcar transport in Tokyo and its vicinity are compared, we find the energy consumption of an electric railcar to be 15 kcal/passenger km against a commercial bus's 60 kcal/passenger km, only about one fourth.

The transport cost is an important factor too in making a comparative study of various transport modes. Although the cost largely fluctuates depending on the price of land, the extent of facilities used, and the utilization efficiency of the rolling stock, we find the transport cost of the railway is about one fourth of that of the motorcar (табл. 6).

In this comparison, nation-wide averages are taken. As the land price is extremely high in Tokyo and its environs, the transport cost would be much higher than is given in the table for a transport mode with a capacity low in terms of per area unit occupied.

All this goes to show that it is more advantageous to boost the transport capacity of railways than that of any other mode in urban areas.

For railway transportation, usable are various forms, such as locomotivehauled trains, diesel railcar trains and electric railcar trains. However, as a great number of passengers are to be carried for comparatively short distances in urban traffic, it is necessary to use a means of transport that satisfies the following

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conditions:

(1)To carry on frequent service, the rolling stock to be used must have a high acceleration and deceleration characteristic.

(2)The rolling stock must have a high transport capacity per area unit oc-

cupied.

(3)The rolling stock should inflict less public nuisance — that is, make less noise and not pollute air by its exhaust

All these taken into consideration, it can be said that none other is more suitable for urban service than the electric railcar train.

So it is that the train service in our cities and their suburbs are performed almost exclusively by electric railcar train. JNR has about 4,000 and private railways 3,000 electric railcars put into service to meet the demand in and around Tokyo.

2.Transportation in Tokyo and Its Surrounding Areas

2.1Ground facilities

For traction, used in Tokyo and its environs is the direct current of 1,500 volts. The facilities set up in this connection are summarized below.

1). JNR-owned power generating facilities

Electricity used for train operation in Tokyo and environs is mostly supplied by JHR-owned power generating plants, comprised as at the end of March, 1967, of the Ojiya and the Senju Hydraulic Power Plants on the Shinano River system, producing 195,000 kilowatts, and the Kawasaki Thermal Power Plant in Kanagawa Prefecture, producing 210,000 kilowatts, totaling 405,000 kilowatts (рис. 15).

2). Transforming facilities for traction on commuting sections

The total extended length of the commuting sections (рис. 16) is about 370 km, served by 53 substations in all. Their total capacity is about 500,000 kilowatts, including that supplied for the traction of long-distance passengers trains and freight trains. Their maximum load per hour is about 250,000 kilowatts.

In order to supply power sufficiently for the fabulous commuter traffic mentioned before, the substations are spaced at about 6.9 km, the shortest span being 1.2 km. These are remote controlled from 14 control centers. There is a plan on foot to set up 18 additional substations and to turn all, including the existing ones, into unmanned substations for centralized control from 9 stations.

3). Catenary System

Now that current load has increased, the conventional simple catenary is being turned into the double simple catenary. The work is expected to be com-

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pleted before long. 4). Others

As more current is used for train operation, it has now become difficult to distinguish between fault current and traction current. To overcome the difficulty, JNR has a selective circuit breaker developed to distinguish fault current and, at the same, to enhance safety by using a system of linked breakers in combination. Also adopted are ATS (automatic train stop) and wireless for trains to prevent accidents in its attempt to ensure greater safety.

2.2 Rolling stock equipment

As a great number of passengers have to be carried speedily in a large city

and its vicinity, the rolling stock for commuter service and suburban service must be such as to have a high acceleration and deceleration power.

To meet such requirements, JNR has 101-series electric railcars developed. The outstanding characteristics of this type cars are:

(1)Two powered cars as a unit have eight traction motors in all, operated by one pilot controller.

(2)For high deceleration, the dynamic brake is used together with an automatic air brake in combination with an electromagnetic straight air brake.

(3)The rating of the traction motor is: terminal voltage, 375 V, 300 amperes, 2,450 rpm at the maximum weak field of 40%, output, 100 kw; a highspeed motor, indeed. The driving system is of the parallel cardan device with hollow shaft and a large gear ratio.

(4)To facilitate passengers boarding and alighting, the car has four biparting doors on one side, each with a width extended to 1,300 mm.

This 101-series electric railcars are operated at present in Tokyo and its vicinity in a 6M 4T consist of 10 cars (6 motive cars and 4 trailers) (рис. 17).

Lately, a 103-series type of higher quality which is more economical to operate, has been developed. Though basically the same as the 101-series type, it has a traction motor of 110 kW, and the cars are operated in 8-car consist, M:T

=1:1 as the standard. The acceleration and deceleration rates would generally vary depending on the load. As this would give rise to a problem in shortening the train intervals, the 103 series car compensating device equipped produce a given rate of acceleration and deceleration, regardless of the load.

Also for suburban service, JNR has a 1ll-series electric railcar developed. Produced to be used during commuting hours as well, it has three bi-parting doors. Its compartment is of semi-cross seats.

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JNR Route Map and Transmission Line in Tokyo Area

Commuter Sections (JNR’s own power)

Commuter Sections

(Purchase from power companies)

Electrified Sections except commuter sections (JNR’s own power)

Electrified Sections except commuter sections (Purchase from power companies)

Non – electrified Sections

JNR’s own power transmission lines (140 kV)

JNR’s own power transmission lines (60 kV)

JNR’s own power plants JNR’s own substations Substations of power companies

Рис.15

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Its main electric equipment and power transmission system are the same as those of the 101-series car, though its gear ratio is made 1:482, against the 101-series 1:560, for operation at higher speeds. The standard is 6M 5T but with a 2M 2T supplementary consist, the train of these cars are operated in a long consist of 8M 7T (табл. 7).

As is clear in the table, over 12 cars are put into operation on the average for each route km in the commuting sections of Tokyo and its vicinity. On the Yamate line, the number is as many as 16 cars per km. This goes to show how efficiently the electric railcars in Tokyo and its vicinity are operated.

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2.3 Train operation

As explained before, with the improvement in the acceleration power of commuter type electric railcars, it has become possible to operate trains at shorter intervals. As a matter of fact, the trains on the Yamate line are operated at the minimum headway of 2 minutes. However, as it is impossible to run trains at such a headway, JNR has its block section for commuter traffic considerably shortened.

When only electric railcar trains are run, as on the Yamate line, a short length of block section presents no problem at all. However, when ordinary trains are run as well, as on the Chuo line (рис. 16), a short block section won't do because of the braking distance required of such trains. So, a device for detecting kinds of rolling stock is installed in such a way as to let the electric railcar train alone enjoy the advantage of a short block section.

2.4 Commuter service improvement projects under the Third Long-term Plan of JNR

The transport demand in urbanized areas is growing so rapidly, JNR is now confronted with the urgent problem of how to deal with the commuter traffic. Under the First and Second Long-term Plans, JNR invested some 72,500 million yen in its attempts to improve its track facilities, station facilities and electric installations, as well as to increase the number of rolling stock for longer train operation, so as to reduce the train headway (табл. 8).

Таблица 8

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Notwithstanding, however, the influx of population into urban areas has continued with greater intensity to worsen the urban traffic. The congestion has so worsened that no plan for transport capacity boosting centering around rolling stock alone suffices. The time has come for a drastic step — construction of additional tracks as the basic requirement for service improvement.

JNR, therefore, came up with a Third Long-term Plan, aiming at the improvement of commuter service as a target, earmarking 520,000 million yen (400,000 million yen for. ground facilities improvement included) for investment to turn all the tracks in Tokyo and its vicinity, for commuter traffic as well as others, into quadruple and triple tracks.

This drastic step will surely expand JNR's transport capacity to an enormous extent. However, when we consider the transport demand that is expected to soar in the future, this will, on its completion in 1971, reduce the present congestion rate of 300% to only 240% per rush hour.

The main problems in the way of improving urban traffic are —,

(1)The utilization efficiency of rolling stock and electricity is deplorably low, because of the high rate of transport demand concentration, requiring the massive commuter service to be performed during only three or four hours a day.

(2)The high cost of land requisitioning for additional tracks in urban ar-

eas.

These two problems must by all means be tackled and overcome as part of a city administration policy in order to deal most effectively with urban traffic.

3.Urban Transportation System and Energy

3.1 Commuter service and power consumption

The daily current load on JNR-owned power plants, both hydraulic and thermal, in and around Tokyo for commuter service (рис. 17) reaches about 350,000 kilowatts at the peak in the morning and evening, dropping as much as to about 100,000 kilowatts at midnight.

To cope with such an inefficient load factor and worst fluctuation in demand, JNR has two 1,880,000 cubic meter regulating reservoirs set up at the Ojiya and Senju Power Plants. The excess volume of water at midnight is stored up here to cover up the shortage at the peak hours. When the water still runs

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