System Dynamics '95 — Volume II
System Dynamics Model of the Tokyo Subway System
Takahiro Kojima Senshu University
Yutaka Takahashi Gakushuin University
Kinya Machida Surugadai University
Teiichilgarashi Teito Rapid Transit Authority
Abstract
Tokyo and the surrounding region support a huge population. The resulting large number
of people who commute to the city centre has necessitated the ongoing construction and
maintenance of a vast railway network. Currently transportation from terminal stations
to the city centre is provided mainly by Japan Railways’ Ymanote Line, the TRTA and the
Tokyo Public Subway. Thirteen lines, including those in only partial operation, comprise
the subway system in the downtown area. The TRTA forms the heart of the system, with
nine lines, while the Tokyo Public Subway is relatively small in scale, with only four lines.
The current research project provides the TRTA material for use in developing future
management directions by data provided by the TRTA. This paper covers the first phase of
this research.
Introduction
The Teito Rapid Transit Authority (TRTA) was established on July 4, 1941. Today, it is the
largest subway operator in Tokyo, with a network of eight lines covering a distance of
162.2 km. It provides a fast, safe and convenient mode of transport for the six million
people that travel on its lines everyday. This figure represents 80% of subway passengers.
Number of Employees: 10,772
Number of Stations: 148 (20 above ground)
Number of cars: 2,313
Ginza Line: 222 Marunouchi Line: 338
Hibiya Line: 336 Tozai Line: 480
Chiyoda Line: 369 Yurakucho Line: 360
Hanzomon Line: 176 Namboku Line: 32
Average passenger load per day : 5,920,000
Average ticket revenue per day : 647 million (yen)
Average distance traveled per passenger: 7.4 km
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The history of subways in Tokyo began back in 1927 when a 2.2 km stretch of line was
opened from Asakusa to Ueno. This private company enterprise was not only the first
subway in Japan, but in Asia. The entire line, now known as the Ginza Line, was
completed in 1939, extending 14.3 km, from Asakusa to Shibuya.
In 1941, when TRTA was founded, the transportation system in Tokyo consisted of the
Ginza line, the Japan National Railway's (JNR) Yamanote and Chuo lines, suburban
trains operated by private companies and municipally run a streetcar network. As
economic activity increased and the population grew, streetcars could no longer cope with
the city's transportation needs. Buses and taxis began to crowd the roads, calling for a re-
examination of urban transit operations.
As public demand for a coordinated transportation system increased, Reorganization of
Land Transportation Undertakings Law was passed in 1938. As a result of this law, TRTA
was established and assigned to construct subways in Tokyo and the surrounding area.
There are at currently two subway operators in the Tokyo area, the Teito Rapid Transit
Authority (TRTA) and the Transportation Bureau of the Tokyo Metropolitan Government
(fBTMG), TBTMG began operating lines in 1960 and has constructed four lines to date.
Together these operators run an impressive 12-line mass transit network, that is receiving
increasing recognition as one of the world's most developed subway systems.
Capital
In the early years, TRTA was financed by both the National and Local Government and
private business. However, in 1952, TRTA eliminated its private capital to receive
additional government funding. It has been financed by the National Government and the
Tokyo Metropolitan Government ever since.
<As of March 1993>
Capital: ¥58.1 billion
National Government: ¥31 billion (53.4%)
Tokyo Metropolitan Government: ¥27.1 billion (46.6%)
Revenues and Expenditures
Year 1990 1991 1992 1993*
Revenues 254.1 1273.0 286.7 338.5
Expenditures _|249.0 269.7 1286.5 341.9
*cf 1993 profit and Loss statement
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Construction of New Lines
TRTA must apply to the Minister of Transportation for a license to construct new lines.
The Minster then turns to the Transportation Policy Deliberation Council. This Council
acts as an advisory organ to the Minister regarding the formulation of basic policies with
the aim of establishing a comprehensive transportation system.
In July 1985, the Council submitted Transport Policy Report No.7. This report calls for the
establishment of a 13-line rapid transit railway network in Tokyo by the year 2000. The
railway network is characterized by its plan to efficiently connect the constantly growing
suburban ‘housing areas to the central business districts .
The flow chart below illustrates the procedure for authorizing rapid transit network plans
based on the Metropolitan Plan Act.
Construction Methods
Of the eight subway lines operated by TRTA, seven were constructed by the Authority
between 1951 and the present day. This period has seen remarkable progress in tunnel
construction technology worldwide. Japan, in particular, has played a major role in the
development of such in high-density areas. Construction methods employed by TRTA have
been Cut-and-Over Method (1950 to 1985) and Shield Method (since 1985).
Through- Services
The subways were initially planned to replace the streetcar network, and passengers
traveling into the center of Tokyo from the suburbs had to change trains at the terminal
stations. However, as the number of passengers increased, these stations became more
and more congested. An idea put forward to solve this problem was to create through-
services with JNR and private railway lines.
The first subway line to provide through-services was the Hibiya line. This line was
opened just before the Tokyo Olympic Games in August 1964 and operates through-
services with the Tobu Isesaki line and the Tokyu Toyoko line. The Ginza and Marunouchi
lines, the first of the twelve subway lines to be built, do not provide through-services due
to differences in current collector methods and track gauges. However, seven lines have
been connected to JNR and private suburban lines at twelve points. With the expansion of
Tokyo's boundaries, the subways’ through-service operation has increased in distance.
They now extend to some 50 km from the city center.
RESULT :
1. From the standpoint of the passengers traveling into the city center from the suburbs,
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the inconvenience of changing trains was eliminated and service thereby improved.
2. Through-services provided the answer to the private railways efforts to gain access to
central Tokyo.
3. Huge investments were required to build new subway lines in the city center. The
through-services would guarantee a fairly large passenger demand for the subway from
the very start.
Greater Tokyo
With more and more people squeezing into the suburbs, Tokyo continues to grow.
According to the 1990 census, some 8 million people live within the city limits, a figure
that has not significantly changed since 1960. However. in the same 30 years the
population inside a 50 km radius from the city center has.swelled from 15.5 million to 28.6
million,
According to a 1990 transportation census, the number of people in the Tokyo
metropolitan area commuting to work and school by public transport was approximately
9.5 million a day. This is an increase of 1.4 million (17 %) when compared to the previous
census (1985). As much as 30 % of this volume is concentrated in just one hour during the
commuter peak period.
According to this census, the average distance traveled by commuters to work and school
is 26 km and the average travel time is 68 minutes. Specially noteworthy is the huge daily
inflow of passengers from Saitama and Chiba prefectures, numbering 960,000 and 810,000,
respectively, a trend which is conspicuously increasing.
TRTA is dedicated to expanding and improving its network. Since 1955, the subway
system in Tokyo has expanded more than 10 times in total track length and approximately
17 fold in passenger volume.
Conclusion
Our work on the model of the TRTA is currently in the early stage. At present, it predicts
the change in passenger load resulting from various factors and accompanying change in
TRTA revenues and the shift in passenger load and change in revenues resulting from the
opening of new lines. Our first step in creating the model was to develop a sub model that
would predict the passenger load.
In the past, we tried several times to reflect statistical data in the SD model. We were
unsuccessful because the model was structurally dependent on the initial value. Recent
advances in SD model development tools, however, have now made it possible to reflect
statistical data.
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System Dynamics '95 — Volume II
Figure 1 displays data on past and predicted passenger load. The number 1 indicates the
value predicted by SD model simulation. The number 2 indicates actual result data is from
table function. The actual result data is from only the first 10 periods after the beginning
of the simulation. Beyond that only predicted values are shown. There a good match
between the predicted value and the actual value. The delay functions and smooth
functions were used arrive at the predicted value. However, the table function, which
directly reflects the prediction, was not used.
Figure 1.
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References
1) Teito Rapid Transit Authority “‘93 TRTA Hand Book”
2) Kameyama,S. Kojima, T. Uchino, A. Machida, K. “ Accounting Measurement and
Methodological Characteristics of Accounting Dynamics” Milling, P. M. Zahn, E. O.
(Eds.) 1987 Spring-Verlag “Computer-Based Management of Complex Systems”
pp. 111-118
3) Kameyama, S. Kojima, T. Uchino, A. Machida, K. “ The Feedback of Accounting
Dynamics“ Saeed, K. Andersen, D. F. “ Proceedings of the 1991 International
conference of the System Dynamics Conference” pp. 738-743
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Appendix
Profit and Loss Statement
(From April 1,1993 to March 31,1994)( Million yen)
Ordinary Profit and Loss
(Operating Revenues and Expenses)
I
Railway
Operating income 263,813
Operating expenses 218,776
Operating profit
Operating profit from related businesses
Operating income 8,221
Operating expenses 2,445
Operating profit from related businesses
Operating profit from all businesses
(Non-operating profit)
I
Vv
Non-operating income
Non-operating expenses
Interest expenses 53,059
Others 1,526
Ordinary profit
Extraordinary profit and loss
v
VI
Special profit
Subsidies 62,874
Others 5,405
Special loss
Loss due to reduced value of subsidies 60,954
Other 5,200
Gross profit
Corporate tax refund
Profit for the period
Surplus at the beginning of the period
Undisposed profit for the period
626
45,037
7716
45,813
3,198
54,585
-5,574
68,280
