Tōzai Line (Tokyo Metro)

thumb|Tokyo Metro Tōzai Line train pulling into [[Waseda Station (Tokyo Metro)|Waseda Station in 2015]]

The is a rapid transit line in Tokyo and Chiba Prefecture, Japan, owned and operated by Tokyo Metro. The line runs between Nakano in Nakano-ku, Tokyo and Nishi-Funabashi in Funabashi, Chiba Prefecture.

The Tōzai Line was referred to as Line 5 during the planning stages; the seldom-used official name is .

In 2024, the line carried a daily average of nearly 1.5 million passengers, making it the busiest line on the Tokyo subway network. On maps, diagrams and signboards, the Tōzai Line is shown using the color "sky blue" and its stations are given numbers using the letter "T".

Overview

The line runs through central Tokyo from east to west via Takadanobaba, Waseda, Ōtemachi, Nihombashi, Kiba and Urayasu. It was opened as a bypass route for the Chuo Rapid Line and the Sobu Line, which were heavily congested at the time. It is the only Tokyo Metro line to extend into Chiba Prefecture (although the Shinjuku Line operated by Toei also extends into Chiba Prefecture.) It also runs above-ground for from to , nearly half of the line and longer than any other railway line in the Tokyo subway network.

The Tōzai Line features through services at both ends of the line. Trains run onto the JR East Chūō-Sōbu Line for at the western (Nakano) end, and onto either the Chūō-Sōbu Line for or the Tōyō Rapid Railway Line for at the eastern (Nishi-Funabashi) end.

According to the Tokyo Metropolitan Bureau of Transportation in 2018, the Tokyo Metro Tōzai Line continues to be most crowded subway line in Tokyo, and the most crowded train line in all of Japan, with its peak running at 199% capacity between and stations. Women-only cars were introduced on the line for use during morning rush hour on November 20, 2006.

During the COVID-19 pandemic, peak ridership dropped from a rate of 199% in 2019 to 123% in 2020.

History

Early years

The original plan for what is now the Tōzai Line was included in a report by the Tokyo City and Area Transportation Research Committee (東京市内外交通調査委員会), which was established within the Ministry of Home Affairs in 1917. The proposal outlined a route connecting “Ikebukuro – Takadanobaba – Iidabashi – Otemachi – Susaki”.

In 1920, a construction patent for this route was granted to the Tokyo Railway (東京鉄道). However, following the Great Kantō Earthquake of 1923, the patent was revoked along with those for other planned lines because construction had not yet commenced.

The route license for the Tōzai Line originates from the six municipal subway lines planned by Tokyo City, the predecessor of today’s Tokyo special wards, prior to World War II. The license was granted on May 16, 1925, under Ministry of Home Affairs Notification No. 56 of 1925 (大正14年内務省告示第56号).

The present Tōzai Line corresponds to the former Line 5, which was authorized as a 14.2-kilometer route running from “Ikebukuro – Waseda – Iidamachi – Hitotsubashi – Tokyo – Eitaibashi – Susaki”. and the remainder opened in stages until its completion in 1969. Through service with the then Japanese National Railways (today part of the JR Group) – a first for a Tokyo subway line – began in 1969 connecting the Chūō and Sōbu lines. This is a rare situation in Tokyo, as the only other subway line with through services onto JR lines is the Chiyoda Line.

Due to a surge in ridership on the Tōzai Line, the Teito Rapid Transit Authority (TRTA) introduced 12 new-build 5000 series cars and transferred 50 from the Chiyoda Line in 1981 in an effort to increase capacity on the line. Rapid residential development in the Urayasu and Kasai areas further increased demand. In response, TRTA introduced rapid trains that ran non-stop between and stations, and stopped at every station west of , in November 1986.

The Tōyō Rapid Railway Line, effectively an eastward extension of the line, opened in 1996. It nevertheless remains a private entity to which the Tōzai lines offers through services.

Chronology

March 16, 1966: The line is extended at both ends. It now runs between Nakano and Takebashi.
April 28, 1966: Through service to the Chūō Line of JNR commences as far as Ogikubo.
October 1, 1966: Takebashi to Ōtemachi section opens.
September 14, 1967: Ōtemachi to Tōyōchō section opens.
March 29, 1969: Tōyōchō to Nishi-Funabashi section opens and Rapid service begins (non-stop between Tōyōchō and Nishi-Funabashi).
April 8, 1969: Through service on the Chūō Line is extended to Mitaka, and through service begins on the Sōbu line to Tsudanuma.
April 8, 1972: Through service on the Sōbu Line is withdrawn except during rush hours.
1975: Another type of Rapid service is introduced, calling at Urayasu between Tōyōchō and Nishi-Funabashi.
October 1, 1979: Nishi-Kasai station opens.
March 27, 1981: Minami-Gyōtoku station opens.
1986: Commuter Rapid service is introduced, running non-stop between Urayasu and Nishi-Funabashi.
(April 1, 1987: JNR is privatised. The Chūō and Sōbu lines become the property of JR East.)
1996: The Rapid service that runs non-stop between Tōyōchō and Nishi-Funabashi ceases.
April 27, 1996: Tōyō Rapid Line opens between Nishi-Funabashi and Tōyō-Katsutadai. Through service begins.
January 22, 2000: Myōden station opens.
April 1, 2004: Teito Rapid Transit Authority (TRTA or Eidan) becomes Tokyo Metro.
November 20, 2006: Women-only cars are introduced during morning rush hours.

Services

The Tōzai Line was the first Tokyo Metro line on which express services run: two types of rapid trains skip some stations east of Toyocho. The Tokyo Metro Fukutoshin Line began services on June 14, 2008, and also features express services.

Through services to via the JR East Chūō Line and via the Tōyō Rapid Railway run all day. Outside of rush hours, only local trains run through to the Chūō Line and only rapid trains run through to the Tōyō Rapid Railway. During the morning and evening peak periods, through services run to via the JR East Sōbu Line.

Stations

center|thumb|900x900px|List of Tozai line stations

Local trains stop at every station. Rapid trains stop at stations marked "●" and do not stop at those marked "｜". Some weekday westbound trains do not stop at stations marked "↑".

{| class="wikitable" rules="all"

!rowspan="2"|No.

!rowspan="2"|Station

!rowspan="2"|Japanese

!colspan="2"|Distance (km)

!rowspan="2"|Comm. Rapid

!rowspan="2"|Rapid

!rowspan="2"|Transfers

!rowspan="2" colspan="2"|Location

!Between<br/>stations

!From Nakano

| colspan="10" align="center"|↑ Through-services to/from via ↑

|中野

| style="text-align:right;"| –

| style="text-align:right;" |0.0

| style="background-color:#afb; text-align:center;" |●

| style="background-color:#fab; text-align:center;" |●

|Nakano

| rowspan="17" style="text-align:center; width:1em; line-height:3;" |Tokyo

|落合

|style="text-align:right;"|2.0

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|rowspan="4"|Shinjuku

|高田馬場

|style="text-align:right;"|1.9

|style="text-align:right;"|3.9

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|早稲田

|style="text-align:right;"|1.7

|style="text-align:right;"|5.6

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

| (: SA30)

|神楽坂

|style="text-align:right;"|1.2

|style="text-align:right;"|6.8

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|飯田橋

|style="text-align:right;"|1.2

|style="text-align:right;"|8.0

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|rowspan="4"|Chiyoda

|九段下

|style="text-align:right;"|0.7

|style="text-align:right;"|8.7

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|竹橋

|style="text-align:right;"|1.0

|style="text-align:right;"|9.7

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|大手町

|style="text-align:right;"|1.0

|style="text-align:right;"|10.7

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|日本橋

|style="text-align:right;"|0.8

|style="text-align:right;"|11.5

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|rowspan="2"|Chūō

|茅場町

|style="text-align:right;"|0.5

|style="text-align:right;"|12.0

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

| (H-13)

|門前仲町

|style="text-align:right;"|1.8

|style="text-align:right;"|13.8

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

| (E-15)

|rowspan="4"|Kōtō

|木場

|style="text-align:right;"|1.1

|style="text-align:right;"|14.9

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|東陽町

|style="text-align:right;"|0.9

|style="text-align:right;"|15.8

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|南砂町

|style="text-align:right;"|1.2

|style="text-align:right;"|17.0

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|<nowiki>|</nowiki>

|西葛西

|style="text-align:right;"|2.7

|style="text-align:right;"|19.7

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|<nowiki>|</nowiki>

|rowspan="2"|Edogawa

|葛西

|style="text-align:right;"|1.2

|style="text-align:right;"|20.9

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|<nowiki>|</nowiki>

|浦安

|style="text-align:right;"|1.9

|style="text-align:right;"|22.8

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

|Urayasu

|style="text-align:center; width:1em;" rowspan="6"|Chiba

|南行徳

|style="text-align:right;"|1.2

|style="text-align:right;"|24.0

|style="background-color:#afb; text-align:center;"|↑

|style="background-color:#fab; text-align:center;"|<nowiki>|</nowiki>

|rowspan="3"|Ichikawa

|行徳

|style="text-align:right;"|1.5

|style="text-align:right;"|25.5

|style="background-color:#afb; text-align:center;"|↑

|style="background-color:#fab; text-align:center;"|<nowiki>|</nowiki>

|style="text-align:right;"|1.9

|style="text-align:right;"|30.8

|style="background-color:#afb; text-align:center;"|●

|style="background-color:#fab; text-align:center;"|●

| colspan="10" align="center"|↓ Through-services to/from: ↓

, via
Limited through-services to/from via

Rolling stock

Present

Tōzai Line trains are 10-car formations of -long cars, with four doors per side and longitudinal seating. The maximum operating speed is . Newer trains feature wide doors to allow for faster boarding times.

Tokyo Metro
05/05N series (since 1988)
07 series (since 2006) (transferred from Yūrakuchō Line)
15000 series (since 2010)
Tōyō Rapid Railway
2000 series (since 2004)
East Japan Railway Company (JR East)
E231-800 series (since 2003)

File:Tokyo-Metro Series05-122F.jpg|Tokyo Metro 05 series

File:Tokyo-Metro Series05-143F.jpg|Tokyo Metro 05N series

File:Tokyo-Metro Series07R-76.jpg|Tokyo Metro 07 series

File:Tokyo-Metro Series15000-15001.jpg|Tokyo Metro 15000 Series

File:Toyo-Rapid-Railway Series2000-2009.jpg|Toyo Rapid 2000 series

File:JRE Series-E231-800 K5.jpg|JR East E231-800 series

</gallery>

Past

Tokyo Metro
5000 series (from 1964 until 2007)
8000 series (from 1987 until 1988, temporary, built for Hanzōmon Line)
JR East
301 series (from 1966 until 2003)
103-1000 series (from 1989 until 2003)
103-1200 series (from 1971 until 2003)
Tōyō Rapid
1000 series (from 1996 until 2006)

File:Model 5000-Stainless Steel of Teito Rapid Transit Authority.JPG|5000 series with stainless steel body

File:Model 5000-Aluminum of Teito Rapid Transit Authority.JPG|5000 series with aluminium body

File:営団-8014.jpg|8000 series

File:301 K5 Mitaka 20030222.JPG|JR East 301 series in February 2003

File:Jnr 103-1200.jpg|JR East 103–1200 series

File:Tōyō Rapid 1008F.JPG|Tōyō Rapid 1000 series in September 2006

</gallery>

Depots

Fukagawa Depot (深川検車区)
Gyōtoku Depot (深川検車区行徳分室)
Fukagawa Workshop (深川工場)

Notes

a. Crowding levels defined by the Ministry of Land, Infrastructure, Transport and Tourism:

:100% — Commuters have enough personal space and are able to take a seat or stand while holding onto the straps or hand rails.

:150% — Commuters have enough personal space to read a newspaper.

:180% — Commuters must fold newspapers to read.

:200% — Commuters are pressed against each other in each compartment but can still read small magazines.

:250% — Commuters are pressed against each other, unable to move.

References

Shaw, Dennis and Morioka, Hisashi, "Tokyo Subways", published 1992 by Hoikusha Publishing

External links

Tokyo Metro website