Kosei Line (湖西線)
The Kosei Line is a railway line (arterial line) of the West Japan Railway Company (JR West) that runs between Yamashina Station in Yamashina Ward, Kyoto City, Kyoto Prefecture, and Omi-Shiotsu Station in Nishiazai-cho, Ika-gun, Shiga Prefecture. The entire line is included within the section of the metropolitan area and its suburbs. The line is part of the Nihonkai Jukan Line/Japan Sea Line (日本海縦貫線).
The line was called the Kosei Line because it passes through the Kosei area, which is the western coastal area of Lake Biwa. Although the Kosei Line starts at Yamashina Station, all local trains run through to Kyoto Station, and limited express trains from Osaka Station to Hokuriku or Tohoku and freight trains connecting Hokuriku or Hokkaido and Kansai or Kyushu pass the Kosei Line. Nagahara Station is the end of the Urban Network; the Kosei Line serves as a commuter line for passengers bound for Kyoto and Osaka since special rapid trains from Osaka and Himeji also run through the line.
ICOCA, Suica of the East Japan Railway Company (JR East) and TOICA of the Central Japan Railway Company (JR Central), as well as PiTaPa of KANSAI THRU PASS, can be used at all stations. J-Through cards can be used only at the stations between Yamashina Station and Omi-Maiko Station (J-Through cards can't be used at the stations between Kita-Komatsu Station and Omi-Shiotsu Station).
Administration (type of business): West Japan Railway Company (Railway Business Operator) and Japan Freight Railway Company (Railway Business Operator)
Track length (operating kilometers): 74.1 km
Track gauge: 1067 mm
Number of stations: 21 (including the stations at both ends of the track section)
Double-track section: Entire line
Electrified section: Entire line electrified (DC 1500V)
Block (railway): Double-track automatic block system
Operation direction center: Shin-Osaka integrated direction center
Maximum speed: 130 km/h
The Kosei Line between Nagahara Station and Omi-Shiotsu Station, which had been AC-electrified, was DC-electrified on September 24, 2006 as well as the Hokuriku Main Line between Nagahama Station and Tsuruga Station, and the special rapid train running through to Tsuruga Station on the Hokuriku Main Line has been partially operated since October 21, 2006 (described later).
All stations are managed by the Kyoto branch of the West Japan Railway Company.
Because the Kosei Line began as a high-speed railway and a short circuit connecting the Kansai and Hokuriku areas, tunnels and elevated bridges exist in many sections and there is no crossing on the Kosei Line. Previously, there were problems in that Onjo-ji Temple and Shirahige-jinja Shrine demanded compensation for passing the precincts of the shrine (although it was a tunnel); the local people opposed the construction; and the determination of tracks took time due to the relationship with Kojak (Kojaku) railway (江若鉄道) (described later); however, the minimum curve radius is basically set at 1,400 meters and the alignment (track) slope is set at no more than 19 per mill, which are high standards compared with existing railways.
In the planning stage of the Kosei Line, with the estimate that the track volume of the Tokaido Main Line would reach its limit, it was planned to construct a new line that would run from Yamashina Station to Nagao Station (Osaka Prefecture) on the Katamachi Line and to have freight trains enter a new Nagao yard and limited express trains enter Osaka Station from the Katamachi Line via the JR Tozai Line. Therefore, Yamashina Station is structured to branch off on the west side (construction of a new line on the west side was halted due to the severe fiscal conditions of Japan National Railways (JNR)).
Currently, the Limited Express 'Raicho (train)' and others travel at a maximum speed of 130 km/h through the entire line. The Limited Express 'Raicho (train)' (comprised of JNR/JR limited express Series 485), whose maximum speed is 120 km/h for its braking performance, is exceptionally permitted to run at a maximum speed of 130 km/h within the Kosei Line, where there is no crossing. The travel times of the Limited Express 'Thunderbird' are approximately 51 minutes from Kyoto Station to Tsuruga Station and approximately 53 minutes from Tsuruga Station to Kyoto Station.
Being suitable for high-speed operation, the Kosei Line was utilized for testing the speed improvement of the JNR/JR Limited Express Series 381, JR (West) Suburban Train Series 221, JR (Shikoku) Limited Express Series 8000, etc., beginning in the era of Japan National Railways (JNR).
After the establishment of JR West, the increase in maximum speed up to 160 km/h on the Kosei Line and within the Hokuetsu tunnel was examined, and at the same time the JR (West)/Hokuetsu Express' Limited Express Series 681 was manufactured as part of the plan; however, because of high costs for the improvement of railroad signals (e.g., installation of six-light signals on the Hokuetsu Express Hokuhoku Line) and the existence of low-speed local trains or freight trains and passenger trains pulled by electric locomotives, the travel time was estimated to be shortened by only 5 to 10 minutes, and consequently the operation at a maximum speed of 160 km/h was called off due to the low cost-effectiveness.
It is sometimes said that the running speed is 'as high as the Shinkansen,' but considering that the minimum curve radius is basically 2,500 meters on the Tokaido Shinkansen, which is a relatively low standard compared with other Shinkansen trains, it's impossible to operate trains on the Kosei Line at speeds equal to those of the Shinkansen.
Because the Kosei area is subject to heavy snows, as is the Hokuriku area, the Kosei Line is equipped with facilities such as sprinklers and gutters for snow drainage. Omi-Imazu Station has a storage-track facility, and a roof is installed at the location of a pantograph when cars are stored for protection from snowstorms.
Meanwhile, due to Hiraoroshi (strong winds from the mountains) the speed limit is often applied or the operation is regulated on the Kosei Line (in the past a freight train actually overturned while stopping), and the Limited Express 'Thunderbird,' etc., sometimes goes around via Maibara Station instead of passing the Kosei Line. Recently, windbreak fences have been installed on the Kosei Line (the details are provided later).
Freight trains, which pass the Kansai and Hokuriku areas, are frequently operated. Before the Kosei Line was opened, there was a plan to have freight transportation service between Katata Station and Omi-Imazu Station, but ultimately the plan was abandoned. Accordingly, all freight trains traveling on the Kosei Line pass through from Yamashina Station to Omi-Shiotsu Station without stopping (some trains stop to allow the passing of limited express trains, etc., for the sake of the schedule). The land for freight side tracks is now used for maintenance space or the like.
All stations are regarded as stops except for Otsukyo, Ogotoonsen, Katata, Omi-Maiko, Adogawa, Omi-Imazu and Nagahara, which have a passing station, and Makino Station, which has a home departure signal. The Kosei Line employed elevated structures with a slab track, and therefore large equipment was introduced for railroad maintenance. To secure space for the use of large maintenance equipment, a facility (which is parallel to a single track) was installed so as to have freight trains pass through the single track late at night. In the passing stations (except for Ogotoonsen Station and Makino Station), signal equipment, in which classification by the shape of turnout is available in both directions of inbound and outbound lines, was installed (block sections are provided on a double track but there is one block section on a single track). However, due to the decreased number of freight trains, it became less necessary to maintain the equipment, so the use of the signal equipment for the single track was stopped in 2004.
With taking account of operation on the single track, the Katata, Omi-Maiko, Omi-Imazu, and Nagahara stations have a structure that a passing track enters toward the inside along with scissor alignment, resulting in a track that's convenient for shuttle train service.
As part of the plan of Tsuruga Station and other south (west) of Tsuruga of the Hokuriku Shinkansen, there is an idea to modify the Kosei Line so that it can operate as a mini-Shinkansen.
Landscape along the Kosei Line
After leaving Yamashina Station, the Kosei Line branches off the Tokaido Main Line and enters the Nagarayama tunnel. This tunnel has a double-track cross section on the Nishiotsu side and a deformed tunnel of three single tracks on the Yamashina side. Local trains running on the inner track to Yamashina Station pass over the Tokaido Main Line at a slope of 18‰, while limited express trains and freight trains running on the outer track pass a branch track provided for a slope of 10‰ and join the Tokaido Main Line in the tunnel. Otsukyo Station approaches after passing through the Nagarayama tunnel. Passengers can change trains to Ojiyama Station of the Keihan Electric Railway.
After leaving Otsukyo Station, a train runs along long flatland created through an active fault on the north (the west coast of the Lake Biwa Fault Zone). Because the mountains of Hiei and Hira can be seen in the west and Lake Biwa can be seen in the east on almost every section of the Kosei Line, the line is known for its fine views. The Kosei Line is surrounded by serene countryside, but at the same time there are many residential areas and retail stores along the line to Katata Station. The track near Ogotoonsen Station is far from the old track of the Kojak (Kojaku) railway, and it passes straight through the mountainside. Accordingly, there are five relatively short tunnels (the Third Ogoto tunnel) around Ogotoonsen Station.
The Kosei Line after Katata Station runs along the lakeside, and on fine days passengers can enjoy mountain views on the opposite side of the lake. There are two relatively short tunnels (the first and second Kitakomatsu tunnels) after passing Kitakomatsu Station and then two short tunnels (the first and second Shirahige tunnels) to the north of the Shirahige-jinja Shrine (which had difficulty determining the track) and finally the Takashima tunnel (length: 1,488 meters), for a total of five tunnels.
The Kosei Line veers from the lakeside after Omi-Takashima Station and passes through the flatland. Omi-Imazu Station, which has a storage track, is a base station of the Kosei Line. Most of the local trains from Kyoto return at Omi-Imazu Station, while the coupling and decoupling of cars for special rapid trains departing from and arriving at Tsuruga Station are carried out at this station.
The Kosei Line further runs through the rice-paddy area and approaches mountains after Makino Station to pass through the Mineyama tunnel (length: 3,910 meters) and then the Shiroyama tunnel (length: 2,318 meters) after passing Nagahara Station. A so-called AC/DC dead section (a section in which power supply is cut off) existed on the north side of the Shiroyama tunnel until September 2006. The local trains returning at Nagahara Station still exist.
The Kosei Line passes over the rice-paddy area on the elevated bridge of about 20 meters in height, approaches the Hokuriku Main Line on the right hand side in the traveling direction and ultimately reaches Omi-Shiotsu Station.
Form of operation
According to the purpose of the short circuit connecting Kansai and Hokuriku, among the superior trains bound for Hokuriku, all the limited express trains 'Thunderbird (train),' 'Raicho (train),' 'Nihonkai (train)' and 'Twilight Express (train),' except for the overnight express 'Kitaguni (train),' pass the Kosei Line. Some limited express trains stop at Katata Station and Omi-Imazu Station to provide express service or accept commuters boarding between the Kosei area and the Keihanshin area. Some limited express trains stop at Otsukyo Station under the circumstances that superior trains to the Hokuriku Line used to stop at Otsu Station during the era of the Tokaido Line.
Meanwhile, the Kosei Line also serves as local transportation within the Kosei area, and various special rapid trains and local trains are operated on the Kosei Line. Although the Kosei Line starts at Yamashina Station, all the trains go through to Kyoto Station owing to the track facility of the station and the passenger flow, and some rapid and special rapid trains go through to Osaka and Himeji.
When the Kosei Line was opened, the local train would run only once an hour between Kyoto Station and Omi-Imazu Station or Nagahara Station; however, with the increase in the residential housing along the line the number of local trains has gradually increased. Because the number of passengers using the Kosei Line increased significantly at Katata Station and Ono Station, many local trains return at Katata Station or Omi-Maiko Station. The local train going through to Osaka Station via Kyoto Station is set, and a commuter train with four doors and long seats is also operated.
The special rapid train would go through to Katata Station from the Keihanshin area once an hour during the day when the Kosei Line was opened; the through-train service was later extended to Omi-Imazu Station. The number of special rapid trains operated during the day is greater than that during the evening rush, which is uncommon; currently, the special rapid train is operated five times an hour during the day and four times an hour during the evening rush. An outbound train from Kyoto Station runs only twice an hour between 7 and 8 a.m., which is remarkably infrequent.
The operation of the special rapid train is limited to the daytime, and the special rapid stops at every station to the north of Omi-Maiko Station. Accordingly, for commuters the rapid train from Omi-Imazu Station to Osaka Station running once during the morning (set on March 16, 1996) and the rapid train from Kyoto Station to Nagahara Station running once in the evening (set on March 8, 1997) were added (the former passes Shin-Asahi, Omi-Takashima and Kitakomatsu Stations, and the latter stops at every station to the north of Omi-Maiko Station; however, both trains have stopped at Ogotoonsen Station since March 23, 2002), and the operation of these trains has been extended to Tsuruga Station.
Meanwhile, the number of local trains running in the section between Omi-Imazu and Omi-Shiotsu was initially three per day, which is exceptionally few, due to the operation of few AC electric local trains, and also due to the fact that part of the section changed to the AC electrification between this section. The number of trains gradually increased after JR's ownership of the Kosei Line, and a through train to Fukui via Tsuruga Station and a train running toward the south from Omi-Shiotsu Station to Nagahama Station and Maibara Station on the Hokuriku Line were established after the electrification.
Consequent upon the extension of the DC section to Tsuruga Station, the operation of the special rapid train during the day was extended to Tsuruga Station with the schedule revision of October 21, 2006. Although the special rapid train is operated mainly between Omi-Imazu Station and Omi-Shiotsu Station during the morning and evening, some special rapid trains run through to Fukui or Maibara; the operation of rapid trains from the Kosei Line to Osaka during the morning and from Osaka to the Kosei Line is extended to arrive at and depart from Tsuruga Station during the evening. Through the above setting of the trains, the special rapid train has come to run almost once an hour during the day between Nagahara Station and Omi-Shiotsu Station; additionally, one between 6 and 7 a.m. and one between 7 and 8 p.m. were added for the same section with the schedule revision of March 15, 2008.
During the day, the special rapid train bound for Omi-Imazu Station and Tsuruga Station stops at Otsukyo Station and variously connects with the local train in order for passengers to change trains. The special rapid train bound for Kyoto and Osaka variously connects with local trains at Katata Station. However, only a few local trains variously connect with the special rapid train because a few special rapid trains are operated on the Kosei Line.
Since the opening of the Kosei Line, a special train has existed for the transportation of passengers bound for Lake Biwa and the Hira mountain range. Initially, the special train ran to extend the regular special rapid service to Katata Station to Omi-Imazu Station or to extend the rapid train between Aboshi Station and Osaka Station to the Kosei Line. Some special trains adopt cars (Series 155) used for school trips, which are unused during the summer and winter seasons, and the cars of Miyahara Ward have received seismic reinforcement and hardy construction during the season.
Later, as the regular trains operated more frequently, the number of special trains decreased; however, the special rapid train, which temporarily stops at Shiga Station, is called 'Kosei Leisure Go' in order to distinguish it from the regular special rapid train. As the special rapid service was extended to Tsuruga Station, trains (comprised of four cars) have been regularly operated as special trains for the increased numbers of passengers since the fall of 2006, and especially for the transportation of passengers who use Makino Station (the nearest stop) to enjoy the blossoms at Kaizu-Osaki, the train bound for Tsuruga Station to be divided is operated as a special train prior to the regular train. In the tourist season, a train traveling around Lake Biwa is frequently operated as a train reserved for groups.
Connection to the Tokaido Line at Kyoto Station
The Kosei Line would use the platforms of the Tokaido Line when the Kosei Line was opened, but Platform 3 was given to the Kosei Line after the improvement work within Kyoto Station; many trains currently arrive at and depart from Platform 3. Some trains arriving at Kyoto Station stop at Platforms 5 to 7 and are then transferred to the Mukomachi Operation Center (currently the Kyoto Integrated Operation Center).
Due to this form of operation, passengers can change trains on the same platform: from Osaka it's convenient to change at Kyoto Station for the train to the Kosei Line, and from the Kosei Line it's convenient to change at Yamashina Station for the train to Osaka.
With the schedule revision of March 2002, the train to the Kosei Line was connected to the special rapid train from Osaka; however, a slight delay in the special rapid train greatly affected the schedule of the Kosei Line, and therefore the schedule was changed in March 2006 (the introduction of a so-called uncongested schedule) in order to have the train to the Kosei Line leave before the arrival of the special rapid train, except for some trains at night.
Coupling and decoupling for special rapid trains
With the extension of the special rapid service to Tsuruga Station in October 2006, the platforms at Omi-Shiotsu and Shin-Hikida Stations were elevated and the middle track (Platform 4) at Tsuruga Station was shortened to an effective length equal to four cars, whereby the coupling and decoupling of cars has been carried out at Omi-Imazu Station (some trains are managed at Kyoto Station). Accordingly, a guide signal was newly installed on track 3 (Platform 2) at Omi-Imazu Station. Therefore, a stop of approximately ten minutes is required, during which time the Limited Express Raicho (train) passes the special rapid train. It is rare that the limited express train passes the special rapid train, except for one example in which the Limited Express 'Hakuto (train)' passes the special rapid train while the special rapid train is being decoupled at Himeji Station (there is an example that the limited express train passes the special rapid train on the Biwako Line, but this occurs within a quadruple track and the special rapid train doesn't wait for the limited express to pass). Because of the time required for stopping for this division and connection, the travel time of the special rapid train between Osaka and Tsuruga stations is ten minutes longer than the initial estimate of 1 hour and 50 minutes (in particular, the travel time of special rapid trains between Kyoto Station and Omi-Nakasho, Makino and Nagahara stations is substantially equal to that of local trains between Kyoto and Nagahara stations).
Likewise, about ten minutes are required for the special rapid train bound for Omi-Shiotsu and Tsuruga stations via Maibara Station in order to stop for the division and connection.
Signs of the special rapid trains and descriptions on the timetable
Even in the section in which the special rapid train stops at every station to the north of Omi-Maiko Station and Hikone Station, the train runs with the sign 'Special Rapid,' while the timetable includes descriptions of 'Special Rapid.'
In contrast to the rapid train in the Keihanshin area, which becomes 'Local' at Akashi Station and the stations to the west of Akashi Station and Takatsuki Station (Kyoto Station in some time periods) and the stations to the east of Takatsuki Station, the special rapid train remains 'Special Rapid' even when it stops at every station (including Himeji Station and the stations to the west of Himeji Station). This is because the special rapid is kind of branded, and thus it is important for local governments that 'special rapid trains pass' the stations even if they actually stop at every station.
Construction for DC electrification
During the construction of the Kosei Line, Yamashina Station was DC-electrified and Omi-Shiotsu Station was AC-electrified. Accordingly, AC/DC switching section was installed between Nagahara Station and Omi-Shiotsu Station. Because of this, electric cars going through to the Hokuriku area on the Kosei Line were limited to cars capable of switching AC and DC thereon, namely AC/DC electric cars such as JNR/JR Limited Express Series 485 and JNR/JR Electric Locomotive Type EF81for AC/DC electric cars. An expensive general AC/DC electric car wasn't introduced as a local train running between the Kosei and Hokuriku areas in which large demand couldn't be expected, and thus a diesel train was operated as a local train between the electrified section: between Omi-Imazu Station and Tsuruga Station before September 1991 (after that, an AC/DC electric car was operated). The line between Yamashina Station and Nagahara Station was DC-electrified, to which a DC electric car entered from Kyoto.
Meanwhile, the Hokuriku Line was AC-electrified and operated with a few local trains; passengers were required to change trains at Maibara Station in order to transfer from the Kohoku area, the northern coastal area of Lake Biwa, to Otsu Station or the Keihanshin area. In 1986, in the era of the JNR, the Shiga Prefecture and local governments established the 'Alliance for Promoting DC Electrification of the Hokuriku Main Line' at the commerce and industry associations of local cities along the line, and demanded that JNR/JR change the electrification system of the Hokuriku Line for the improvement of convenience; subsequently, in May 1990 the cities of the Kosei area were additionally involved to newly establish the 'Alliance for Promoting the Lake Biwa Loop Line' in order to work on the JR.
As a result, in the next year the construction for DC electrification was carried out between Maibara Station and Nagahama Station. Originally, the AC/DC section was between Sakata and Tamura stations, which was transferred to operate between the Nagahama and Torahime stations. The construction cost of about 0.7 billion yen was funded by the local governments, including Shiga Prefecture and Nagahama City.
After the schedule revision of September 1991, and upon the completion of construction, the special rapid train came to run through to Nagahama Station from the Keihanshin area, thus producing economic effects such as an increase in the general population and numbers of tourists. The entry of the special rapid to Nagahama Station brought the area within commuting distance to the Keihanshin area, while the utilization of local resources for tourism, such as Kurokabe Square, resulted in the increase in the number of tourists visiting Nagahama; the construction for DC electrification won the attention of the whole country as a trigger for regional development.
The local governments of the Kohoku area also began to take action, encouraged by the success of Nagahama. Likewise, in the Kohoku area, where the line was AC-electrified and thus operated with only a few trains, and a through-train to Maibara Station and stations to the west of Maibara Station didn't exist, 'the special rapid train' gathered momentum; since the transfer among the Kosei and Kohoku areas was inconvenient because of the existence of the AC/DC section and a few through-trains being operated, the construction for the DC electrification was the important challenge for the local governments so as to overcome these problems.
In 1995, the local governments began to reserve fund for construction every year and worked on maintenance around the stations or building of guide signs of sightseeing facilities, thereby promoting the 'Lake Biwa Loop Line Plan.'
In reference to the success of Nagahama, Tsuruga City also planned to increase the number of tourists by a through special rapid train and began to work on the achievement of DC electrification with Fukui Prefecture in order to increase the number of through-trains from the Keihanshin area.
As part of railway construction, the following purposes were set:
To have a through train to the Kohoku area;
To make it convenient for passengers to move between the Kosei and Kohoku areas by using trains; and
To have the special rapid train go through to Tsuruga Station from the Keihanshin area;
Thereby to begin the construction for the DC electrification of the Kosei and Hokuriku lines. The construction cost has been divided among Shiga Prefecture (the prefecture and the local governments) and Fukui Prefecture (the prefecture and Tsuruga City), since the construction was requested by the locals.
(The construction cost is 16.1 billion yen, of which Shiga Prefecture bears 7.5 billion yen and Fukui Prefecture bears 6.8 billion yen, while JR West bears 1.8 billion yen for the manufacture of new cars.)
In the construction for DC electrification, the dead sections between Nagahama Station and Torahime Station and between Nagahara Station and Omi-Shiotsu Station were transferred to the section between Tsuruga Station and Minami-Imajo Station (between Tsuruga Station and Hokuriku tunnel, Tsuruga exit), and the section on the Hokuriku Line, between Nagahama Station and Tsuruga Station and the section on the Kosei Line between Nagahara Station and Omi-Shiotsu Station were DC electrified, all of which were completed on September 24, 2006.
With the schedule revision of October 21, 2006, the special rapid train comprised of JR (West) Suburban Train Series 223, DC electric train operation came to Tsuruga Station, while the connection between the Kosei Line and the Hokuriku Line bound for Nagahama Station was improved. The number of special rapid trains was increased to 25 per day, running mainly during the day (17 via Kosei Line and 8 via Biwako Line (Hokuriku Main Line)) to Tsuruga Station by extending the operation from Omi-Imazu Station and Nagahama Station, while 18 special rapid trains came to enter Omi-Shiotsu Station per day (via the Biwako Line and Hokuriku Main Line). At Omi-Shiotsu Station, it became possible to change trains on the same platform: during the day from the train bound for Tsuruga Station via Kosei Line, changing for the train departing from Omi-Shiotsu Station to Himeji Station via Maibara Station; and from the train to Omi-Shiotsu Station via Maibara, changing for the train departing from Tsuruga to Himeji via the Kosei Line, thereby improving the connection between the Kohoku and Kosei areas. There is only one special rapid train to Omi-Shiotsu Station via Maibara Station per day, which connects to the special rapid train bound for Tsuruga Station via the Kosei Line at Omi-Shiotsu Station, and the train to Omi-Shiotsu Station subsequently becomes a train bound for Omi-Imazu Station with passengers on board.
Incidentally, the standard travel time of the special rapid train entering the Hokuriku Line is approximately 95 minutes between Tsuruga Station and Kyoto Station via the Kosei Line, approximately 125 minutes between Tsuruga Station and Osaka Station, approximately 145 minutes between Tsuruga Station and Sannomiya Station, and approximately 185-190 minutes between Tsuruga Station and Himeji Station. The travel time is approximately 15 minutes longer in the case where the train passes Maibara Station. Originally there was little local flow between the Kosei area and Tsuruga, whereas there is some local flow between the Kohoku area and Tsuruga; therefore, the special rapid trains departing from and arriving at Tsuruga Station are operated via the Kosei Line during the day and, except for the daytime, the special rapid trains are operated via Maibara Station. Therefore, the travel time during the morning and evening may be shorter, when the train is operated via Maibara Station. Accordingly, the Tsuruga City is demanding that the JR West increase the number of trains and make an exception for boarding with commuter tickets (see below), but it's not certain whether the demand will be accepted.
In the case of travel between Yamashina Station and Omi-Shiotsu Station using a standard ticket, an exception of a specific route section is applied, where a fare based on operating kilometers via the Kosei Line also covers that via Maibara Station; however, a specific route section isn't applied to a commuter ticket and consequently passengers can't use commuter tickets via the Kosei Line (which is cheaper) for travel via Maibara Station. With the current schedule, there is still only one special rapid train via Kosei Line departing from and arriving at Tsuruga Station in the morning and evening; thus there is a demand for an optional boarding exception for a commuter ticket.
Construction for installation of windbreak fences
As described above, speed limitations are increasingly applied, as are the regulations of operation due to strong winds; accordingly, in the fiscal 2006 there were 28 days in which the operation was regulated. As a result, the JR West installed windbreak fences along the mountains (on the west side), the line between Hira Station and Omi-Maiko Station in October 2007, and thereby announced that JR West would regulate the operation with winds of 30 meters per second up from the former 25 meters per second. Thus it is estimated that the annual frequency of operation cancellation has been reduced by half. The construction began in early April 2008 (with JR bearing the entire construction cost). The construction was performed by DAITETSU KOGYO CO., LTD.
JR (West)/Hokuetsu Express' Limited Express Series 681 and 683 (Limited Express 'Raicho')
JNR/JR Limited Express Series 485 (L-Limited Express 'Raicho')
JNR/JR Passenger Car Series 24 (Limited Express 'Twilight Express' and Limited Express 'Nihonkai')
JR (West) Suburban Train Series 223
The JR (West) Suburban Train Series 223 is used for all rapid and special rapid trains comprised of eight or twelve cars on the Kosei Line, as well as for local trains comprised of four to eight cars on part of the line.
Yamashina Station - Nagahara Station
JNR/JR Suburban Train Series 113
When the Kosei Line was opened, there appeared the model numbers 700's of the JNR/JR Suburban Train Series 113, which have measures such as semiautomatic doors for cool regions; these have been the major cars operated on the Kosei Line and are operated comprised of four to eight cars along with the cars of the model numbers 2700's, which appeared for the electrification of the Kusatsu Line. The JNR/JR Suburban Train Series 113 comprised of six cars existed for a period of time, but it's no longer in operation.
JNR/JR Suburban Train Series 117
The measures such as semiautomatic doors for cool regions were primarily intended in view of operation on the Kosei Line. The JNR/JR Suburban Train Series 117 is often comprised of the original cars and seat-modified cars, and is operated with six or eight cars.
JR (West) Commuter Train Series 207
The JR (West) Commuter Train Series 207 is operated for trains departing from Katata Station early in the morning and bound for Omi-Maiko Station during the night on weekdays. The JR (West) Commuter Train Series 207 of production cars would be called for at Omi-Imazu Station from the beginning, but they were abandoned with the revision of March 18, 2006. Incidentally, the F1 car, a test-production car, is commonly operated with JR (West) Commuter Train Series 321 as described below.
JR (West) Commuter Train Series 321
The JR (West) Commuter Train Series 321 enters Katata Station once before noon on weekdays. With the revision of March 18, 2006, the JR (West) Commuter Train Series 321 was used for trains bound for Omi-Maiko Station during the night but was soon replaced with the JR (West) Commuter Train Series 207 with the revision of March 15, 2008.
JR (West) Suburban Train Series 221
The operation of the JR (West) Suburban Train Series 221 belonging to the Aboshi yard began as the special rapid trains on the Kosei Line when the series first appeared; moreover, it was subsequently used in part of the operation within the line but was later abandoned with the revision of October 2006. Since March 15, 2008, the JR (West) Suburban Train Series 221 has been operated again on the Kosei Line with cars belonging to the Kyoto Integrated Operation Center.
Omi-Imazu Station - Omi-Shiotsu Station
JR (West) Suburban Train Series 521
The JR (West) Suburban Train Series 521 was introduced when the Hokuriku Main Line and the Kosei Line were DC-electrified, all of which are comprised of two cars. All the local trains stopping at Nagahara Station and stations to the north of Nagahara Station are of the JR (West) Suburban Train Series 223 and JR (West) Suburban Train Series 521.
Before introducing the JR (West) Commuter Train Series 207, JNR/JR Commuter Train Series 201 and JNR/JR Commuter Train Series 205 would also enter the Kosei Line, but eventually they were replaced with the JR (West) Commuter Train Series 207 and today are not regularly used.
Because of their unique appearance, the JNR/JR Suburban Train Series 419 and JNR/JR Suburban Train Series 715, which were called 'bread trains,' and JNR/JR Suburban Trains Series 457, which were converted from the rapid train, were used at Omi-Imazu Station and stations to the north from 1991, but they disappeared from regular operation on the Kosei Line after Tsuruga Station was DC-electrified due to the revision.
The Kosei Line was established as a short circuit track connecting Osaka and the Hokuriku area. Initially, the line between Hamaotsu Station and Omi-Imazu Station was operated by the Kojak (Kojaku) railway by local interests; the matter of the Kojak (Kojaku) railway became a problem when planning the Kosei Line, because a track in planning was substantially parallel with this line. The Kojak (Kojaku) railway eventually left the business, and its track was purchased and converted. However, the actual purpose was to purchase the competing track in order to bail out; the actual conversion rate was low, and there are many sections in which the abandoned track can be seen from the windows of the train. After the Kojak (Kojaku) railway left the railway business in October 1969, the company name was changed to Kojak Bus Co., Ltd.
April 11, 1922: The line between Hamaotsu Station and Miyake Station (currently the Obama Line's Kaminaka Station) was incorporated into a JNR excepted line.
May 31, 1962: The line between Hamaotsu Station and Shiotsu Station became a JNR investigated line.
June 25, 1964: The line between Yamashina Station and Kutsukake Station became a JNR constructed line.
December 28, 1966: The lines between Yamashina Station and (temporarily called) Kitaotsu Station (currently Otsukyo Station) and between Omi-Imazu Station and Omi-Shiotsu Station were primarily approved.
January 12, 1967: The groundbreaking ceremony of the Kosei Line was held at Ojiyama General Sports Park/Ojiyama Sports Park.
November 1, 1969: The line of the Kojak (Kojaku) railway was abandoned.
July 20, 1974: The line between Yamashina Station and Omi-Shiotsu Station (74.1 km) was opened. At the same time, the JNR/JR Suburban Train Series 113 began operating. The special rapid train began entering the line between Yamashina Station and Omi-Imazu Station.
March 10, 1975: The limited express and express 'Raicho (train)' that run between Osaka and Hokuriku and Tohoku areas began passing the Kosei Line.
April 1, 1987: Japan National Railways was split and privatized as the JR Group, including the West Japan Railway Company, which succeeded the Kosei Line. The Japan Freight Railway Company became a type II railway business operator for every line.
December 4, 1988: Ono Station was opened.
March 18, 1993: The JR (West) Commuter Train Series 207 was introduced.
September 4, 1994: Eizan Station was renamed as Hieizan-Sakamoto Station.
September 24, 2006: The line between Nagahara Station and Omi-Shiotsu Station was changed from AC electrification to DC electrification.
October 21, 2006: The operation of the special rapid train was extended to Tsuruga Station, thereby operating throughout the Kosei Line.
March 15, 2008: Nishiotsu Station was renamed as Otsukyo Station and Ogoto Station was renamed as Ogotoonsen Station.
List of stations
Among intermediate stations, the only ones under direct control are the Otsukyo, Katata and Omi-Imazu stations. All the stations are subcontracted by JR West Kotsu Service, except that Omi-Nakasho Station remains unmanned throughout the day (Nagahara Station was also unmanned before April 2000).