Sōtetsu Main Line

The Sōtetsu Main Line (相鉄本線) is a railway line in Kanagawa Prefecture, Japan, operated by the private railway operator Sagami Railway (Sotetsu). It connects Yokohama and Ebina.

Services
Services on the Main Line are divided into four categories. Some trains travel along the Izumino Line west of Futamata-gawa to Shōnandai.
 * Local (各停) - services stop at all stations. They do not travel from end to end; services are split at Futamata-gawa, with trains running between Yokohama and Futamata-gawa and between Futamata-gawa and either Ebina or Shōnandai.
 * Rapid (快速) - services stop between Yokohama and Futamata-gawa at Hoshikawa, Nishiya and Tsurugamine, and at all stations from Futamata-gawa to either Ebina or Shōnandai.


 * Commuter Express (通勤急行 or 通急) - services stop between Yokohama and Futamata-gawa at Nishiya and Tsurugamine, and at all stations from Futamata-gawa to either Ebina or Shōnandai.
 * Commuter Limited Express (通勤特急 or 通特) services between Shōnandai and Shin-yokohama and continue through running on either the Tokyu Toyoko Line or Meguro Line and their subsequent through services.
 * Limited Express (特急) services stop between Yokohama and Ebina at Nishiya, Futamata-gawa and Yamato.

Stations

 * All stations are located in Kanagawa Prefecture.
 * Local trains stop at all stations; For all other train types, trains stop at stations marked ●, and pass stations marked | and ↑.
 * Commuter Limited Express services stop at stations marked ▲.

Current
Sotetsu
 * 8000 series (10 car sets, since December 1990)
 * 9000 series (10 car sets, since January 1993)
 * 10000 series (8/10 car sets, since February 2002)
 * 11000 series (10 car sets, since June 2009)
 * 12000 series (10 car sets, since 20 April 2019)
 * 20000/21000 series (10/8 car sets, respectively, since 11 February 2018)

JR East
 * E233-7000 series (10 car sets, since 30 November 2019)

Tokyu
 * Tokyu 3000 series (8 car sets, since 18 March 2023)
 * Tokyu 5050-4000 series (10 car sets, since 18 March 2023)
 * Tokyu 5080 series (8 car sets, since 18 March 2023)
 * Tokyu 3020 series (8 car sets, since 26 September 2023)

Former

 * 5000 series (from 1955 until 2009)
 * 6000 series (from 1961 until 2005)
 * 7000 series (from 1975 until 2020)

Non-revenue-earning stock

 * 2000 series
 * ED10 electric locomotives

History
The line opened on 12 May 1926 as the steam-operated Jinchu Railway (神中鉄道) between Futamata-gawa and Atsugi (on the present-day Sagami Line). The line was extended from Futamata-gawa to Yokohama in December 1933, and from the former station at Sagami-Kokubu (相模国分) (now closed) in November 1941.

The line became the Sagami Railway Jinchu Line (相模鉄道神中線) from 1 April 1943. However, when the line was commissioned to Tōkyū due to the financial difficulties of the Sagami Railway, it was renamed as the "Tōkyū Atsugi Line" (東急厚木線) until the end of the commission in 1947.

Work to electrify the line commenced in June 1942, with the entire line between Yokohama and Ebina electrified by 20 September 1944.

Work to double-track the line commenced in January 1957 between Yokohama and Nishi-Yokohama. The entire line was double-tracked by March 1974.

The first air-conditioned trains (4-car 6000 series EMUs) were introduced on the line on 3 July 1971.

10-car trains started operating on the line from 6 April 1981.

Station ticket barriers were modified to allow use of the Passnet magnetic farecard from 1 October 2000.

There was a short spur line which branched from Sagamino Station to the Naval Air Facility Atsugi air base. While the track remains in place up to the fence of the base, the line is no longer in use.

In order to improve safety and efficiency, a 2.8 km section around Tsurugamine Station is being transitioned to an underground structure. The underground track section and new station building is expected to be completed in 2034.

On a side note, what is known today as the Sagami Line had been constructed and owned by Sōtetsu, until 1944 when it was acquired by the government during World War II. After the war, the government and Sōtetsu never reached any agreement to return the line to Sōtetsu, and today it is run by JR East.

March 2023 timetable revision
The Sōtetsu Shin-yokohama Line connects Nishiya to Hazawa Yokohama-Kokudai, Shin-Yokohama and further to the Tōkyū Shin-yokohama Line. Through service to the Saikyō Line began on 30 November 2019 while services to the Tōkyū Shin-Yokohama Line began on 18 March 2023.

With the opening of this new line, Limited Express and Rapid services make a stop at Nishiya, which facilitates transfer between services to central Yokohama and the Tokyo Metropolis.

In addition, two new service types will be implemented. They are the Commuter Limited Express (通勤特急) and Commuter Express (通勤急行) services, which both operate through services from / to the Izumino Line. The former service will replace the current Express on the Izumino Line, and will make additional stops at Nishiya and Tsurugamine. The latter service is a brand new service, making stops at all stations west of Nishiya.