| Locale: | Shizuoka Prefecture |
| Itō Line | |
| Type: | Heavy rail |
| Stations: | 6 |
| Electrification: | (Overhead line) |
| Maxincline: | 2.5% |
| Trainprotection: | ATS-P |
The is a railway line owned by the East Japan Railway Company (JR East) which connects Atami and Itō Stations, along the east coast of Izu Peninsula in Shizuoka Prefecture, Japan. From Itō, the line continues south to Shimoda under the privately owned and operated Izu Kyūkō Line.
| Station No. | Name | Japanese | Distance from Atami (km) | Transfers | Location | |
|---|---|---|---|---|---|---|
| (Through service for,, via Tokaido Main Line, Ueno-Tokyo Line, Utsunomiya Line and Takasaki Line) | ||||||
| 熱海 | 0 | Tokaido Shinkansen Tokaido Main Line | Atami | Shizuoka | ||
| 来宮 | 1.2 | |||||
| 伊豆多賀 | 6.0 | |||||
| 網代 | 8.7 | |||||
| 宇佐美 | 13.0 | Itō | ||||
| 伊東 | 16.9 | Izukyu Izu Kyūkō Line (through service) | ||||
| (Through service for via Izu Kyūkō Line) | ||||||
Most of the local trains are only run between Atami Station and Izukyū Shimoda station via Izu Kyūkō Line.
A few local trains with Green Cars departing from Itō Station enter the Tokaido Main Line, with most of them entering the Ueno-Tokyo Line, and the farthest terminals are Utsunomiya Station or Kagohara Station. As such, Itō Station is the most southern terminal of the Ueno-Tokyo Line.
Initial plans called for the Japanese National Railways (JNR) to build a spur line linking Atami on the Tokaido Main Line with Shimoda. However, funding was limited in the 1930s due to a combination of a tight fiscal policy under Prime Minister Osachi Hamaguchi during the Great Depression, and a number of technical issues. The projected route of the Itō line along the mountainous east coast of the Izu Peninsula required numerous tunnels and bridges. Workers digging a tunnel near encountered problems with underground hot springs, similar to that experienced in the construction of the Tanna Tunnel, which had recently been completed years later than originally projected and far over budget.
On March 30, 1935, the initial 8.7 km section of the Itō Line linking Atami with was opened. The second (8.3 km) section from Ajiro to was opened on December 15, 1938. Both sections were electrified at 1,500 V DC when opened. Further work was delayed, and then canceled due to the outbreak of World War II.
CTC signalling was commissioned in 1958, and the Atami to Kinomiya section was duplicated in 1968. The entire line was originally designed to be built as double track, and earthworks were undertaken on this basis, including tunneling, but to date only the first 1.2 km of the line has been duplicated.
Construction south of Itō resumed in 1961, when the private-sector Tokyu Corporation acquired the rights to complete the line to Shimoda and established the Izukyu Corporation to manage construction and operations of this section.