 Viewed fromKannami Station. | |
| Overview | |
|---|---|
| Line | Tōkaidō Main Line |
| Location | Shizuoka Prefecture,Japan |
| Coordinates | 35°06′16″N139°01′00″E / 35.10444°N 139.01667°E /35.10444; 139.01667 |
| Operation | |
| Opened | 1934 |
| Operator | JR Central |
| Character | passenger/freight |
| Technical | |
| Line length | 7,804 meters |
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Tanna Tunnel (丹那トンネル,Tanna-tonneru) is arailroadtunnel inShizuoka Prefecture,Japan operated byJR Central’sTōkaidō Main Line. This 7.8 km long tunnel shortened the trunk route betweenTokyo andKobe by omitting a detour round the mountains betweenAtami andNumazu.[1]
The initial routing of the Tōkaidō Main Line railway, connecting Tokyo withOsaka, avoided theHakone mountains between Shizuoka andKanagawa Prefectures by taking a long detour north toGotemba and then south to Numazu. This route is now known as theGotemba Line, and it follows the same path as theTōmei Expressway to this day.
Recognizing that the Gotemba loop created a significant bottleneck in the rail system, the JapaneseRailroad Ministry issued a contract in 1918 to theKajima Corporation to build a tunnel through the Hakone mountains. The project was promoted as a majorpublic works initiative intended to help boost Japan’s economy following the post-World War Ieconomic recession.
However, the construction of the 7,804-meter tunnel proved extremely challenging due to numerous unforeseen issues with the localgeology and contemporary tunneling technology. The Hakone mountain range is an active volcanic zone, containing a number offaults and frequently experiencingearthquakes. In addition, workers faced problems with significant water seepage, soft rock formations, andhot spring water vents. On April 1, 1920, a large section of the tunnel collapsed from the Atami side, trapping 42 workers. Despite heroic efforts to rescue them, only 17 workers were saved a week later. The tunnel was also damaged during theGreat Kantō earthquake, although no fatalities occurred. Another collapse took place on February 26, 1930, during an earthquake, resulting in the deaths of five more workers. The project took far longer and cost much more than originally anticipated, with a total of 67 workers losing their lives during construction.
The two ends of the tunnel were joined on June 19, 1933, and the Tanna Tunnel opened to rail traffic on March 10, 1934. At the time of its completion, it was Japan’s second-longest tunnel, only surpassed by theShimizu Tunnel once it was finished.
The story of the construction of the Tanna Tunnel was the subject of a stage play byHideji Hōjō in 1942.
The Tanna Tunnel remains in operation on the Tōkaidō Main Line to this day. Traffic on theTōkaidō Shinkansen uses the parallelShin-Tanna Tunnel (7,950m)[1] completed in 1963.
