Qualla: Bentenyama Tunnel

Bentenyama Tunnel: Introduction

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Dr.yellow, CC BY-SA 4.0. Before the world's first bullet train could carry a single passenger, it had to prove itself underground. The Bentenyama Tunnel, a 1.316-kilometer bore through the Oiso hills of Kanagawa Prefecture, was completed in 1962 -- two full years before the Tokaido Shinkansen opened for service. It sat within the Kamonomiya test section, a 32-kilometer stretch between Odawara and Ayase where prototype trains shattered speed records and engineers ironed out the physics of moving people at velocities no railway had ever sustained. Today, Shinkansen trains flash through Bentenyama in seconds. But this tunnel was one of the places where the bullet train was born.

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Image: Dr.yellow | CC BY-SA 4.0

Bentenyama Tunnel: The Proving Ground

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Original uploader was David.Monniaux at en.wikipedia, CC BY-SA 3.0. The Kamonomiya model track, as engineers called it, opened in June 1962 as the critical test bed for Shinkansen technology. Over two years, prototype trains logged a remarkable 250,000 kilometers on this section alone. On October 27, 1962, a test consist designated 'set B' reache...

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Image: Original uploader was David.Monniaux at en.wikipedia | CC BY-SA 3.0

Bentenyama Tunnel: Layers of Sand and Stone

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Dr.yellow, CC BY-SA 4.0. The geology beneath Bentenyama tells its own story. The tunnel cuts through the southwestern edge of the Oiso hill land, a region characterized by diluvium-tertiary formations -- ancient layers of compacted soil dating back tens of thousands of years. Alongside the tunnel's path,...

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Image: Dr.yellow | CC BY-SA 4.0

Bentenyama Tunnel: A Dream Decades in the Making

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Dr.yellow, CC BY-SA 4.0. Japan's bullet train did not spring from nothing in 1959, when construction formally began. The idea traced back to the Dangan Ressha project of 1939, a wartime plan to build a high-speed wide-gauge railway along the Tokaido corridor. The government acquired land and began boring...

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Image: Dr.yellow | CC BY-SA 4.0

Bentenyama Tunnel: Seconds of Passage, Decades of Service

Mon, 16 Feb 2026 00:00:00 GMT

Photo credit Dr.yellow, CC BY-SA 4.0. When the Tokaido Shinkansen opened on October 1, 1964, nine days before the Tokyo Olympics, it connected Tokyo and Osaka in four hours. The Hikari express and the all-stops Kodama began their runs along a route that remains one of the busiest rail corridors on Earth. The Bentenya...

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Image: Dr.yellow | CC BY-SA 4.0