A Victorian Truss Carried into a Mountain Gorge
The Hakone Tozan Railway Hayakawa Bridge (箱根登山鉄道早川橋梁, Hakone Tozan Tetsudō Hayakawa Kyōryō), universally known as the Deyama Iron Bridge (出山の鉄橋, Deyama no Tekkyō), is a single-span railway truss over the Hayakawa river in Hakone Town, Ashigarashimo District, Kanagawa Prefecture, fabricated in England in 1888, re-erected at its present site in 1917, and entered on Japan's national register of Tangible Cultural Properties on 7 June 1999. It is generally counted as the oldest railway bridge still carrying trains in Japan.
The structure is a pin-connected double Warren truss of British type, a 200-foot girder with a span length of 61.0 metres. It sits 43 metres above the riverbed, between Tōnosawa Station and the Deyama signal box on the line that climbs from Hakone-Yumoto to Gōra.
The truss did not begin its life here. It was made in 1888 by the Patent Shaft & Axletree Company of Wednesbury in the English Midlands, to a design by Charles Assheton Whately Pownall, the British engineer then serving Japan's government railways, and it formed one span of the Tenryūgawa bridge on the Tōkaidō Main Line, the trunk route that reached full opening in 1889. The Agency for Cultural Affairs entry records the material as a mixed wrought-iron and steel girder of British manufacture, transmitted as such rather than fully documented, and notes that the structure retains its original form to an unusual degree.
That material is the point of its rarity. The 1880s sat exactly on the hinge between wrought iron and steel in bridge building, and girders combining the two belong to a narrow window. This is described as the only surviving mixed-material 200-foot girder in the country.
Why a Second-Hand Bridge, and Why the Governor Objected
The Odawara Electric Railway had intended to build a new arched truss for the crossing. The First World War ended that plan by cutting off the imported material the company had counted on. So it applied to the Railway Board for a cast-off, and received one span of the Tenryūgawa bridge, then thirty years old.
The Governor of Kanagawa was not pleased. Immediately before work began he objected that hanging a used bridge across the Hayakawa, at the very gateway to Hakone, would spoil the scenery. Construction was allowed to proceed on the condition that the bridge would be replaced later.
It never was. The proposal was not raised again, and the governor's temporary compromise has now carried trains for more than a century. In 1991 the bridge was chosen for Kanagawa's Hundred Bridges, in 1999 it was placed on the national register under the criterion of being difficult to reproduce, and it has since been recognised as a Modernisation Industrial Heritage site.
Building it was the harder part of the story. Work started in 1915. Erecting a 61-metre truss across a gorge 43 metres deep and 60 metres wide required a timber falsework of extraordinary scale, and the log count is often given as around ten thousand. Almost no records of the operation survive beyond a single construction photograph, so the method remains partly guesswork. The bridge was finished on 31 May 1917. Dismantling of the falsework was to begin the following day. That night a storm put the Hayakawa in flood and washed the entire scaffold away. The bridge itself was untouched.
It has kept that habit. When the Great Kantō Earthquake struck on 1 September 1923 and wrecked much of the railway, the Hayakawa bridge came through with slight damage to an abutment. Before the earthquake, National Route 1 crossed the line on the level at the Deyama end; the road was afterwards lowered to pass beneath.
How to See It, and What to Notice
The double Warren form, also called a lattice truss, sets its diagonal members in an X pattern. The diagonals cross at their midpoints and are pinned to one another there, which resists buckling under compression and allows slimmer members than a plain Warren truss would need. Seen from below, the effect is a fine crosshatch rather than a heavy frame, which is a large part of why a piece of Victorian iron looks at home against a wooded gorge.
Look at the height of the truss and you find a nice piece of engineering awkwardness. The Tōkaidō Main Line was not electrified in 1888, so the truss stands only 5,283 millimetres tall, low for a bridge that now carries electric trains. The line uses rigid overhead conductor rails here to keep the contact wire as low as possible, and even so the trains cross with their pantographs pressed down close to folded. Watch a train pass and the squeeze is visible.
The most straightforward way to experience the bridge is to ride across it. Take the Hakone Tozan Line from Hakone-Yumoto toward Gōra and the crossing comes shortly after Tōnosawa. The line itself is a spectacle: gradients reaching 80 per mille, curves down to a 30-metre radius, and three switchbacks where the driver and conductor change ends. During the autumn colour season the railway halts trains on the bridge for a few seconds so passengers can look down into the gorge. The same service has been offered for decades and remains one of the small pleasures of the line.
To photograph the bridge you need to be off the train. A bus from Hakone-Yumoto Station along National Route 1 stops at Deyama, and the bridge stands almost directly in front of the stop; this is the classic viewpoint and requires no walking to speak of. Access onto the bridge is impossible: it is live railway with no walkway, and trains run frequently.
There is no admission charge, no gate and no opening hours, since the bridge is simply part of an operating railway. A Hakone Freepass covers the Tozan Line along with the cable car, ropeway and lake boats, and makes the bridge one stop in a longer circuit rather than a destination in itself. Hakone-Yumoto's hot spring inns lie a few minutes back down the valley, and Tōnosawa, the older and quieter of the two spa clusters, sits immediately below the bridge.
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Q&A
- Where exactly is the Hakone Tozan Railway Hayakawa Bridge and how do I see it?
- It crosses the Hayakawa river in Hakone Town between Tōnosawa Station and the Deyama signal box. You can ride over it on any Hakone Tozan Line train heading from Hakone-Yumoto toward Gōra. To photograph it, take a bus from Hakone-Yumoto Station along National Route 1 and get off at the Deyama stop, where the bridge stands directly ahead. Walking onto the bridge is not possible.
- Is there an admission fee to see the Hakone Tozan Railway Hayakawa Bridge?
- No. It is part of a working railway, so there is no gate, no ticket and no opening hours. Riding across it costs the ordinary Hakone Tozan Line fare, and a Hakone Freepass covers the line along with the cable car, ropeway and lake boats.
- Why is the Hakone Tozan Railway Hayakawa Bridge considered important?
- Because of what it is made of and where it came from. Fabricated in England in 1888 to a design by Charles Assheton Whately Pownall, it served as one span of the Tenryūgawa bridge on the Tōkaidō Main Line before being moved here in 1917. It is described as the only surviving mixed wrought-iron and steel 200-foot girder in Japan and is generally counted as the oldest railway bridge still carrying trains in the country. Registration came on 7 June 1999 under the criterion of being difficult to reproduce.
- Do trains stop on the Hakone Tozan Railway Hayakawa Bridge?
- During the autumn foliage season the railway pauses trains on the bridge for a few seconds so passengers can look down the 43-metre drop into the gorge. Outside that season trains cross without stopping. Dates follow the colour, so check the railway's announcements if timing matters to you.
- Why do the trains crossing the Hakone Tozan Railway Hayakawa Bridge look so cramped?
- The truss was built in 1888 for a line with no overhead wires, so it is only 5,283 millimetres tall. To fit electric traction through it the railway uses rigid overhead conductor rails rather than a suspended contact wire, and even then trains pass with their pantographs compressed close to the folded position.
Basic Information
| Name | Hakone Tozan Railway Hayakawa Bridge (箱根登山鉄道早川橋梁); commonly the Deyama Iron Bridge (出山の鉄橋) |
|---|---|
| Location | Tōnosawa Aza Daigatake 192-7 to Ōhiradai Aza Fukitsukemichishita 10-3, Hakone Town, Ashigarashimo District, Kanagawa Prefecture |
| Designation | Registered Tangible Cultural Property (Structure), register no. 14-0026; also recognised as Modernisation Industrial Heritage |
| Year Designated | 1999 (registered 7 June 1999, gazetted 19 July 1999) |
| Quantity | 1 structure |
| Dimensions | Pin-connected double Warren truss in iron and steel; span length 61.0 m; truss height 5,283 mm; 43 m above the riverbed. Fabricated 1888, re-erected 1917 |
| Owner | Odakyū Hakone Co., Ltd. |
| Public Access | In daily railway service. Free to view from the Deyama bus stop; crossing by train at ordinary fares. No pedestrian access to the bridge deck |
References
- National Database of Registered and Designated Cultural Properties, Agency for Cultural Affairs
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00001105
- Cultural Heritage Online, National Institutes for Cultural Heritage
- https://bunka.nii.ac.jp/heritages/detail/147715
- Hakone Tozan Railway, Selected Civil Engineering Heritage, Japan Society of Civil Engineers
- https://committees.jsce.or.jp/heritage/node/48
- Historic Steel Bridges Collection, Japan Society of Civil Engineers
- https://library.jsce.or.jp/jscelib/committee/2003/bridge/brtop.htm
- Hayakawa Bridge (Odakyū Hakone Railway Line), Japanese Wikipedia
- https://ja.wikipedia.org/wiki/早川橋梁_(小田急箱根鉄道線)
Last verified: 2026.08.13