Usui Daisan Bridge (Megane Bridge)
Interesting facts
- Within a year of completion the bridge showed signs of deformation, so its piers and arches had to be heavily reinforced in 1894.
- The Abt section over the Usui Pass climbed at a gradient of 66.7 per mille, about 1 in 15, among the steepest on any Japanese main line.
- The 11.2 km rack railway between Yokokawa and Karuizawa needed 18 bridges and 26 tunnels to cross the pass.
- Steam smoke trapped in the many tunnels was so dense that crews suffered breathing injuries, which pushed the line to switch to electric traction in 1912.
- Electrification in 1912 cut the climb over the pass from about 80 minutes to about 40, one of the earliest main-line electrifications in Japan.
- Its 1993 designation made it, with the other Usui Pass structures, the first brick structures in Japan listed as Important Cultural Properties.
- Early Abt locomotives for the pass were built in Britain by Beyer, Peacock and Company, including the Class 3920 delivered in 1895.
- After 1963 the replacement line used powerful EF63 banking locomotives, until the whole Yokokawa to Karuizawa section closed in 1997 with the Nagano Shinkansen.
Why it is worth it
Where the old Shin'etsu line climbed the Usui Pass between Gunma and Nagano, the railway engineers of the Meiji era had to lift trains up a steep mountain grade. Their answer was a rack railway on the Abt system, and to carry it across the gorges they built a series of brick viaducts. The largest of them, the Usui Third Bridge, is the one everyone knows by its nickname, Megane-bashi — the "spectacles bridge" — for the round arches that open through it like lenses.
Work began in 1891 and the bridge was finished in 1893. It is 91 metres long and stands 31 metres above the riverbed on four arches, and it took around two million bricks to build — it is described as the largest brick arch bridge in Japan. The design is credited to the British engineer Charles Pownall, who had come to Japan in 1882, working with the Japanese engineer Furukawa Haruichi. Looking at it from below, what stands out is how light the structure seems for its bulk: tall, narrow piers, high semicircular arches and warm red brickwork set against the forested slopes of the pass.
Rack working over the pass ended in 1963, when a new line was opened, and the old bridges and tunnels were left behind. In 1993 the Usui Pass railway structures were designated an Important Cultural Property — the first railway facilities in Japan to receive the status. The disused trackbed has since become a walking trail, the Abt Road, which runs about six kilometres through tunnels and over bridges from the Yokokawa side of the pass; its full length opened in 2012.
Getting there
The bridge stands in Annaka, Gunma Prefecture, about 6 km from Karuizawa on the Nagano side of the pass. The nearest airport is Shinshu-Matsumoto (MMJ), about 73 km away in a straight line. From Yokokawa station the bridge is about 15 minutes by bus, or about an hour and a half on foot along the Abt Road.
On these lists
From the encyclopaedia
Usui Bridge is the largest brick-masonry arched bridge in Japan, located over Usui river in Gunma prefecture. The bridge was built in 1892 for the Usui Railway Line to travel between Yokokawa in Gunma Prefecture and Karuizawa in Nagano Prefecture. It was designed by a British engineer Charles Assheton Whately Pownall during the Meiji era, with some of the piers reaching heights of up to 110 feet (34 m).
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