Former JNR Miyanoharu Line

The Miyanoharu Line: 26.6 Kilometres from Era to Higo-Oguni

The Former JNR Miyanoharu Line (旧国鉄宮原線, Kyū Kokutetsu Miyanoharu-sen) was a Japanese National Railways branch line between Era Station in Kokonoe, Oita Prefecture, and Higo-Oguni Station in Oguni Town, Kumamoto Prefecture; seven concrete arch bridges built on its Kumamoto section between 1937 and about 1939 survive in Oguni and were registered together as a Registered Tangible Cultural Property in 2004.

The name trips up even Japanese readers. The kanji 宮原 would usually be read Miyahara, but the line was always the Miyanoharu-sen, and the Agency for Cultural Affairs keeps that reading in its records.

The line ran 26.6 kilometres. It left the Kyudai Main Line at Era, wound through the hills, crossed the Oita and Kumamoto border and ended in the market town of Oguni. It was completed through to Higo-Oguni only in 1954, carried commuters, schoolchildren and timber from the surrounding forests, and was closed in 1984 under the national railway reconstruction law. It was the first JNR line in Kyushu to go. Trains used it for barely thirty years.

The bridges are older than the service they were built for. They went up between 1937 and about 1939, and then waited well over a decade for the first train to Higo-Oguni. The Agency for Cultural Affairs describes them as a set of plain, unreinforced concrete arches built in line with a wartime policy of saving steel.

Seven Bridges in a Row

Pieced together from the Agency's own descriptions, the order from the Higo-Oguni end runs Konogawa, Kitazato, Doyama, Shioigawa, Horita, Sugenosako and Hirodaira. Konogawa stands between Higo-Oguni and Kitazato stations; Kitazato sits right beside the old Kitazato Station; the other five are scattered along the valleys between Kitazato and the Oita border.

They vary a great deal in size. Sugenosako is the giant, eleven arches and 136 metres long, with a pier 23 metres tall, the longest and highest on the line. Konogawa has the widest arches at 20 metres. Hirodaira goes the other way, stringing together nine small arches of 7 metres. Doyama and Shioigawa are compact three-arch bridges that face each other across a small green hill.

What they share is a single-track deck and a filled, or closed-spandrel, construction in which the wall between arch and deck is solid concrete. The piers all flare toward the base, and three of the bridges, Kitazato, Horita and Hirodaira, follow a curve. It helps to think of one design idea stretched seven different ways to fit seven different valleys.

Walking the Old Line

About 4 kilometres of the trackbed, from Michi-no-Eki Oguni Yu Station (the former Higo-Oguni Station) to the old Kitazato Station, have been turned into a walking path by the town. The route passes above Konogawa Bridge, runs through a tunnel and crosses Kitazato Bridge just before the end. These two are the easy ones to reach on foot; the other five lie off the path and are best approached by car.

The town asks walkers to use the car parks and toilets at Yu Station and at Mokkonkan, a training and exchange centre in Kitazato. The full path out and back is about 8 kilometres, so a shorter option is to start at Mokkonkan and turn around at Konogawa Bridge, roughly forty minutes there and back. The path is used at your own risk; take litter home, keep noise down near houses, and leave the trackbed once the light starts to fade.

For a guided walk, the Oguni Guide Club takes bookings for the Miyanoharu Line route. Apply at least one week ahead; fees are agreed by phone.

Getting to Oguni

From Fukuoka, highway buses bound for Kurokawa Onsen leave Hakata Station and Fukuoka Airport and reach the Yu Station stop in about two and a half hours; reservations are required. From Kumamoto, take the JR Hohi Line to Ozu, then a local bus to Aso Station and a connection to Yu Station, or use the Ogunigo Liner. Buses are infrequent everywhere in this area, so check the timetable before you set out.

By car, leave the Oita Expressway at Hita and follow Route 212 toward Aso, about two hours from Fukuoka, or exit at Kokonoe and take Route 387, about thirty minutes.