Title: History and Present State of Railway Tunnels in Japan (5th Report)
Abstract: History of railway tunnels in Japan was traced in 1st to 4th reports, and it was found that the tunnels in Meiji Era had a wide variety of portal designs. Objects of these reports were confined railway tunnels on Honsyu Island, the present report describes tunnels of defunct Kyusyu Railway Company (now a part of Kagoshima Line, Nagasaki Line, Sasebo Line and their branch lines of JR-Kyusyu Company; and Tagawa Line of Heisei-Chikuhou Railway Company) in northern district of Kyusyu Island. The description is based on field surveys and historical records. The contents may be summarized as follows; (1) the design of portal is similar to that on Honsyu Island, but in details characteristic styles are recognized; (2)“gable type” portal similar to one on Honsyu Island was newly discovered; and (3) the portal of the longest tunnel in Kyusyu is designed in special style.