Railway Tunnels in Japan — Complete List by Length

• 79entries listed
• 53.85 kmlongest bore
• 1931–2004openings span
• 698.96 kmtotal length

The record table

How this archive measures: lengths, bores, dates and ordering

How this table is compiled

The three longest entries alone account for 101.88 km of the 698.96 km on this page, which is 15 per cent of the total from 3 of 79 rows. The shorter half of the table totals 221.93 km against 477.03 km for the longer half, from the same number of rows.

Where one of these 79 lengths disagrees with an operator's own figure for Japan, the table keeps the published value and notes the difference instead of averaging the two. The 79 rows for Japan are ordered by length, not by date, so the 2004 opening sits well down the table without being any less current.

79 of the 79 measured entries exceed five kilometres, and those are the ones that carry a full ventilation and escape regime. Laid end to end the entries on this page would run 698.96 km, which is a number with no engineering meaning but a useful sense of the scale of what is catalogued.

A new scheme in Japan would have to beat 53.85 km to change the head of this table, and that is the figure worth rechecking when one opens. The longest entry is 10.7 times the shortest and 8.1 times the median, which is the quickest measure of how uneven the table is.

Second and third place go to Iwate-ichinohe at 25.81 km and Dai-shimizu at 22.22 km. Read down the length column, the 79 values run from 5 045 m to 53 850 m with a midpoint at 6 640 m; the spread rather than the maximum is what says how uneven this set is.

Reading the figures

Eighth on the list is Nakayama at 14.86 km, which is where the table stops being about record holders and starts being about ordinary infrastructure. The ten longest average 20.96 km against 7.09 km for everything below them, and that ratio is the clearest thing this table says about the distribution.

The dated entries fall across 28 different years, which is a rough measure of whether this was a sustained programme or a handful of separate schemes. The tunnel name column names 79 distinct entries on this page, Seikan and Iwate-ichinohe among them, each traceable to the operator or administration record it was taken from.

The table on this page runs to 79 rows and records Tunnel name, Length, Date of opening, No. of tracks and Line, notes for each of them, which is the shape the original compiler chose rather than one imposed here. Base tunnels driven low through a massif appear here beside the older summit tunnels they replaced.

The longest entry is Seikan, at 53.85 km, opened in 1988. 79 of the 79 rows carry an entry in the line, notes column — 100 per cent of the table — and that column is where the qualifications live: tube counts, closures, boundaries and the reason a figure reads the way it does.

Further down the table, Rokk is recorded at 16.25 km and Haruna at 15.35 km. A tunnel list for Japan reads differently from a neighbouring country's: 79 of these 79 structures pass three kilometres, and the same journey time is bought with one long bore in one country and a dozen short ones in another.