Ryfylke vs Eiksund: length, opening date and class compared

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Side by side

Ryfylke is recorded on data/tun10.html and Eiksund on data/subsea.html, compiled to the same convention, which is what makes the two figures comparable at all.

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

How this table is compiled

Neither holds the record: Laerdal at 24.51 km is the longest road tunnel recorded here, 10.05 km ahead of Ryfylke. Ryfylke is 1.85 times the length of Eiksund, and it is the ratio rather than the 6.66 km that says how differently the two crossings had to be ventilated and escaped.

Ryfylke and Eiksund are compared here on the figures this archive records for each, taken from the same sources and the same measurement convention. Ryfylke belongs to the 2010s and Eiksund to the 2000s, two decades in which what a tunnel had to provide by way of escape and ventilation was not the same thing.

Ryfylke is the longer of the two at 14.46 km, ahead of Eiksund at 7.8 km, a difference of 6.66 km. Driven end to end the two would run 22.26 km, which is the figure to hold against the 24.51 km of the longest single road tunnel in the record.

That gap is about 46 per cent of the longer bore, which is the figure worth holding on to rather than the raw metres. Both rows are reachable from the road tunnel table they were taken from, where the note column carries the tube count, the gradient and any reconstruction Ryfylke or Eiksund has had.

Ryfylke is recorded as a road tunnel and Eiksund as a subaqueous tunnel, so the two are measured the same way but built to different constraints. 14 other structures in this record opened within two years of Ryfylke, which is the cohort it was designed alongside and the fairer comparison for how it was built.

Reading the figures

Counting every class, 82 recorded structures fall between these two by length; the comparison is a window on that part of the record rather than a gap in it. Ryfylke passes ten kilometres and Eiksund does not, which puts them in different operating regimes for ventilation and escape whatever the raw difference in metres says.

Across every class this archive records, Ryfylke stands 83rd by length and Eiksund 166th, so the pair sits inside the top 166 of 244 structures. The 2000s account for 53 entries in this archive, and Eiksund is one of them, which is the context a single opening date does not carry on its own.

A 11-year gap spans real changes in ventilation, escape provision and excavation method, so the two were not built to the same standard. Figures are checked against one another where they differ. Where a crossing has two bores of different lengths, the longer governs the comparison and both are recorded on the source table.

A comparison of two crossings is a comparison of two ground conditions, and the length column records neither. Pumps run for the life of a subaqueous crossing and are the one system that is never switched off. Compressed-air working made shafts through wet ground possible at a cost paid by the men who sank them.

Ryfylke was designed under the modern regime, with cross-passage spacing and emergency ventilation specified from the outset. 82 recorded structures are longer than Ryfylke, the nearest of them Zigana at 14.48 km. A structure renamed after opening keeps both names in circulation for years afterwards. Sources are named on each structure's own table.