Laerdal vs Gotthard Base: length, opening date and class compared

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Side by side

Laerdal is recorded on data/tun10.html and Gotthard Base on data/rail.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

Laerdal opened in 2000 and Gotthard Base 16 years later in 2016, and that gap usually matters more than the length difference. The median railway tunnel in this archive measures 15.3 km, so both entries here are well clear of the ordinary case and the comparison is between two outliers rather than two typical crossings.

A 16-year gap spans real changes in ventilation, escape provision and excavation method, so the two were not built to the same standard. Laerdal belongs to the 2000s and Gotthard Base to the 2010s, two decades in which what a tunnel had to provide by way of escape and ventilation was not the same thing.

That gap is about 57 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 Laerdal or Gotthard Base has had.

At over twenty kilometres Gotthard Base sits in the small group of bores long enough to need intermediate ventilation and a full escape regime. Driven end to end the two would run 81.61 km, which is the figure to hold against the 57.1 km of the longest single railway tunnel in the record.

Laerdal and Gotthard Base are compared here on the figures this archive records for each, taken from the same sources and the same measurement convention. 19 other structures in this record opened within two years of Gotthard Base, which is the cohort it was designed alongside and the fairer comparison for how it was built.

Reading the figures

Across every class this archive records, Gotthard Base stands 1st by length and Laerdal 20th, so the pair sits inside the top 20 of 244 structures. Counting every class, 18 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.

Gotthard Base is the longer of the two at 57.1 km, ahead of Laerdal at 24.51 km, a difference of 32.59 km. The 2000s account for 53 entries in this archive, and Laerdal is one of them, which is the context a single opening date does not carry on its own.

Laerdal is recorded as a road tunnel and Gotthard Base as a railway tunnel, so the two are measured the same way but built to different constraints. Subaqueous tunnels are governed by rock cover above the bore rather than by the depth of water above that, which is why depth and length are separate records.

Gotthard Base is the longest railway tunnel in this archive, which makes this comparison one against the record itself rather than two entries below it. Both pass ten kilometres, which 161 of the 244 structures recorded here manage, so this is a comparison inside a small group rather than across the field.

Comparing two national records says as much about how each country documents its infrastructure as about the infrastructure. A ruling gradient set by the heaviest train decides whether a rail crossing needs a tunnel at all. Smoke moves uphill, so the two portals of a burning tunnel are not equally dangerous.