Tunnels and Viaducts on the SS340 in Italy, by Kilometre Point

• 19entries listed
• 3.54 kmlongest bore
• 19.23 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 9.28 km of the 19.23 km on this page, which is 48 per cent of the total from 3 of 19 rows. The shorter half of the table totals 1.78 km against 17.44 km for the longer half, from the same number of rows.

Between the longest and the tenth-longest the drop is 2.9 km, which is the part of the table that changes when a single scheme opens. Where one of these 19 lengths disagrees with an operator's own figure for Italy, the table keeps the published value and notes the difference instead of averaging the two.

Lengths for Italy are recorded in metres which is how the operators publish them and why the shortest entry here reads as 53 m and not a rounded figure. The longest entry is 66.7 times the shortest and 5.6 times the median, which is the quickest measure of how uneven the table is.

Also recorded here are Loveno at 1.74 km and Brienno at 1.15 km. A tunnel list for Italy reads differently from a neighbouring country's: 2 of these 19 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.

A new scheme in Italy would have to beat 3.54 km to change the head of this table, and that is the figure worth rechecking when one opens. A freight route's ruling gradient is set by the heaviest train it must lift, and that single figure decides whether a tunnel is needed at all.

Reading the figures

The eighth longest is San Nicolao at 1.05 km, which is about where this record stops being about record holders and starts being about ordinary infrastructure. The ten longest average 1.74 km against 0.2 km for everything below them, and that ratio is the clearest thing this table says about the distribution.

Laid end to end the entries on this page would run 19.23 km, which is a number with no engineering meaning but a useful sense of the scale of what is catalogued. The oldest entries in any national list are usually canal or rail, because roads were the last mode to need long bores.

The material on this page is held in 3 captions rather than in running text, 26 words of it, each written against the image or row it belongs to by the compiler who put the page together. The kilometre point is recorded for each structure on the SS340, which is how the operator identifies it.

The note column records 1 exits and 6 motorway connections along the route, in running order rather than by size. Read down the length column, the 12 values run from 53 m to 3 314 m with a midpoint at 338 m; the spread rather than the maximum is what says how uneven this set is.

The 12 entries are grouped on the page under 3 headings — connection ss340 / a9 motorway (6), menaggio / connection ss 340 dir (5) and ch border (1) — a classification the table carries as section breaks rather than as a column of its own. Italian motorway inventories list tunnels and viaducts together in running order along the SS340.