Railway Tunnels in the United States — Complete List by Length

• 5entries listed
• 12.54 kmlongest bore
• 1876–1970openings span
• 44.04 kmtotal length

The record table

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

How this table is compiled

Roughly 0 of the dated entries opened in this century, which is a rough measure of how much of the network is recent. The captions name 13 distinct places and structures — Northern, Railway and Cascade among them — and those names are the index into the length tables where each is recorded with its own figure.

The middle half of the table runs from 5.1 km to 11.92 km, and that band is where most of the engineering on this page actually sits. The longest entry is 4.9 times the shortest and 1.3 times the median, which is the quickest measure of how uneven the table is.

The longest entry is New Cascade, at 12.54 km, opened in 1929. A tunnel list for the United States reads differently from a neighbouring country's: 4 of these 5 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.

The shortest recorded entry is 2.56 km against 12.54 km at the top, a spread of 4.90x across the same table. Where one of these 5 lengths disagrees with an operator's own figure for the United States, the table keeps the published value and notes the difference instead of averaging the two.

4 of the 5 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 44.04 km, which is a number with no engineering meaning but a useful sense of the scale of what is catalogued.

Reading the figures

A new scheme in the United States would have to beat 12.54 km to change the head of this table, and that is the figure worth rechecking when one opens. Dates for the United States refer to opening to traffic, not breakthrough, so the 1876 entry was under construction for some years before that.

The earliest dated entry is Hoosac, opened in 1876, and the most recent is Flathead in 1970. Read down the length column, the 5 values run from 2 557 m to 12 537 m with a midpoint at 9 996 m; the spread rather than the maximum is what says how uneven this set is.

The table on this page runs to 5 rows and records Tunnel, Length, Date of opening and Line, comment for each of them, which is the shape the original compiler chose rather than one imposed here. Tunnel building in the United States is shaped by geology and settlement pattern as much as by transport policy.

The entries sum to roughly 44.04 km of bore, an average of about 8.81 km each, though that average describes no actual row. The tunnel column names 5 distinct entries on this page, New Cascade and Flathead among them, each traceable to the operator or administration record it was taken from.

3 of the 5 entries fall within a quarter of the median length, which is how tightly this particular list clusters around its typical structure. 2 entries sit within ten per cent of the longest, so the head of this record is a close group, not one structure standing clear.