381/380

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381/380, the five feet comma, is the 127-limit ratio that is the difference between the 127/64 and 95/48.

Interval information

Ratio	381/380
Subgroup monzo	2.3.5.19.127 [-2 1 -1 -1 1⟩
Size in cents	4.549895¢
Name	five feet comma
Color name	127o19ug1
FJS name	[math]\displaystyle{ \text{d2}^{127}_{5,19} }[/math]
Special properties	superparticular, reduced
Tenney norm (log2 nd)	17.1435
Weil norm (log2 max(n, d))	17.1473
Wilson norm (sopfr(nd))	158
Comma size	small
Open this interval in xen-calc

Trivia

It represents the difference between 1524 mm railway gauge and the 1520 mm, which were used interchangeably in the areas of the former Soviet Union and Russian Empire. Such an approach did result in wear of the train undercarriage, but it wasn't significant enough of a difference and it was therefore applied for a certain time.

Links

• Wikipedia Contributors, 5 ft and 1520 mm gauge railways.