381/380
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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]\text{d2}^{127}_{5,19}[/math]
Special properties
superparticular,
reduced
Tenney height (log2 nd)
17.1435
Weil height (log2 max(n, d))
17.1473
Wilson height (sopfr(nd))
158
Harmonic entropy
(Shannon, [math]\sqrt{nd}[/math])
~1.39107 bits
Comma size
small
open this interval in xen-calc
| Interval information |
reduced
(Shannon, [math]\sqrt{nd}[/math])
381/380, the five feet comma, is the 127-limit ratio that is the difference between the 127/64 and 95/48.
Real life
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.