Turkmenistan
total: 2,980 km
broad gauge: 2,980 km 1.520-m gauge (2008)
Uganda
total: 1,244 km
narrow gauge: 1,244 km 1.000-m gauge (2008)
Ukraine
total: 21,658 km
broad gauge: 21,658 km 1.524-m gauge (9,729 km electrified) (2009)
United Kingdom
total: 16,454 km
broad gauge: 303 km 1.600-m gauge (in Northern Ireland)
standard gauge: 16,151 km 1.435-m gauge (5,248 km electrified) (2008)
United States
total: 226,427 km
standard gauge: 226,427 km 1.435-m gauge (2007)
Uruguay
total: 1,641 km (1,200 km operational)
standard gauge: 1,641 km 1.435-m gauge (2010)
Uzbekistan
total: 3,645 km
broad gauge: 3,645 km 1.520-m gauge (620 km electrified) (2008)
Venezuela
total: 806 km
standard gauge: 806 km 1.435-m gauge (2008)
Vietnam
total: 2,347 km
standard gauge: 178 km 1.435-m gauge
narrow gauge: 2,169 km 1.000-m gauge (2008)
World
total: 1,138,632 km (2008)