Turkey
total: 8,697 km
standard gauge: 8,697 km 1.435-m gauge (2,122 km electrified) (2004)
Turkmenistan
total: 2,440 km
broad gauge: 2,440 km 1.520-m gauge (2004)
Uganda
total: 1,241 km
narrow gauge: 1,241 km 1.000-m gauge (2004)
Ukraine
total: 22,473 km
broad gauge: 22,473 km 1.524-m gauge (9,250 km electrified) (2004)
United Kingdom
total: 17,274 km
standard gauge: 16,814 km 1.435-m gauge (5,296 km electrified)
broad gauge: 460 km 1.600-m gauge (in Northern Ireland) (2004)
United States
total: 227,736 km
standard gauge: 227,736 km 1.435-m gauge (2003)
Uruguay
total: 2,073 km
standard gauge: 2,073 km 1.435-m gauge
note: 461 km have been taken out of service and 460 km are in
partial use (2004)
Uzbekistan
total: 3,950 km
broad gauge: 3,950 km 1.520-m gauge (620 km electrified) (2004)
Venezuela
total: 682 km
standard gauge: 682 km 1.435-m gauge (2004)
Vietnam
total: 2,600 km
standard gauge: 178 km 1.435-m gauge
narrow gauge: 2,169 km 1.000-m gauge
dual gauge: 253 km three-rail track combining 1.435-m and 1.000-m
gauges (2004)