Mauritania
728 km
standard gauge: 728 km 1.435-m gauge (2008)
Mexico
total: 17,516 km
standard gauge: 17,516 km 1.435-m gauge (2008)
Moldova
total: 1,138 km
broad gauge: 1,124 km 1.520-m gauge
standard gauge: 14 km 1.435-m gauge (2008)
Mongolia
total: 1,810 km
broad gauge: 1,810 km 1.520-m gauge (2008)
Montenegro
total: 250 km
standard gauge: 250 km 1.435-m gauge (electrified 169 km) (2007)
Morocco
total: 1,907 km
standard gauge: 1,907 km 1.435-m gauge (1,022 km electrified) (2008)
Mozambique
total: 4,787 km
narrow gauge: 4,787 km 1.067-m gauge (2008)
Namibia
total: 2,629 km
narrow gauge: 2,629 km 1.067-m gauge (2008)
Nepal
total: 59 km
narrow gauge: 59 km 0.762-m gauge (2008)
Netherlands
total: 2,811 km
standard gauge: 2,811 km 1.435-m gauge (2,064 km electrified) (2008)