- 1830 CE: The Liverpool and Manchester Railway (LM&R) introduced standard-gauge railway (4' 8.5", or 1435 mm)
- 1843 CE: The Russian Empire chose 5' or 1524 mm for their railway gauge
- 1850 CE: The Great Indian Peninsula Railway% began work on a broad gauge railway of 5' 6" or 1680 mm, which became the standard gauge in India, Pakistan, Bangladesh, Sri Lanka, Argentina, and Chile
- 1862 CE: The Pacific Railroad Acts specified standard-gauge (4' 8.5", or 1435 mm) for the USA
- 1865 CE: The Queensland Railways built a narrow gauge railway of 3' 6" or 1067 mm
- 1866 CE: Southern railroads in the USA converted from Russian gauge (5' or 1524 mm) to standard-gauge (4' 8.5", or 1435 mm)
- 1870 CE: New Zealand adopted a narrow gauge railway of 3' 6" or 1067 mm
- 1871 CE: Java adopted a narrow gauge railway of 3' 6" or 1067 mm
- 1872 CE: Japan opened its first narrow gauge railway of 3' 6" or 1067 mm
- 1873 CE: The Cape Colony (present day South Africa) adopted a narrow gauge railway of 3' 6" or 1067 mm
- 1970 CE: The Soviet Railway redefined the railway gauge from 5' or 1524 mm to 1520 mm.