Abstract
Researching the origin of railway gauge 4 ft 8.5 in (1435mm), field survey has been done in Turkey, Central Asia and India. In this report, Pompei and Ercolano of Roman ruins where they are buried by eruption of Volcano Vesuvio at 79 A. D. are surveyed. Many wheel ruts of Roman chariots were found and their gauges were measured. The measured results are very nearly equal to present international railway standard gauge. Accordingly, the origin of railway gauge is in wheel rut of chariot at Roman Empire.