High speed systems around the world are being built to standard gauge, evin if the home country (Spain, Japan, and Taiwan, for example) uses another gauge for its conventional system.

There is a move in Europe to integrate the formerly separate national rail networks into a single european network with common technical specifications, signaling systems, and the like, and some big infrastucture projects that will create trans-european high-speed and freight networks.

Asia is divided into several large "gauge oceans" of differing gauges; Western Asia, including Turkey and Iran, are predominantly standard gauge, as is China; the Indian Subcontinent is mostly the 5' 6" gauge; Russia and the Central Asian republics are mostly 5' gauge; and Southeast Asia is mostly meter gauge. Projects across Asia, like the Bosporus rail bridge, a standard gauge railway connecting China and Iran across Kazakhstan and Turkmenistan, and the linking up of the Iranian and Pakistani rail networks across southeast Iran, are slowly knitting together Eurasia into a single network, although with several major breaks of gauge. It will be interesting to see whether the advent of Peak Oil and Global Climate Change will create a push for more linked up, inter-operable, and electrified rail networks across large regions.