High-speed rail (HSR) has developed in Europe as an increasingly popular and efficient means of transport. The first high-speed rail lines on the continent, built in the 1970s, 1980s and 1990s, improved travel times on intra-national corridors. Since then, several countries have built extensive high-speed networks, and there are now several cross-border high-speed rail links. Railway operators frequently run international services, and tracks are continuously being built and upgraded to international standards on the emerging European high-speed rail network.