The project was initiated in the 1960s, with the objective of providing a continuous 8750 mile (14,000km) rail link between Singapore and Istanbul, Turkey, with possible further connections to Europe and Africa. At the time shipping and air travel were not as well developed, and the project promised to significantly reduce shipping times and costs between Europe and Asia. Progress in developing the TAR was hindered by political and economic obstacles throughout the 1960s, 1970s and early 1980s. By the 1990s, the end of the cold war and normalisation of relations between some countries improved the prospects for creating a rail network across the Asian continent.
The TAR was seen as a way to accommodate the huge increases in international trade between Eurasian nations and facilitate the increased movements of goods between countries. It was also seen as a way to improve the economies and accessibility of landlocked countries like Laos, Afghanistan, Mongolia, and the Central Asian republics.
Much of the railway network already exists, although some significant gaps remain. A big challenge is the differences in rail gauge across Eurasia. Four different major rail gauges (which measures the distance between rails) exist across the continent: most of Europe, as well as Turkey, Iran, China, and the Koreas use the 1435 mm gauge, known as Standard gauge; Finland, Russia, and the former Soviet republics use a 1520 mm gauge; most of the railways in India, Pakistan, Bangladesh and Sri Lanka use a 1676 mm gauge, and most of Southeast Asia has metre-gauge. For the most part the TAR would not change national gauges; mechanized facilities would be built to move shipping containers from train to train at the breaks of gauge.
A big obstacle is also the need of sea transport to Japan and South Korea. A container ship has room for much more containers than a train. Therefore ships must go less regular than trains, creating a big delay. There are hopes to create an overland connection through North Korea, however there is still a break-of-gauge.
By 2001, the four corridors had been studied as part of the plan:
One can not say that the Trans-Asian Railway Project has been a great success so far. Very little railway has been built along the corridors during the 40 years. The Northern Corridor was working already in the 1960s, although only for Soviet Union-China trade. Success so far include: