Asian nations have agreed to form a network of railroads that aims to connect 28 countries in the region to each other and Europe.  The Trans-Asian Railway holds out the promise of improved trade, transport, and integration.  But, forming the massive network is no small challenge.

The agreement to form a Trans-Asian Railway Network has been in the works since the 1960s, but was held up by wars and ideological conflict.

The U.N.-sponsored agreement finally came into force Thursday, after the last of eight Asian nations, the minimum number required, signed on.

The agreement commits the countries to coordinate the development and operation of international rail routes that would eventually link 28 nations in the region.

Noeleen Heyzer is the executive secretary of the U.N. Economic and Social Commission for Asia and the Pacific.  Speaking at a ceremony in Bangkok marking the event, she said the rail network would help form the "backbone" of regional trade.

"This would be a tremendous opportunity not just to improve the physical infrastructure, but also the governance infrastructure, as well as the human capacity infrastructure of our region as we become a more coordinated Asia," said Heyzer.

The connecting rail arteries would span from Turkey to China to Singapore, and would open up land-locked nations and remote areas to development.

Heyzer said the timing of the agreement was particularly significant as Asia is looking to promote trade and investment to stimulate economic recovery.

The planned network would be made up of 114,000 kilometers of railway lines, linking stations designed as "dry" trading ports to coastal ports

But 8,300 kilometers of the rails have not been built and will cost an estimated $25 billion.   Billions more will have to be spent on upgrading existing railroads.

Heyzer says the countries would also have to work out cross-border problems, including technical and legal standards and customs procedures.

But she held out hope they would only need a matter of years to sort out the problems, rather than the decades it took to agree to form the Trans-Asian Railway.