BBC News, Hong Kong
Train lovers and travel nuts have long had a dream of going from Europe to Singapore by rail.
The journey to the East goes well as far as China, and the upgrading of tracks - sometimes with high-speed trains - is easing passage as far as Hong Kong.
From then on south, the rail buff, and potential cargo carriers, must wait just a few more years.
From south China into South East Asia is a bigger leap than it looks on the map - and not only for trains.
Diplomacy and funding from France and the Asian Development Bank (ADB) have been agreed for the next step, from China to the Vietnamese capital of Hanoi.
And there are more routes being built from Kunming in the Chinese province of Yunnan.
Regional transport specialists told the BBC that two-thirds of the line from Kunming to the Chinese side of the border is completed, and a project is under way on the Vietnamese side to Lao Khai on the border.
Dreams to reality
Moving southwards through Vietnam, the aged track from Hanoi in the north to the southern hub of Ho Chi Minh City (formerly Saigon) in the south does daily duty for thousands.
It works, but is old and needs upgrading.
Even more urgent for the Vietnamese government are the urban rail projects it announced in September.
At least $15bn (£9.7bn) is to be spent on building tramways, sky trains and subways within Hanoi, and a metro in Ho Chi Minh City.
In Hanoi, complex upgrading works are being propelled by Japanese and French assistance; Japan is funding a feasibility study into elevating the entire urban railway, and a metro line is planned between the airport and the city.
"It has moved from the realm of dreams to reality - just give it a couple of years," said Peter Broch, a transport economist in the ADB's South East Asia regional department.
In Cambodia, the entire national network is now being overhauled, rehabilitated and privatised, with the help of a foreign investor and multilateral funding.
"It's reaching the point where things are falling into place," Mr Broch said.
Getting from Vietnam to the Cambodian capital, Phnom Penh, remains difficult.
The terrain demands several challenging bridges, feasibility studies for which have been funded by China.
A route has been identified to meet the Vietnamese border at Loc Ninh, which suits Vietnamese mining interests in the area.
But the money has not yet been found to meet the costs of the project of up to $500m.
Getting from Phnom Penh further westward into Thailand is perhaps the most startling difficulty, ever since the Khmer Rouge ripped up the train lines between their strongholds in north-west Cambodia and the border.
The Thai government is fixing up the six missing kilometres (nearly four miles) of track on their side.
Contractors are now working on the 48 km missing on the Cambodian side, from Sisophon to Poipet, the ADB said.
Just a few kilometres are missing between Thailand and Laos.
It is now agreed that the Thai government will pay for the rail track over the Friendship Bridge that crosses the Mekong River between the two countries.
Once it reaches a rail head on the other side of the river, a few more kilometres are needed for it to reach the Laotian capital Vientiane.
Other links are on the drawing boards, if the mountains and rivers can be tamed.
One idea is to link Chinese rail southward through Laos along the Mekong River, although the technical challenges presented by the dramatic landscapes would make this expensive.
That would still be easier than linking China to the south seas through Burma, where huge mountain ranges - and a cash-strapped government of ruling generals - bar the way.
But Mr Broch noted that the approach towards railways of countries in the region grouped under the Greater Mekong Sub-region (GMS) has become much more committed.
He and his colleagues have been asked by regional governments to upgrade recent transport plans "with a view to multi-modal transport", meaning the swapping of containers from trucks to trains and back.
"I think it goes to show that where railways were seen as peripheral before, there is now a major policy shift.
"Governments are realising the need for high capacity, ever-increasing cargo traffic, and they need a mode of transport less intrusive than roads," said Mr Broch.
He predicted it would be possible to catch a train, or put a container on a train, from Singapore to Phnom Penh within two years, and from Phnom Penh to Ho Chi Minh City within five years.
A train ride along the banks of the Mekong might take a little bit more time.