'The lesson is, always have an alternative Plan B ready,' said Kao, who added that he had already passed this advice on to Weng Zhensong, a key researcher at Beijing's Ministry of Railways.

Kao and Weng were speakers at the China Railway Innovation Summit in Beijing earlier this month.

'The mainlanders are very smart, so they will make the high-speed rail succeed. They always have a Plan B,' said Kao, without identifying what Plan B was.

As for Taiwan's high-speed rail service, Kao had this judgment: 'Is it successful? Not yet. Ridership was not as expected.'

As of September last year, Taiwan's high-speed rail service was being used by just 30 per cent of the forecast 90,000 daily passengers, data provided by Kao shows.

Although ridership doubled from 1.55 million in 2007 to 3.06 million and sales revenue grew 70 per cent to NT$23 billion (HK$5.5 billion) last year, Taiwan High Speed failed to pay NT$300 million in interest it owed the Ministry of Transportation and Communications, the Taipei Times said.

'The Taiwan high-speed rail needs another 50,000 passengers per day to pay back its investment. The Taiwan government and the private sector are now trying to resolve the issue,' said Kao.

By the end of June this year, it had accumulated losses of more than NT$70 billion, or about 66 per cent of its paid-up capital of NT$105.3 billion, and debts of more than NT$400 billion, Taiwan media said.

To explain the lack of success required an understanding of the service's history, said Kao.

In the late 1980s, two competing consortiums bid for Taiwan's high-speed rail. The China High Speed Rail Consortium was led by firms backed by the Kuomintang and Japanese suppliers, while the winning consortium, Taiwan High Speed, was led by a handful of young entrepreneurs, five private fims including Fubon Bank and European partners.

The latter consortium was friendlier to the ruling Democratic Progressive Party led by Chen Shui-bian, who was Taiwan's president from 2000 to last year, said Kao.

Taiwan High Speed won the bid because it 'made an offer the Taiwan government could not resist', he said.

While China High Speed asked the government to invest NT$149.5 billion, Taiwan High Speed requested a NT$105.7 billion loan from the government which it would repay.

As a result, Taiwan High Speed signed a 35-year agreement, estimated at US$13.2 billion, to build and operate the high-speed rail in 1998, which was then the world's largest build-operate-transfer project.

'Taiwan's high-speed rail has problems because it has no government funding. If it had government funding and subsidies, it would be successful and have no problems,' said Kao.

Another reason for the low ridership was the two million Taiwanese businessmen expected to use this train had moved to work on the mainland, Kao added. 'Ridership was disappointing. The people who are supposed to be riding this train are on the mainland.'

Nevertheless, Kao expected ridership of the mainland's high-speed trains to be high because of pent-up demand, as it is difficult to get tickets for ordinary trains on the mainland during peak seasons.

The mainland's high-speed train tickets would be affordable to mainlanders because they were likely to be subsidised by the government, which would probably be willing to recover costs over many years, added Kao.

Another reason for the poor performance of Taiwan's high-speed rail was the distant location of its stations from city centres, which made travelling to these stations costly and inconvenient, said a Taiwanese lawyer.

The Guangzhou-Shenzhen-Hong Kong express rail link has been criticised recently for the site of its Guangzhou station in Shibi, in the city's southwest fringe far from the city centre. The service is scheduled to start in 2015.