Why are governments so taken with high speed rail?

First off, there's the 'green' vote – 'greenhouse gas' emissions can be up to 90% lower than flying. It makes economic sense too – better transport links mean a more mobile, productive workforce, which makes life cheaper for companies. And rail schemes are also big employers. The Beijing-Shanghai link alone employs 110,000 workers.

In the US, $8bn of stimulus funds has been set aside for high speed rail projects. A $2.7bn project in Florida is set to open in 2015, and a Los Angeles-to-San Francisco link costing upwards of $40bn should open in 2020. And on Tuesday 28 September, Amtrak unveiled a $117bn, 30-year vision for a high speed rail line linking the entire East Coast.

Political grandstanding by the Republicans may cause problems for some of these projects. But the US is just one of many countries looking at high-speed rail. Here in Britain, construction on a line linking London to the cities of Birmingham, Manchester and Leeds is due to start in 2015. And projects are also underway in Spain, Italy, South Korea and India.