In 1910, the world's first fully operational driverless railway opened below the streets of Munich. Although the train carried no passenger, only mail for the Post Office, it was hailed as having revolutionary implications for the future of rail travel in general.
Decades later, despite the use of modern technology - closed-circuit televisions to monitor the movement of passengers on both the train and the platform, and microprocessors that can perform all the tasks of a human crew on a conventional train - just 20 passenger-carrying railways around the world use automatic trains and only a few of these are completely unmanned. An attendant is usually on board to control doors, start the train and cope in an emergency.
Why is it that such a labour-saving and therefore economical system has had such little success? Research shows that passengers are reluctant to travel on trains without drivers because they fear they are not safe. But, since the first fully automatic unmanned system was introduced, in Lille, France, in 1983, the indications are that these trains are as safe as - if not safer than - those with drivers. Once an automatic computerised system detects an object on the line, for example, it can operate the emergency brake far faster than the most alert driver.