To see a sphere whizzing about trailing plumes of steam while flames licked ... but seeing a modern replica of Hero’s Engine built and tested probably isn’t too far from such an experience.

In fact, it's almost possible to see steam as a realistic alternative to modern engines. Scroll down to watch Professor Leno give you an inside look at his idea of the pinnacle of the steam ...

The best modern engines show, by the indicator cards, between 60 and 90 per cent of the theoretical effect of the steam ; in all cases the figures vary in proportion as care is exercised'in ...

Some factory owners did replace steam engines with electric motors, drawing clean and modern power from a nearby generating station. But given the huge investment this involved, they were often ...