Systems have certainly come along way from the days of John Saxby in the 19th century. Signalling and train control systems have become more complex and able to manage the world's railway networks in increasingly reliable and safe operations. But as demands change, so technology must continually evolve - and the next generation of systems are already in development. Upgrading the UK's ageing signalling system is not easy, and providing a painless solution while offering a significant speed increase on London's underground is a major challenge.