London's underground train services, which are run by Transport for London. The first underground railways in London were begun in the 19th century, and were the first of their kind in the world. The 11 lines of the system (usually known as the Underground or informally as the Tube) are connected to train stations and extend out of the centre of London to surrounding regions. Not all of the lines are in fact underground for the whole of their routes. Additions to the system have included the Docklands Light Railway, a privately owned railway that provides services to London Docklands.