Slime moulds can produce networks as efficient, cost-effective and resilient as railway networks designed by people, despite having no central control over what they build. The finding was made by an international team analysing networks created by the slime mould Physarum polycephalum and then comparing them to the Tokyo rail network. They found that, in terms of the efficiency of transport, the cost of resources used, and the tolerance to damage, the self-organising mould could match human network designers. The team, from Hokkaido University and Hiroshima University in Japan and Oxford University in the UK, report their results in this weeks Science.