Small-world properties of the Indian Railway network
  Structural properties of the Indian Railway network is studied in the light of recent investigations of the scaling properties of different complex networks. Stations are considered as `nodes' and an arbitrary pair of stations is said to be connected by a `link' when at least one train stops at both stations. Rigorous analysis of the existing data shows that the Indian Railway network displays small-world properties. We define and estimate several other quantities associated with this network. 
Parongama Sen, Subinay Dasgupta, Arnab Chatterjee, P. A. Sreeram, G.   Mukherjee and S. S. Manna