Risks of an epidemic in a two-layered railway-local area traveling network Zhongyuan Ruan, Pakming Hui, Haiqing Lin and Zonghua Liu Eur. Phys. J. B, 86 1 (2013) 13 Published online: 21 January 2013 DOI: 10.1140/epjb/e2012-30292-x