Security of ATCS wireless railway communications

This paper covers the advanced train control systems (ATCS) protocol. ATCS is an open standard for radio frequency data systems in railroad networks. Currently ATCS is used for functions such as throwing track switches and changing track signals. Vulnerabilities in the ATCS protocol are discussed in this paper, along with a hobbyist program called "ATCS monitor" that decodes the signals. Finally the paper looks at the current mitigating factors for these vulnerabilities and proposes additional ones.