Localization (position tracking) inside tunnels is difficult. GPS signal is not available inside tunnels, and installation of wireless access points is expensive. In this work, we propose the use machine vision for localization in tunnels. The advantage for such approach is that it requires no installation of any infrastructure, needed with radio triangulation approach. Prior researches have shown that machine vision can successfully identify positions in both outdoor and indoor environments. However, such application has never been tried inside tunnels. In this paper, we present our work on developing appropriate algorithms for localization in tunnels. One potential application for localization in tunnels is to help tunnel maintainers acquire accurate location information in tunnels when they do tunnel inspections and maintenances.