Tunnels excavation and consolidation are the most risky parts of the projects. The professional execution of tunnels will greatly reduce costs and improve the quality of the structure. Employing experienced experts plus utilizing up-to-date facilities has made this company one of the most capable in this field. Execution of Mashhad-Sarakhs 2400 m long tunnel NO.1 as one of the most prominent railway tunnels in the country indicates the capabilities of SDM.