Anzob Tunnel Road. It is also a transit route between Dushanbe and Uzbekistan's capital Tashkent. Prior to construction of the tunnel, especially during winter, the threat of year-round avalanches led to periodic disruptions of commerce. The tunnel was officially opened in March 2006; it was built by the Iranian Sabir Co. Due to the significance of the tunnel, limited traffic flow was permitted via signing a waiver form noting potential hazards such as flooding and smog from construction equipment operating inside the tunnel prior to the final construction phase which may have included installation of ventilation and drainage infrastructure. As of May
Severn Tunnel Severn between Sharpness and Lydney opened to traffic during 1879. On 22 October 1884 laying the double tracks in the tunnel started. On 18 April 1885, the final brick was placed in the tunnel's lining. The tunnel was horse shoe-shaped in cross-section with a concave floor, its height was 6.1 meters above the rails with a maximum width of 7.9 meters. An enclosed 533mm high drainage channel, in the form of an upturned semi-circular tunnel, is built onto the tunnel invert, 1.4 meters below the rails. Around 76.4 million bricks were used in the tunnel's construction. The brickwork is between