 Complete the following phrase:  The long Trans-Iranian Railway from Bandar Torkaman on the Caspian Sea to Bandar Shahpur on the Persian Gulf was opened during the reign of Reza Shah Pahlavi in 1939. The railroad was built with rail weighing 67 pounds per yard 33 kgm and required more than 3000 bridges. There were 126 tunnels in the Zagros mountains. The longest was 1.5 miles. Grades averaged 1.5 percent south of Tehran, but then increased to 2.8 percent to cross the 7,270-foot pass between Tehran and the Caspian Sea. After the 