The 1,394-kilometre-long railway connects the Caspian Sea in northeastern Iran with the Persian Gulf in the country’s southwest.
Opened in 1938, the railway crosses two mountain ranges as well as rivers, forests and plains.
It was inscribed on the UNESCO World Heritage list in July.
According to the UNESCO, the railway is “notable for its scale and the engineering works it required to overcome steep routes and other difficulties”.
“Its construction involved extensive mountain cutting in some areas, while the rugged terrain in others dictated the construction of 174 large bridges, 186 small bridges and 224 tunnels, including 11 spiral tunnels,” the UNESCO said.
SQ/MM