Trans-Iranian Railway

The Trans-Iranian Railway was a major railway building project started in 1927 and finished in 1939, under the direction of the Persian monarch, Reza Shah, to construct a basic network of railways joining the capital Tehran to the Persian Gulf and the Caspian Sea. The Trans-Iranian Railway was built entirely with local capital. Trans-Iranian Railway is 1394 kilometers (865 miles) long.

The first lines pass though formidable mountains, and international construction firms were heavily involved in the construction. Gradients up to 1 in 36 were required, plus hill climbing techniques such as spiral railroads were required.

Geological challenges

All sorts of geological problems were encountered, which required abandonment of some tunnels, and realignment of the route through different terrain:
* a tunnel through a salt dome had to be abandoned, since the disrupted water table would erode away the salt.
* a tunnel was started through apparently solid rock encountered powdery gypsum, which filled the excavation as fast as it was dug out - another abandoned tunnel.
* a tunnel through pumice was unblastable and un-digable since the picks and shovels got stuck.
* a tunnel encountered a large "void" or cavern in the mountain, requiring a bridge in the middle of the tunnel.
* poor fresh water supplies made mixing of long-lasting mortar and concrete problematic.
* large bridges like the Veresk Bridge were unavoidable crossing the Alborz mountains.

Despite these challenges, the principal lines were completed ahead of schedule and under budget, with the first train arriving in Tehran in about 1940.

World War II

During World War II, the railway was a vital component of the Persian Corridor supply routes connecting the Persian Gulf to Central Asia and the Soviet Union. The line was of such importance that the Allies imported rolling stock of their own design, including the new diesel locomotives such as the ALCO RSD-1.

TV

An exploration trip to find a cave-dwelling fish named after a man called Smith, was filmed (by the BBC?) travelling along this railway line, and some of the tunnels and deviations were visible.Fact|date=March 2008

ee also

*Abdolhossein Teymourtash
*Wagon Pars
*Persian Corridor
*Royal Road of ancient Persia
*Islamic Republic of Iran Railways