The Baikal-Amur Mainline (Russian Байкало-Амурская магистраль, Baikalo-Amurskaya magistral’, BAM) is a 1,520 mm broad gauge railway line in Russia. Traversing Eastern Siberia and the Russian Far East, the 4,324 km  long BAM runs about 610 to 770 km north of and parallel to the Trans-Siberian railway.

It was built as a strategic alternative route to the Trans-Siberian Railway, especially along the vulnerable sections close to the border with China. The BAM's costs were estimated at $14 billion, and it was built with special, durable tracks since much of it was built over permafrost.

The BAM departs from the Trans-Siberian railway at Tayshet, then crosses the Angara and the Lena rivers, proceeds past Severobaikalsk at the northern tip of Lake Baikal, past Tynda and Khani, crosses the Amur River at Komsomolsk-na-Amure and finally reaches the Pacific Ocean at Sovetskaya Gavan. There are 21 tunnels along the line, with a total length of 47 km. There are also more than 4,200 bridges, with a total length of over 400 km.

The first project Pacific Railway built through the northern tip of Lake Baikal in the Russian technology community was discussed in 1888, but after the expedition of Colonel N. Voloshinov, it was concluded that it is impossible construction of the railway in this region. Modern road construction started only in the 1970s and ended in the 2000s.

The railroad had the status of "Construction project of the century" in the last USSR, there were thousands of workers from all Russia and USSR. For example, this trains station Noviy Urgal (Новый Ургал) was constructed by workers from Ukraine:


Typical scenery from the train window – the northern mountains:

[img width=700 height=470]http://bam.railways.ru/rr/_bam_rr_so_6.jpg” />

[img width=700 height=479]http://bam.railways.ru/rr/_bam_rr_so_3.jpg” />

[img width=700 height=470]http://bam.railways.ru/rr/_bam_rr_so_11.jpg” />

The complex topography of the region created additional difficulties for the construction of the railway.  For example, the Chertov bridge: it is said, that train operators usually christen before entering this bridge since it very high and two-storey and is located in abrupt turn on a gradient. The composition was forced to maneuver between the hills, moving with a maximum speed of 20 km / h and had the risk to fall under the avalanche. On the climbs it was necessary to use the trains auxiliary locomotives.

[img width=700 height=466]http://bam.railways.ru/rr/_bam_b_devil_2.jpg” />

[img width=700 height=470]http://bam.railways.ru/rr/_bam_b_devil_1.jpg” />

For faster and more safety transportation through this mountain range was built Severomuysky Tunnel (Russian: Северомуйский тоннель). The tunnel is 15,343 metres (50,338 ft) long, the longest in Russia and the 5th longest tunnel in the world. 
The construction of the tunnel conducted in cooperation Russian, American and German experts.  Preliminary work on the tunnel started in 1975, with tunneling commencing on May 28, 1977. The tunnel was built through very difficult rock with four major faults and a great deal of underground water, some at 35 atmospheres (3.5 MPa) pressure. One method used was to pump liquid nitrogen into the rock, freezing the water until the cut could be sealed. In September 1979 workers broke into a fault connected to a 12,000 cubic meter underground lake. This required building a drainage tunnel and delayed work for eighteen months. An additional factor was the dangerous radiation inside the mountain, many workers have received radiation exposure.

The total length of the mining tunnel – 45 miles, along the entire length of the tunnel with smaller diameter is used for pumping water, placement of engineering systems and delivery of technical staff. Ventilation is provided by three vertical shafts. The security of the trains through the tunnel provides by the computer system of seismic, radiation control. To maintain the microclimate in the tunnel on both its portals have special gates that are opened for the passage of trains.

The entrance to Severomuysky Tunnel and the Chertov bridge:

[img width=700 height=466]http://www.bamts.ru/pro/madepro/images/severomuiskiy1.jpg” />

The tunnel inside:

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[img height=470]http://news.made.ru/pics/2010/06/24/260863.jpg” />

With the resources boom of recent years and improving economic conditions in Russia, use of the line is increasing. Plans exist for the development of mining areas, as well as one of Eurasia's largest coal deposits in the region. In connection with this, a number of branch lines have been built or are under construction.

It is also intended that the BAM should become an alternative route for container transport between Europe and the Pacific, although the single-track nature of most of the route and the lack of suitable connections at the eastern end currently stand in the way. Currently under discussion is the construction of a tunnel under the Strait of Tartary to Sakhalin Island, with the possibility of the further construction of a bridge or tunnel from Sakhalin to Japan. A tunnel from the mainland to Sakhalin was previously begun under Joseph Stalin, but was abandoned after his death. A second attempt in 2003 was also postponed during construction.

The BAM now also attracts the interest of Western railway enthusiasts, with some tourist activity on the line.