Two Chinese companies compete to build a permafrost crossing of the Lena River.
Dignitaries gather on Chinese side of the pipeline to witness the formal welding of the first joint in $55billion line.
Long-held dream for a crossing at Yakutsk gets a boost from China.
33 hour journey between the capitals could be in place by 2020.
150-strong delegation of Far East businesses attend the First Russia-China EXPO.
Construction launched on 3,968 kilometre 'Power of Siberia' gas pipeline.
Fears for plan to stimulate Russian economy via major infrastructure links to Asia and Europe as Beijing announces rival scheme.
Deputy premier Dmitry Rogozin stresses importance of boosting ties with Beijing.
New rail bridge linking the two countries symbolizes closest-ever economic co-operation between neighbors.