May 1984: The railroad between Xining and Golmud was completed and opened to traffic.
December 2000: The official project proposal for the Qinghai-Tibet Railway was handed to the State Council.
February 8, 2001: The Qinghai-Tibet Railway project was approved and initiated.
June 29, 2001: Central government agrees to invest 26.21 billion yuan (US$3.27 billion) to build Qinghai-Tibet Railway. Construction of the line starts at Golmud, Qinghai Province. Ceremonies to mark the beginning of work are held simultaneously in Golmud and Lhasa, capital city of Tibet Autonomous Region.
May 2002: Tests begin on frozen soil.
March 2003: Track laying for Qinghai-Tibet Railway, which passes through the Kunlun Mountain Tunnel, is completed.
June 2003: Construction begins on the world’s highest railway station -- Tanggula Mountain Station
August 2003: Bridgework for Qinghai-Tibet Railway finished passing through the Hoh Xil Nature Reserve.
July 2004: 450 kilometers of track work completed.
August 24, 2005: Track laying work through Tanggula Mountain area completed
August 2005: Work finished on roadbed, tunnel, bridge and culvert.
October 12, 2005: Track laying for the whole line completed.
March 1, 2006: Trial operation of freight train on the line.
May 1, 2006: Trial operation of non-passenger train on the line.
July 1 2006: Trial operation of the whole line.
(China.org.cn)