Re: How significant is the qinghai-tibet railway to China's military on the Tibet bor
The most strategically vital part of the track is deep inside of China running from the Plateau into the Western Interior and away from India. In time of hostilities I think it fair to say that it would be a priority target and therefore a priority asset for defence.
For Aircraft it would be a perilous deep strike mission whilst for missiles you only need read the thread about Chinese Air Superiority over Taiwan for views about the ability of missiles to strike a long and narrow target.
In general terms, any permanent high speed communications link is of strategic value. I know China is often criticised for its lack of Heavy Airlift, I would remind those critics that this is only an issue for Countries that try and project power over very long distances and across oceans. when you are a continental power with contiguous land connections to the areas you need to get to, road and rail are usually much faster and effective in moving very large quantities of men and equipment.
Quite agreed SampanViking. The Qinghai-Tibet Railway is, in strategic terms, thoroughly thought out, well protected for most of its length simply by the distances involved, and even then, it is still reasonably efficient in transporting large numbers of troops, equipment and supplies to Tibet (considering the fact that the line has to come west-north-west out of Lanzhou rather than directly west out of Chengdu - infeasible for military and engineering/fiscal reasons). The only really vulnerable part of the whole railroad is the Golmud-Lhasa line, and even then only to cruise missiles and bombers; most (not all) tactical fighter-bombers would have a tough time getting much farther than Lhasa.
Area/Theatre Air Defence of the line from Golmud to Lhasa would not be onerous, though it would not be a light burden either, particularly the Nagqu-Lhasa line, which would require quite a bit of Tactical Air Defence as well. The Lanzhou-Golmud line is almost invulnerable to anything but bombers and long-range cruise missiles. And they would have to pass over whatever Air Defences the PLA might see fit to deploy along the road from Chengdu to Lhasa, and then Air Defences along the Golmud-Lanzhou-Xi'an tracks. Finally, they would have to deal with PLAAF interceptors the whole way in. That would take some doing unless you had some
very advanced kit to work with and people who knew what they were doing with it.
I think crobato, adeptitus, and Totoro are the folks to comment much more specifically on the Air Defence aspects. I am very limited in those areas.
As to the movement of troops, equipment and supplies, etc., it is a strategic and operational, but not a tactical, solution to many problems the PLA might have in operating in the area. Not having to truck stuff over thousands of kilometres of roads
completely changes the ability of the PLA to move large Formations to the high plateau and especially to keep them sustained. Even large Formations up in the mountains are far easier to sustain by trucking or flying supplies in from the railhead at Lhasa to the troops along the Nepal/India/Bhutan frontiers.
The tactical aspect that is not changed however, is the need to acclimatize troops properly at those altitudes; they need at least a full year of acclimatization and training at such altitudes to be fully prepared for that sort of warfare. The PLA of course did this in the two years prior to the 1962 war with India, and when the Indian Army sent reinforcements from the Gangetic Plain, the troops suffered from altitude sickness. Recent unpleasantness over the past several months between Bhutan and China and India and China should be viewed with due gravity given the strategic and operational capability that the PLA will have at its disposal with the completion of the Qinghai-Tibet Railway.
If large PLA troop movements afforded by the impending completion of the railway subsequently take place, then it is clear that China is willing to fight for whatever strategic objectives it may have in the region (ie. access to fresh-water resources). China suddenly and publicly re-asserting its claim this spring to almost the whole of north-east India north of the Brahmaputra River coupled with the PLA destruction of Bhutan and Indian Army outposts in September and October suggest that something is afoot.
Econmically, the benefits of the Qinghai-Tibet Railway seem relatively modest by comparison to the strategic and military ones. Nevertheless, the railway is essential for sustainable economic development in the region, particularly for moving vast amounts of heavy construction equipment and supplies in order to engage in hydro-electric projects and the like.