Definitely 72s. No 55s were ever stationed in Ladakh. OTOH 2 x squadrons of 72s were located in the region from 1988 to 1991. Besides a battalion of BMP-2s.
There was at least one T55 "somewhere in the Himalayas" at least till about 20 months ago. I can think of only two road-linked theaters that offer altitudes of 17,000+ feet in the Himalayas. A silent build-up will save many a rushed heli-drops.http://www.tribuneindia.com/2007/20070106/main9.htm
Army feat: Tank driven to 17,000 feet
Chandigarh, January 5
Somewhere in the snow-covered Himalayas during the bleak winters last year, the Army drove a T-55 tank up to the dizzying height of over 17,000 feet, setting a record of sorts. Never in the history of armoured warfare has a tank been taken up to this altitude before.
The operation was undertaken to evaluate the operational and logistical feasibility to transport and operate tanks at altitudes and to areas which have so far remained unexposed to armoured operations, should such a need arise. The task was carried out by 63 Cavalry Regiment.
“This is a stellar example of the grit and determination of the troops and their ability to move men and equipment against all odds and reach where required,” Lt Gen S.S. Mehta (retd) a former Colonel of 63 Cavalry Regiment, said. “Nowhere in the world has a tank been taken up to this altitude before,” he added.
Designed and developed for combat in plains and deserts, tanks have not been used for operations in mountains barring a few examples. The Indian Army Corps had redefined the parameters for armoured operations in the 1947-48 war, when Col (later Lt Gen) Rajinder Singh Sparrow of 7 Light Cavalry took tanks through the 12,000-foot-high Zoji La pass in Kashmir and threw back Pakistani forces. It was through this action that Dras was recaptured in 1947.
The 63 Cavalry had detailed a lieutenant colonel to head the operations. The entire exercise was an extremely complex task involving detailed planning and constant review of minor details. A lot of time was spent in selecting the route.
“The operation involved a lot of innovations and spur of the moment decisions, most of which were actually contrary to established technical norms,” an officer revealed. “At places there was three feet of snow and the temperatures were as low as minis 13 degree Celsius,” he added.
At that altitude, the oxygen content is just 4 per cent as compared to 17 per cent at lower altitudes, which greatly affects engine combustion,” the officer said. “We had to work out the fuel consumption and other technical aspects accordingly,” he added.
During the drive which took several days, special efforts were required to ensure that the batteries did not go dead because of the extreme cold. Precautions were also taken against the fuel and lubricants freezing at night. There were also instances where it was learnt that a task which required special tools could be accomplished by normal tools with a bit of imagination and expertise.
The tank started up from an altitude of about 14,000 feet and reached up to 17,000 through a narrow snow covered track, which at places was just enough to accommodate the tank’s width. The driver was later awarded Chief of the Army Staff’s Commendation.