The line may be the most difficult rail project undertaken on the Indian subcontinent. The young Himalayas are geologically surprising and problematic. The track's alignment presents one of the greatest railway engineering challenges ever faced; only Tibet's Qingzang Railway, completed in 2006 across permafrost and climbing to over above sea level, is comparable. Although the Indian temperatures are less severe, the region experiences harsh winters with heavy snowfall. In the Pir Panjal Range, most peaks exceed in height.