Initially, an unsuccessful attack was launched by the 77th Parachute Brigade (Brig Atal) to capture Zoji La. Operation Duck, the earlier name for this assault, was renamed as Operation Bison by Lt Gen Cariappa, the Western Army commander. M5 Stuart light tanks of the 7th Cavalry regiment were moved in dismantled condition through Srinagar and winched across bridges while two field companies of the Madras Sappers converted the mule track from Baltal up the Zoji La to Gumri into a jeep track. The surprise attack on 1 November by the brigade with armour supported by two regiments of 25 pounders and a regiment of 3.7 inch guns, saw the Pakistanis being surprised. The pass was forced and the raider column pushed back to Matayan and later Dras. The brigade linked up on 24 November at Kargil with Indian troops advancing from Leh while the Pakistanis eventually withdrew northwards toward Skardu.