回复：强渡大渡河, 红军飞夺泸定桥并非完全爬锁链

The main point was that the it miraculouly took only 2 days for the Red Army from both shores of Taidu River to reach Luting Bridge. That was a victory for the Red Army. If the Red Army could not do it, it would be annihilated by the Central Army. Whether there was a fight over the iron Luting Bridge.....?? The Bridge was protected by the local warload's (Liu Wen-hui) army who would not wholeheartedly fight for Chiang Kai-shek.
The Red Army accomplished the impossible with their own feets.