Updated:A reservoir collapse in Shanxi, China has severly disrupted transportation and forced 20,000 people from their homes downstream. The top of an irrigation drain of the Quting reservoir caved in Friday morning, causing the partial collapse of the dam walls. Five railway lines were suspended and three delayed, affecting thousands of passengers returning home from Lunar New Year holidays. The floodwaters also swamped local farmland. State media said the dam collapsed because it was old.