Two cargo trains in China each carrying 4,000 tons of ballast parked on two separate sections of a railway bridge to prevent the overpass from being washed away in flash floods.

Video filmed in Mianyang City in southern Sichuan Province on July 11 shows the flooded river running under the Baocheng Railway Fujiang Bridge. A train loading 4,000 tons of ballast - the stones beneath the track - goes onto the bridge, in order to increase its weight.

According to reports, two trains stopped on the bridge for six hours until the floods gradually receded. Four train drivers were involved in the mission.

The drastic measures were sanctioned by China Railway Chengdu Group as the area suffered its worst floods in 50 years.