Light rail services in Tuen Mun were severely disrupted on Friday morning after a grab truck allegedly damaged a section of overhead cable.

The accident happened at an intersection near On Ting station when the grab truck was turning a corner and its grab accidentally hit an overhead cable.

A video shows flashes of light and white smoke as the accident occurred.

MTR has diverted several light rail lines, including the 505, 507, 614 and 751 lines.

Services gradually returned to normal after the repair was completed around 1pm.

A 50-year-old truck driver has been arrested on suspicion of dangerous driving.

A passenger on a train affected by the accident said it suddenly lost power.

"The lights were suddenly turned off when the train was near the traffic light junction. The train was still moving at that time, but after a few seconds, it stopped. There was no electricity and air conditioning. Later, there was an announcement that there was a problem with the electricity supply," she said.

An elderly woman said she left home earlier than planned after hearing about the disruption.

"I'm going to pick up my grandchild from school, but the light rail trains aren't stopping at this station. I planned to go earlier. I went out one and a half hours early because I was worried that there may be traffic congestion," she said.