Several kilometres of an aluminium conductor rail on the elevated Pink Line monorail system fell onto a street in Nonthaburi early Sunday morning. Three vehicles were damaged, but no casualties were reported.

The incident happened at about 5am along Tiwanon Road in Pak Kret district of Nonthaburi. A 5km stretch of the metal rail – about 10 centimetres wide and 5cm thick – fell from the elevated structure of the Pink Line from Chon Prathan market to Khae Rai intersection. Conductor rails supply power to electric trains.

Eyewitnesses were vendors who parked their vehicles on the road. They said they saw bolts fall first, and then the rail collapsed and hit their vehicles. The falling rail also snagged on a power pole, leaving it at an angle.

Transport Minister Suriya Jungrungreangkit later blamed the rail collapse on soil at the system's construction site.
                 
Inspecting the scene on Sunday, Mr Suriya said officials believed that soil dropped from a lifted sheet pile might have fallen onto the tracks along the Pink Line. A patrol train that normally runs from 4am every day then is thought to have run over the soil, causing the train to shake and pull the conductor rail loose.

The minister said that a crane was used to lift sheet piles from the construction site of the Pink Line system to reopen traffic lanes earlier closed for the monorail construction.

It would take about seven days to pick up the fallen conductor rail and reinstall it. The work would be done at night.

The Pink Line could resume service at 23 stations between Chaeng Wattana and Min Buri stations on Monday except for the affected section between Nonthaburi Civic Center and Pak Kret Bypass stations where there were seven stations altogether.