Operators of Singapore's Mass Rapid Transit (SMRT) system have refuted claims that a passing tram could have caused Mark Webber's retirement from the recent night grand prix there.

Red Bull Racing officials said after the race that the Australian driver's broken gearbox could have been caused by the static electricity carried by a tram line beneath the track at turn 13.

But according to the news wire service AFP, SMRT refuted the claim.

"There is no MRT track beneath turn 13. The nearest MRT tunnel is about 200 metres away, with a depth of about 10 metres," a spokesman said."

He added that the train wheels and running wheels "do not generate static electricity".

Source: GMM