Three men are being hunted by transport police after they threw a roll of tin foil at the overhead power lines at Central Station during rush hour yesterday.
The impact caused an electrical arc, similar to a flash of lightning, which struck platform 15 and left a large crater.
British Transport Police said it was lucky there was no-one on the platform at the time. The incident happened just after 6pm.
Eye witnesses described hearing a loud bang and seeing a flash of light.
The men, all believed to be 20-25, had thrown the foil from the adjacent NCP multi- storey car park which looks on to the platform. Engineers were called to fill in the hole.
The incident caused disruption to the 6.15pm Glasgow to Ardrossan service, however ScotRail said no other services had been affected.
Network Rail has previously warned of the dangers of flying kites or dangling objects from bridges near overhead power lines because of the risk of electrocution.
The electricity can arc like lightning or jump around nine feet.
A spokesman for British Transport Police said: "At 6.10pm we received a report that three men had been seen throwing a roll of tin foil from the NCP car park next to Central which hit the overhead lines.
"It caused the electricity to arc, which is similar to a lightning strike and caused a hole in the platform. The hole has now been filled in.
"It appears to have been a random act of vandalism and we appeal for witnesses to come forward."
Anyone with information is asked to contact British Transport Police on 0800 40 50 40.