Network Rail said it took half an hour to rectify the problem at Waverley in Edinburgh, which the company said posed no risk to the public. But it caused a significant ripple effect on services on the east coast.
A spokesman said: "The delays were caused by a fault with the overhead power lines on platform seven.
"While this was not a danger to travellers, it was a fault which required the power through that part of the station to be switched off while engineers accessed the track and tightened up the support."
He added: "At that time of day in the station any fault is going to cause a lot of disruption and delay. Engineers responded as quickly as possible to rectify the fault and get trains on the move."