Engineers found the dead rodent beside the damaged cable at Aberdeen railway station shortly after the power went out around 9.30am on Sunday.
Although trains services were not affected power was not restored until later in the afternoon, leaving the electronic departures board in the black.
Station staff put up posters displaying timetable information and were on hand to assist passengers.
A spokesman for Scottish Hydro Electric Power Distribution said: “From what we have been told, a rat got in among some of the equipment and did some damage to a cable.
“This in turn tripped our circuit breaker causing the power to go out.”
It is understood that power was off in the station for around six hours.
Engineers isolated the affected circuit but had to carry out further work before power could be restored.
British Transport Police later tweeted: “Power has finally been restored at #Aberdeen Train Station.
“We might get a wee cup of tea now!”
A spokeswoman for ScotRail confirmed the power was out at Aberdeen railway station for nearly 12 hours.
She added: “Train services were not affected by this issue, but customer information screens and lights within the station were out.
“We worked to source an alternative generator as quickly as possible and power was restored by around 10pm.
“We apologise to our customers affected by this power outage. Staff at Aberdeen station were on hand to help any passengers who required assistance.”