Up to 28,000 homes and businesses in Birmingham were hit by a power cut on Monday morning.
The loss of power affected the city centre, Winson Green, Handsworth and Edgbaston areas. There were 75 train delays at New Street Station.
Suppliers Central Networks said the power was off for more than two hours until engineers restored it.
A spokeswoman said investigations were now ongoing to find out what had caused the problem.
She said the power went off at 0815 GMT and was back on at 1030 GMT.
The Mailbox complex, including BBC Birmingham and Network Rail, was one of the commercial premises affected by the loss of power.
Two Midlands Today programmes, at 0828 GMT and just before 0900 GMT, were not broadcast.
Network Rail said it suffered an IT systems failure at both its Mailbox headquarters and at New Street Station.
The power cut also affected signals and led to delays for individual train services.
A spokeswoman said Virgin Trains, Central Trains and Arriva Trains Wales' services had been hit on the Wolverhampton to Birmingham line.
Six schools were also closed as a result of the power cuts.