A blackout knocked out power to 136,700 customers in parts of Manhattan and the Bronx Wednesday, bringing subway service to a grinding halt in the process.

A Con Ed spokesman said the outage started at 3:42 p.m. and all power was restored by 4:30 p.m. The utility company is investigating the possibility of a "transmission disturbance" due to the 90-degree temperatures. Frustrated Hunts Point straphangers were ushered off trains and out of stations in the sweltering sun to take buses. The MTA said service was returning with delays on the 4, 5, 6, D, E and V lines after Con Ed worked on the problem. Service also came to a standstill on other lines during the outage.The blackout caused problems in the Bronx neighborhoods of The Hub, Mott Haven, around Yankee Stadium, at Lincoln Hospital and municipal Bronx buildings.

In Manhattan, the blackout forced the evacuation of the Metropolitan Museum of Art. Mayor Michael Bloomberg lost power at his private home and at the official mayoral residence. Residents were also forced to deal with the heat without air conditioning.

AP wire reports contributed to this story.